JP3418580B2 - Method and apparatus for producing esterified product - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an esterified product and an apparatus therefor. For more information,
By the esterification reaction of an alcohol represented by the formula: R ¹ O (R ² O) _n H with (meth) acrylic acid, high-quality (meth) acrylic acid esters (herein The present invention relates to a method and an apparatus for efficiently producing

[0002]

2. Description of the Related Art Cement dispersants, calcium carbonate, carbon black, pigment dispersants such as inks, scale inhibitors, dispersants for gypsum / water slurries, dispersants for CWM, thickeners, etc. The various alkoxypolyalkylene glycol mono (meth) acrylic acid ester-based monomer components used as raw materials are obtained by esterifying an alkoxypolyalkylene glycol and (meth) acrylic acid. In such an esterification reaction, reaction product water is by-produced at the same time. Therefore, if this reaction product water is not removed from the reaction tank (that is, if the reaction product water accumulates), the reaction tends to form an esterified product due to the equilibrium reaction. I will not progress. Therefore, for example, Japanese Patent Laid-Open No. 9-328346.
As can be seen in Comparative Example 1 of Japanese Patent Laid-Open Publication No. 1993-331, water is used for synthesizing various alkoxypolyalkylene glycol mono (meth) acrylic acid ester-based monomer components which are raw materials of polymer components used for cement dispersants. A method has been adopted in which a separator is provided so that the reaction product water can be separated. More specifically, as a synthesis of an alkoxypolyalkylene glycol mono (meth) acrylic acid ester-based monomer by an esterification reaction, a reaction vessel (separable flask) is provided with a thermometer, a stirrer, and a water separator, and reaction product water is supplied. Methacrylic acid, methoxypolyethylene glycol (average number of moles of oxyethylene group added: 10 moles), sulfuric acid as an acid catalyst, phenothiazine as a polymerization inhibitor, and cyclohexane as a solvent were charged into a reactor which was made separable and heated with stirring. The cyclohexane-water azeotrope is distilled off under normal pressure, and the cyclohexane is refluxed while removing the reaction product water with a water separator.

However, as disclosed in the above-mentioned publication, except for providing a water separator for separating and removing the reaction product water during the esterification reaction, the reaction product water is separated and removed. The current situation is that there has been no report on the technical issues in the past.

[0004]

Therefore, when the present inventors are diligently distilling and condensing the azeotrope of the solvent-reaction product water in the process of earnestly researching in order to efficiently produce a high-quality esterified product, , A gel is formed, and a part of it is refluxed together with the solvent, so that it remains as an impurity in the reactor and is mixed in the final product, and the product (for example, cement dispersant, pigment dispersant , Scale inhibitors, gypsum / water slurry dispersants, CWM dispersants, thickeners, etc.) and the quality of the ester, and when industrially mass producing an esterified product, the gel The particulate matter adheres to the inner wall of a pipe or a device (for example, a condenser) used for the condensation-separation / removal means of the reaction product water, resulting in a decrease in heat exchange efficiency at the time of condensation. ,repetition( In the case of continuous operation, the flow of the fluid (mainly the liquid after condensation) in the condenser and pipes may be deteriorated, which may lead to blockage. It was found that many technical problems caused by the gel-like substance occur, such as the need to clean the inside of the pipe and the pipe to remove the gel-like substance, and a solution to such technical problem is disclosed in Japanese Patent Application No. 10-268.
Proposed to No. 121. According to the invention proposed in Japanese Patent Application No. 10-268121, most of gel-like substances produced when the reaction product water is separated and removed are poly (meth) acrylic acid, and such gel-like substances are low boiling point raw materials. A part ((meth) acrylic acid, etc.) is formed (by a liquid phase reaction) when it is distilled and condensed together with the azeotrope of the solvent-reaction product water, and the generation mechanism (cause of generation) ), And based on this, a solution that can very effectively prevent the generation of the gel-like material was made. That is, in the method proposed in Japanese Patent Application No. 10-268121, in a method for producing an esterified product by an esterification reaction of an alcohol represented by the formula: R ¹ O (R ² O) _n H and (meth) acrylic acid, The reaction product water generated during the esterification reaction is distilled off, and the distillate containing the reaction product water is caused to act with a polymerization inhibitor, preferably the polymerization inhibitor solution is dropped to the top of the condenser. . As a result, it is possible to efficiently produce a high-quality esterified product by condensing the distillate containing the reaction product water and liquefying it to prevent the gelled substance itself from occurring during the separation and removal of the reaction product water. is there.

However, the inventors of the present invention have filed Japanese Patent Application No.
As a result of further diligent study in the method proposed in No. 268121, if the amount of the polymerization inhibitor solution to be dropped on the top of the condenser is small, the wall surface will not be sufficiently wet and the effect will be small. However, when the amount of the polymerization inhibitor solution is increased, the amount of the dehydrated solvent finally refluxed in the reaction tank is increased, and the following (1)
It was found that the problems of (2) and (2) occur.

(1) When the amount of the dehydrating solvent returning to the reaction tank is kept constant, it is necessary to newly provide a storage unit (tank or the like) for temporarily storing the dehydrating solvent on the circulation path, and the dehydration accumulated in the storing unit. The amount of solvent gradually increases, necessitating a very large storage area. In addition, the amount of dehydrated solvent used increases and the cost increases. Alternatively, it is necessary to install a series of devices for appropriately extracting (reusing or discarding) the excess dehydrated solvent from the circulation route, which leads to an increase in costs such as new capital investment and securing a site for installation.

(2) When returning the entire amount of dehydration solvent to the reaction tank, the dehydration solvent in the reaction tank gradually increases, the reaction temperature decreases,
It takes time to complete the reaction. Alternatively, as the dehydration solvent in the reaction tank increases, the amount of heat supplied to the reaction tank can be increased to maintain the reaction temperature, but the amount of heat for heating up to the excess dehydration solvent is wasted, and Temperature control is difficult and costly. Also, a large reaction tank is required.

Therefore, an object of the present invention is to provide the formula: R ¹ O
In the method for producing an esterified product by the esterification reaction of an alcohol represented by (R ² O) _n H and (meth) acrylic acid, a distillate is treated with a sufficient amount of a solution containing a polymerization inhibitor. The present invention provides a method for producing an esterified product and an apparatus therefor, which can always effectively prevent the generation of a gel-like substance on the distilling route and can efficiently produce a high-quality esterified product at low cost. ..

Another object of the present invention is to provide a distillate with a sufficient amount of a solution containing a polymerization inhibitor when a dehydrating solvent is used in the above method for producing an esterified product. In addition to the above, the present invention provides a method for producing an esterified product and an apparatus therefor capable of efficiently producing a high-quality esterified product at a low cost while suppressing an increase in the amount of the condensation residual liquid returned to the reaction tank. .

[0010]

Means for Solving the Problems As a result of intensive studies to solve the above technical problems, the present inventors have found that at least a condensation solution is obtained as a gelation inhibitor solution that acts on distillate distilled from a reaction tank. A mixture containing a part of the liquid, especially a part of the condensate (particularly a part of the condensate residual liquid after separation and removal of the reaction product water returned to the reaction tank) is added to the polymerization inhibitor solution and mixed. The inventors have found that the above technical problems can be solved by using the materials, and have completed the present invention.

That is, the object of the present invention is to provide the following (1)
It is intended to be achieved by an ester KaSo location shown to (8).

(1) The following formula:

[0013]

[Chemical 6]

(However, R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms, R ² O represents an oxyalkylene group having 2 to 18 carbon atoms, and the repeating unit of each R ² O is They may be the same or different, and when R ² O is in the form of a mixture of two or more kinds, the repeating units of each R ² O may be added in blocks or randomly. And n represents the average number of moles of addition of the oxyalkylene group, 0 to 3
00) and a reaction tank for carrying out an esterification reaction of an alcohol with (meth) acrylic acid, a condenser for condensing and diluting a distillate distilled from the reaction tank, and an antigelling agent. feed mechanism, and including a water separator for separating off water from the condensate resulting from the capacitor
A an ester apparatus, the anti-gelling agent supply mechanism connecting pipe and / or on the between the reaction tank and the condenser
Provided in at least one place in the condenser, reduced the
Also distills the gelation inhibitor solution containing a part of the condensate
An esterification device characterized by acting on an object . (2) The gelation inhibitor supply mechanism is a gelation inhibitor solution.
Nozzle part to act on is installed near the top of the condenser tower.
The anti-gelling agent supply mechanism according to the above (1).
apparatus. (3) The nozzle part is provided with the gelling agent solution facing upward.
The device according to (2) above, which is installed so that it can be supplied. (4) The anti-gelling agent supply mechanism stores the anti-gelling agent.
First supply after supplying anti-gelling agent from the warehouse to the nozzle
Second supply for supplying a part of the condensate to the passage and the nozzle part
Described in any one of (1) to (3) above, which has a route.
On-board equipment. (5) In the above formula (1), n is oxyalkylene.
It represents the average number of moles of addition of the group, and is a number of 2 to 300,
The apparatus according to any one of (1) to (4) above. (6) The anti-gelling agent solution contains a part of the condensate and the solution.
And / or an anti-gelling agent in solid form,
The device according to (1). (7) The anti-gelling agent is mixed with a solvent of the same kind as the dehydrating solvent.
The device according to (1) above, which operates in a combined form. (8) The following formula:

[Chemical 4] (However, R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms.
R ² O is oxyalkylene having 2 to 18 carbon atoms
And a repeating unit of each R ² O is the same.
May be present or different, and R ² O is
When it is in the form of a mixture of two or more kinds, each R ² O
Even if the return unit is added in blocks,
May be added in the form of a chain, and n is an oxyalkyl.
It represents the average number of moles of addition of len group, and is a number from 1 to 300.
Alkoxy polyalkylene glycol represented by
By esterification reaction with (meth) acrylic acid
Alkoxy polyalkylene glycol mono (meth) a
Acrylic acid-based monomer (a) is obtained, and the alkoxypolyalkyl
Lenglycol mono (meth) acrylic acid type monomer (a)
5 to 98% by mass, the following formula (2):

[Chemical 5] (However, R ³ represents hydrogen or a methyl group, and M ¹ is
Hydrogen, monovalent metal, divalent metal, ammonium group or organic
A (meth) acrylic acid-based unity
95% to 2% by weight of the monomer (b), and a monomer (b)
Other polymerizable (c) 0 to 50 mass% (however,
(The sum of (a), (b) and (c) is 100% by mass)
Copolymerized polycarboxylic acid-based copolymer dispersant
The above-mentioned alkoxy polyalkylene glycol mono
The production of the (meth) acrylic acid-based monomer (a)
The device described in (1) above.

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

DETAILED DESCRIPTION OF THE INVENTION According to the first concept, the present invention comprises:
The following formula:

[0039]

[Chemical 11]

(Wherein R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms, R ² O represents an oxyalkylene group having 2 to 18 carbon atoms, and the repeating unit of each R ² O is They may be the same or different, and when R ² O is in the form of a mixture of two or more kinds, the repeating units of each R ² O may be added in blocks or randomly. And n represents the average number of moles of addition of the oxyalkylene group, 0 to 3
In the method for producing an esterified product by the esterification reaction of an alcohol represented by the number 00 (herein, also simply referred to as “alcohol”) and (meth) acrylic acid, at least a part of the condensate is The present invention provides a method for producing an esterified product, characterized in that the gelation inhibitor solution contained therein is allowed to act on a distillate.

As a result, a sufficient amount of the solution containing the anti-gelling agent can act on the distillate, and the gel-like substance can be always effectively prevented from being generated on the distillate route. Therefore, high quality esluride can be efficiently produced at low cost.

As a method for producing the esterified product of the present invention,
Preferably, in the method of producing an esterified product by the esterification reaction of the alcohol of formula (1) and (meth) acrylic acid in the presence of a dehydrating solvent, the reaction product water produced during the esterification reaction is distilled off together with the dehydrating solvent. And distillate the reaction product water-containing distillate, to separate and remove the reaction product water from the condensed and liquefied condensate, and to obtain a condensation residual liquid containing a dehydrated solvent after the reaction product water is separated and removed. When the esterification reaction is carried out while returning to the reaction tank, the anti-gelling agent solution containing a part of the condensation residual liquid and the anti-gelling agent acts on the distillate.

As a result, the amount of the condensation residual liquid which increases in the reaction tank is suppressed as much as possible, and the distillate is condensed (particularly, the wall surface of the condenser where the distillate is condensed and liquefied, particularly the tower). A sufficient quantity of anti-gelling agent solution can be constantly fed (downward from the top of the condenser) so that the top wall can be sufficiently wetted. Therefore, while the reaction product water in the reaction tank is distilled from the reaction tank and then condensed and liquefied to be separated and removed, the formation of a gelled substance due to the low boiling point raw material distilled together with the reaction product water is always effective. Therefore, high quality esluride can be efficiently produced at low cost.

In the present specification, the "distillate" means a substance (mixture) obtained by distilling from the reaction tank, and will be described in detail below. During the esterification reaction step or the esterification reaction step Regardless of the type of process such as the dehydration solvent distillation process after completion, all those distilled from the reaction tank are included. Therefore, the distillate according to the present invention is not particularly limited in the state in which it is present, and may be present in either a gaseous state or a liquid state. That is, unless otherwise specified, the “distillate” in the present specification is the reaction product water produced during the esterification reaction step and distilled off from the reaction tank, and the reaction product water together with the reaction product water when distilled from the reaction tank. A distillate containing a raw material distilled in particular, particularly (meth) acrylic acid, and optionally a dehydrating solvent added to the reaction vessel for the purpose of azeotropically simmering with the reaction product water; and dehydration after the completion of the esterification reaction step Dehydration solvent distilled off from the reaction tank during the solvent distillation step, and raw materials that are distilled off together when the dehydration solvent is distilled off from the reaction tank, especially distillate containing (meth) acrylic acid. Include. Incidentally, the reaction tank here is not limited to its name, but is used with the same meaning as a reactor, a reaction vessel, a reaction kettle, etc., and should be understood most widely. Hereinafter, for convenience of description, the expressions in these may be appropriately used, but the present invention should not be limited to the narrow meanings of each individual. Similarly, neither the condenser (condenser) described later nor the water separator is to be understood by its name, rather than by its name.

In the first concept, the mode in which the gelation inhibitor solution is caused to act on the distillate distilled by the esterification reaction, that is, the reaction product water produced during the esterification reaction is distilled with the dehydrating solvent. It includes a mode in which the anti-gelling agent solution is allowed to act on the distillate.

The anti-gelling agent solution used in the production method of the present invention is a solution which acts on a distillate, and more specifically, it prevents gelation (formation of gel) with respect to a low boiling point raw material in the distillate. A solution which acts for the purpose of doing so contains at least a part of the condensate, preferably a part of the condensate and an antigelling agent. At this time, the gelling agent may be used as it is or in the form of a solution, but in consideration of easiness of handling, the solution form is preferable, and the gelling agent used in the present invention is preferable. It is more preferred that the solution contains a part of the condensate residual liquid and an anti-gelling agent in the form of a solution.

In the present specification, the term "condensate" means that which comes out from the outlet of the condenser.
Further, according to the present invention, the gelation inhibitor solution may be allowed to act on the distillate such as the reaction product water produced during the esterification reaction. Included in condensate. Further, after that, since it is separated into a condensate residual liquid and a separated water by a water separator, both the condensate residual liquid and the separated water are included in the definition of the condensate liquid, and these can be used independently of each other. Further, “a part of the condensate” includes not only a part of the condensate that is simply separated but also a condensate residual liquid obtained by separating the condensate and a part of the condensate residual liquid. Furthermore, the "condensation residual liquid" refers to the solvent-side component separated by the water separator, and the "separated water" refers to the water-side component separated by the water separator that is the water separating means. The components on the solvent side include, in addition to the gelation inhibitor solution, a dehydrating solvent and the like used as necessary. The water-side components include reaction product water and raw materials. The above condenser and water separator are used as follows in the method for producing an esterified product of the present invention. That is, in the method for producing an esterified product of the present invention, it is necessary to distill off the reaction product water generated during the esterification reaction from the reaction tank, but the distillate also contains components other than the reaction product water as described above. Since it is included, it is not possible to release it directly into the atmosphere due to problems such as environmental pollution.Therefore, it is necessary to make it possible to appropriately treat and reuse this reaction product water after distilling it from the reaction tank. . Therefore, what is distilled from the reaction tank is sent to a condenser (condenser) and used to condense and liquefy. Furthermore, what came out of the outlet of the condenser is sent to a water separator, and it is separated into two layers by utilizing the difference in the property, and the separated water consisting of the components on the water side of one layer and the water of the other layer are separated. It is used to separate the residual liquid from the solvent-side components.

In addition to the above-mentioned part of the condensate, the gelling agent solution contains a gelling agent (including the form of a solution; the same applies hereinafter) and other additives such as, for example,
An acid catalyst or the like, which is appropriately added for the purpose of supplementing the reaction tank, may be contained.

As described above, the gelling inhibitor is dissolved (or mixed, for example, in the supersaturated state, a part of the gelling inhibitor is not dissolved but dissolved in a suitable solvent, preferably the same solvent as the dehydrating solvent. If two or more anti-gelling agents are used and some of the anti-gelling agents are contained in the solvent without being dissolved, further the anti-gelling agent is mixed. It is preferable that it is also included).

The gelling agent used in the present invention is particularly preferably one which can suppress the polymerization reaction which takes place at the stage where the low boiling point raw material distilled along with the reaction product water is condensed. The anti-gelling agent is not limited and can be appropriately selected and used from various conventionally known gelation inhibitors. Examples of the antigelling agent include phenothiazine, tri-p-nitrophenylmethyl, di-p
-Fluorophenylamine, diphenylpicrylhydrazyl, N- (3-N-oxyanilino-1,3-dimethylbutylidene) aniline oxide, benzoquinone, hydroquinone, methoquinone, butylcatechol, nitrosobenzene, picric acid, dithiobenzoyl disulfide, Examples include cuperon and copper (II) chloride. Of these, phenothiazine, hydroquinone, and metoquinone are preferably used because of their solubility in a solvent such as a dehydrating solvent and the reaction product water. These anti-gelling agents may be used alone or in combination of two or more.

The amount of the above gelling agent used is such that gel formation is always effectively prevented for low boiling point raw materials that are successively distilled from the start of distillate distillation to the end of the esterification reaction. It is necessary to be an amount (cumulative amount from the start of distillation of the distillate to the end of the esterification reaction). Further, when a dehydrating solvent is used in the esterification reaction and the dehydrating solvent is distilled out and refluxed, the gelation inhibitor separates the water produced by the reaction after achieving the purpose of preventing polymerization of the distillate. After being removed, it is returned to the reaction tank in a state of being dissolved in the condensation residual liquid side,
It is gradually accumulated in the reaction tank. As a result, the esterification product obtained by the reaction is used as a raw material for polymerization, which makes it difficult to polymerize when producing various products such as cement dispersants. Therefore, it is desirable to suppress the amount of the gelling agent used as much as possible. From the above viewpoints, the amount of the gelling agent used is 0.1 to 1000 mass ppm, preferably 1 with respect to the total amount of the raw materials alcohol and (meth) acrylic acid used.
˜500 mass ppm. When the amount of the antigelling agent used is less than 0.1 mass ppm with respect to the total amount of the raw materials used, successive distillation is performed from the start of the distillation of the distillate containing the reaction product water to the end of the esterification reaction. Since the amount of the low boiling point raw material is insufficient for always effectively exhibiting the polymerization inhibiting ability, a gelled product may be formed. On the other hand, when it exceeds 1000 mass ppm with respect to the total amount of the raw material used, the amount is too large to effectively exhibit the polymerization inhibiting ability, and further effects commensurate with excessive addition cannot be expected, which is uneconomical. In addition to the above, the polymerization becomes difficult when various products such as cement dispersant are produced by polymerizing the obtained esterified product as a raw material. The total amount of the anti-gelling agent used was added at a time, so that the low boiling point raw materials that are successively distilled from the start of the distillation of the reaction product water to the end of the esterification reaction Since it is difficult to effectively prevent the formation of a gelled substance, it is desirable to continuously add the gelling inhibitor within the above-specified range. At this time, it is more preferable to adjust the concentration of the gelling agent in the gelling agent solution so that it will always fall within the range specified below with respect to the low boiling point raw materials that are successively distilled out, and to add them continuously.

The solvent that can be used when the gelling inhibitor is used in the form of a solution is not particularly limited, and examples thereof include benzene, toluene, xylene, cyclohexane, acetone, methyl ethyl ketone, n-hexane, Examples include heptane. Further, when using a dehydration solvent in the esterification reaction and distilling and refluxing the dehydration solvent, the solvent component used in the gelation inhibitor solution is also contained in the condensation residual liquid side and returned to the reaction tank, It is desirable that it can effectively act as a dehydrating solvent in the esterification reaction tank. In particular, when a solvent different from the dehydration solvent charged in the reaction tank is used, the azeotropic point of the dehydration solvent containing the solvent and the water produced by the reaction is gradually increased by gradually increasing the amount (concentration) of the solvent in the reaction tank. And the distilling rate accompanying this change over time, so control and control of the amount of heat added to the inside of the reaction tank,
Furthermore, as the number of raw materials increases, the number of facilities increases, and safety, quality control, inventory control, etc. become complicated or complicated, so that the same type of solvent as the dehydrated solvent loaded in the reaction tank is better. preferable.

The main purpose of use of the solvent here is to make the gelling agent into a solution, so that it can be easily mixed with a part of the condensate, and stirring is performed when mixing with a part of the condensate. This is to eliminate the need for providing a device or the like (for example, a stirring tank or the like). Then, when a dehydrating solvent is used in the esterification reaction and the dehydrating solvent is distilled out and refluxed, in order to suppress the increase in the amount of the condensation residual liquid returned to the reaction tank as much as possible, the condensation used in the gelation inhibitor solution is used. Since it is better that the mixing ratio of a part of the liquid (preferably the residual liquid after condensation) is higher, it is desirable to suppress the amount of the solvent used here as much as possible. From this point of view, the concentration of the gelling agent in the solution is 10 mass ppm to the saturated concentration, preferably 100 mass ppm to the saturated concentration, and more preferably 200 mass ppm to the entire solution.
Saturation concentration, particularly preferably a concentration corresponding to 200 mass ppm to 95% of the saturation concentration (however, the saturation concentration varies depending on the type of gelling agent and solvent, temperature, pressure, etc. and is not uniquely determined. , Specific numbers are not specified). By using a saturated solution, the amount of solvent used can be minimized. Furthermore, in order to keep the concentration of the gelling agent that falls from the capacitor constant, it is better to have a slightly lower concentration than the saturation concentration that changes with temperature. It is preferably used. When the concentration of the antigelling agent is less than 10 mass ppm with respect to the entire solution, the mixing ratio of a part of the condensate used in the antigelling solution decreases, and a dehydrating solvent is used for the esterification reaction. When the dehydrated solvent is used and is distilled out and refluxed, the amount of the condensed residual liquid returned to the reaction tank increases. Alternatively, a large storage unit that can store the gradually increasing condensate residual liquid until the end of the esterification reaction, or a device for discharging a part of the condensate residual liquid out of the system over time.
Means, etc. are required. Furthermore, the amount of solvent used increases and the cost increases.

Regarding the flow rate (flow rate) of a part of the gelling inhibitor and the condensate used in the gelling agent solution, the concentration of the gelling agent in the gelling agent solution and the reaction device (reaction tank It cannot be specified unconditionally because it depends on the size of pipes, pipes, condensers, etc.) and the amount of distillate, etc., but the amount of anti-gelling agent should be reduced and a sufficient amount of condensate should be used instead. When used, a sufficient amount of the gelation inhibitor solution can be caused to act on the distillate, and when a dehydrating solvent is used for the esterification reaction and the dehydrating solvent is distilled out and refluxed, the reaction mixture is used in the reaction vessel. The amount of the solvent may be appropriately determined (specified) according to the usage mode so that the increase in the amount of the solvent can be suppressed as much as possible. The flow rate per minute of the gelling inhibitor per 1 m of the diameter (inner diameter) of the condenser is 0.01 to 40.
L / min m, preferably 0.1 to 15 l / min m, more preferably 0.1 to 5 l / min m,
The flow rate of a part of the condensate per minute with respect to the diameter (inner diameter) of the condenser is 1 to 1000 liters / min.
Minute m, preferably 5 to 500 liters / minute m, more preferably 10 to 200 liters / minute m. If the flow rate of the antigelling agent is less than 0.01 liter / minute m, the concentration of the antigelling agent in the solution will decrease, and it will be difficult to always exhibit a sufficient polymerization inhibiting ability. On the other hand, when the flow rate of the antigelling agent exceeds 30 liters / minute m, the amount of the solvent newly added increases, so the amount of the antigelling agent is reduced, and instead of this, a sufficient amount of condensation is condensed. It becomes difficult to achieve the purpose of the present invention using a liquid. Further, when the flow rate of a part of the condensate is less than 1 liter / minute m, it is not possible to always supply a sufficient amount of the condensate to the distillate, which may lead to the generation of gel-like substances. It is not preferable because it is present. On the other hand, when the flow rate of a part of the condensate exceeds 1000 liters / minute m, no further effect commensurate with supplying at a higher flow rate than this can be obtained, and such a large amount of condensate is supplied at a high flow rate. It is uneconomical to install a device (a large pump, a large diameter or a pressure resistant pipe, etc.) for doing so.

As described above, the flow rate of the gelling inhibitor is determined (specified) according to the use mode, and the flow rate of a part of the condensate, preferably a part of the residual liquid, is determined (specified). Any combination of flow rates is possible as long as it is within the specified flow rate range. The mixing ratio with the parts is preferably the following combination.

A part of the condensate is 0.5 to 10000 parts by mass, preferably 1 to 100 parts by mass with respect to 1 part by mass of the gelling inhibitor.
The amount is 0 parts by mass, more preferably 10 to 1000 parts by mass, and particularly preferably 10 to 100 parts by mass. When the amount of the condensate is less than 0.5 parts by mass with respect to 1 part by mass of the gelling agent, the above-mentioned gist of the present invention cannot be sufficiently satisfied, which is not preferable. On the other hand, when a part of the condensate exceeds 10000 parts by mass with respect to 1 part by mass of the gelation inhibitor, it becomes difficult to stably mix the both. These mixing ratios may be constant or variable, and the mixing ratio may be appropriately determined so as to satisfy the above-mentioned gist of the present invention.

In the present invention, the method of causing the gelling agent solution to act is not particularly limited as long as it can effectively act on the distillate, particularly the distilled low boiling point raw material. However, it can be carried out by appropriately using conventionally known methods (means). Preferably, a region for condensing and liquefying a gaseous distillate, specifically, a region for condensing and liquefying a gaseous distillate, such as a heat exchanger, a cooler, or a condenser (in this specification, these (Also collectively referred to simply as a condenser), especially at the gas inlet portion at the top of the condenser where the gaseous distillate begins to condense and liquefy,
It is desirable to allow the anti-gelling agent solution to act effectively. For that purpose, the area where the gelling agent solution is present is not limited to the inside of the condenser, and the gelling agent solution acts near the top of the condenser, that is, in the distillation path immediately before the condenser or in the distillation path immediately before the condenser. It is desirable to keep the inner wall of the capacitor always wet by doing so. As a specific example,
From the nozzle installed upward in the center of the top of the condenser to the inner wall of the gas inlet at the top of the condenser (because the first condensate liquefaction occurs, and at the same time gelation of the low boiling point raw material also occurs) A method of keeping the inner wall of the condenser always wet by spraying, blowing, spraying, ejecting, blowing up, or lowering the gelling agent solution, or a distilling route immediately before the condenser (for example, , The pipe 123 in FIG. 1 described later
And a path formed by the pipe 503 in FIG. 2; in the present specification, a nozzle part is installed in the “overhead line” (see FIG. 3), and the gelling agent solution is sprayed (or blown out) here. ) A method of keeping the inner wall of the capacitor in a wet state by allowing it to reach the inside of the capacitor through the wall of the overhead line is not limited to these. Furthermore, when a dehydrating solvent is used in the esterification reaction and the dehydrating solvent is distilled out and refluxed, when the distillate is condensed and liquefied, it is brought into contact with this liquefaction quickly and gelled to form a low boiling material. The gelling agent is preferably used in the form of being dissolved in a solvent of the same kind as the dehydrating solvent so that the gelling agent can be compatible or dispersed in the dehydrating solvent containing the.

The method of refluxing a part of the condensate for use in the gelation inhibitor solution is not particularly limited, and a conventionally known method (means) can be appropriately used. A specific example is shown below.

(1) When a dehydrating solvent is used in the esterification reaction and the dehydrating solvent is distilled out and refluxed, a part of the condensed residual liquid is extracted when returning the condensed residual liquid to the reaction tank, and the above nozzle is used. Can be directly supplied to the nozzle part to form an anti-gelling agent solution at the nozzle part, or can be mixed with the anti-gelling agent to form an anti-gelling agent solution during the supply to the nozzle part. . As a specific example, as shown in FIG. 2, which will be described later, the condensed residual liquid is returned to the reaction tank (preferably, the flange portion between the reaction tank and the rising line of the vapor) on the path for returning the condensed residual liquid as necessary. A storage unit (such as a tank) for temporarily storing is stored, and only a part of the condensed residual liquid is withdrawn from the stored unit, and a part of the condensed residual liquid extracted is joined to the gelation inhibitor supply path. The anti-gelling agent solution can be easily mixed with Therefore, a device for purposely mixing and stirring the both is unnecessary. Here, as a merit of providing the storage part, the adjustment is convenient when the withdrawal amount of the condensate residual solution for the gelation inhibitor solution is increased to a certain amount or gradually, and the condensate residual solution returned to the reaction tank is The point is that it is possible to easily adjust the amount to be refluxed from the start to the end of the reaction, always at a constant amount or while suppressing the increase amount as much as possible. Even if a storage unit such as a storage tank is not newly provided, for example, in a water separator, the condensate condensed and liquefied by a condenser is stored in one chamber and separated into two layers of a water phase and a solvent phase. The aqueous phase in the lower layer is sequentially withdrawn from the lower part of this chamber through a pipe, and the solvent phase in the upper layer overflows the partition plate and is stored in the other chamber next to it, but only the solvent phase is stored in the chamber. If it is made larger, the water separator itself can also serve as a storage unit (see FIG. 4).

However, the storage unit is not always necessary.
Compared with the case of using the conventional anti-gelling agent alone, for example, since the anti-gelling agent solution containing the condensation residual liquid is used, the amount of the anti-gelling agent is the same as or smaller than the conventional amount. The gelation prevention effect can now be exhibited.
Therefore, the increase in the amount of the solvent in the reaction tank is suppressed to the same level as or smaller than the conventional amount. Especially when the esterification time is short, the reaction temperature is not lowered so much and the influence on the reaction end time is small. Therefore, it is economically advantageous not to provide the storage section. Further, when the amount of the solvent returned to the reaction tank increases and increases, the solvent may be withdrawn to the outside of the system without returning the solvent partially to the reaction tank. Also in this case,
This is because the amount of solvent taken out of the system is not large and the processing cost thereof is low, so that it is economically advantageous compared to the case where a storage portion is provided, and does not affect the performance of the product. Thus, it can be said that it is important to appropriately determine whether or not to provide the storage unit in consideration of the influence on the performance and the cost-effectiveness.

(2) When the esterification reaction is carried out without using a dehydrating solvent, the distillate is essentially the reaction product water (containing a slightly low boiling point material), and the distillate is placed in the reaction tank. It does not bring part of it to reflux. Therefore, the whole amount or a part of the condensation residual liquid obtained by separating and removing the reaction product water (including the low boiling point raw material) from the condensate after the action of the gelation inhibitor solution on the distillate is withdrawn, and the nozzle part Can be directly supplied to the above-mentioned nozzle portion to form an anti-gelling agent solution, or while being supplied to the above-mentioned nozzle portion, it can be mixed with an anti-gelling agent to form an anti-gelling agent solution. When a part of the condensate residual liquid is used, the remaining condensate residual liquid may be drawn out of the system.

The above-described method of acting and the method of refluxing are merely representative ones, and the present invention is not limited to these.

In the present invention, the polymerization reaction of the low boiling point raw material (particularly (meth) acrylic acid) distilled along with the reaction product water in the distillation stage, particularly in the condensation stage is suppressed to prevent the reaction tank from flowing into the condenser. For the purpose of suppressing the formation of gel generated in the flange of the rising pipe, that is, the clogging of the condenser tube and the connecting pipe between the reaction tank and the condenser, the formation of gel-like substances derived from distillate is suppressed. An anti-gelling agent supply means for preventing may be provided separately.

As an example of the anti-gelling agent supplying means,
In order to directly act the anti-gelling agent on the distillate, the nozzle portion for spraying, blowing, spraying, ejecting, blowing up, or lowering the anti-gelling agent solution is used. A mode in which it is provided in at least one place on the pipe (overhead line) between the tank and the condenser can be mentioned. In this case, the spray nozzle may be provided, for example, in the condenser inside the condenser (particularly in the vicinity of the tower top), at the joint between the reaction tank and the rising line of the vapor (flange), or at the vapor line and the condenser tower top. There is a part where gel is likely to be formed, such as a flange part such as a flange part between them, a thermometer installed in a reaction tank or a projection part provided in the observation window, and among these, the condensation part inside the condenser ( Especially near the tower top),
A flange portion between the reaction tank and the rising line of the vapor and a flange portion between the vapor line and the top of the condenser are preferable.

Further, as the gelling inhibitor, the polymerization reaction at the distillation stage of the low boiling point raw material distilled along with the reaction product water, particularly at the condensation stage can be suppressed and the riser pipe from the reaction tank to the condenser can be suppressed. It is not particularly limited as long as it can suppress the formation of gel generated in the flange portion, that is, the clogging of the condenser tube or the connecting pipe between the reaction tank and the condenser, and various conventionally known gelation prevention It can be appropriately selected and used from the agents, and regarding specific examples and preferred embodiments (including the addition amount, the mode of action, the region to be acted on, and the type and amount of the solvent used in the case of the solution form), The same as with the above-mentioned gelation inhibitor.

More specifically, the following mechanism can be exemplified as an anti-gelling agent supplying means for preventing the generation of a gelled substance. In addition, the method of operation illustrated below is a representative example so that a person skilled in the art can easily understand the present invention, and the present invention is not limited thereto. Needless to say.

A) A gelling inhibitor is dissolved in a suitable solvent, preferably a solvent of the same kind as the dehydrating solvent to be charged into the reaction system to form a liquid, and the resulting product is a distillate containing reaction product water (preferably a solvent-water mixture). The area of condensation (as boiling material), specifically,
At the condensing part inside the condenser where the distillate containing the reaction product water is condensed and liquefied, preferably from the upper part of the condenser (particularly near the top of the column) to the inside thereof, the joint between the reaction tank and the rising line of the vapor. (Flange portion), the flange portion such as the flange portion between the vapor line and the condenser tower top portion, and the protrusion provided on the thermometer or the observation window installed in the reaction tank, It is a method of dripping or spraying so that they come into contact with each other in parallel flow. Depending on the type of capacitor, etc., a solution containing an antigelling agent may be charged inside the capacitor, and a gaseous distillate may be blown into it or a liquefied distillate may be poured into it to make contact (compatibility). Or it may be dispersed). Further, among the action sites of the above gelling agent, the condensation part inside the condenser (particularly in the vicinity of the tower top), the flange between the reaction tank and the rising line of the vapor, and the flange between the vapor line and the top of the condenser tower. Part is the site of action of the preferred anti-gelling agent. Further, the above-mentioned action site does not have to be one, and if necessary, a plurality of sites may be provided at the same time.

A) A powdered gelling agent is condensed in a region where the distillate containing the reaction product water is condensed, specifically, the condensation inside the condenser in which the distillate containing the reaction product water is condensed and liquefied. Part, preferably from the top of the condenser (especially near the top of the tower) to its interior, at the junction between the reactor and the rising line of the vapor (flange), at the flange between the vapor line and the top of the condenser tower. It is dropped or sprayed so as to come into parallel flow contact with the distillate on a flange portion such as the above and a projection portion provided on a thermometer or a peephole installed in a reaction tank or the like. Further, depending on the type of the capacitor and the like, an anti-gelling agent having a certain particle size may be loaded or filled in the capacitor in advance so as to be brought into contact therewith. Further, among the action sites of the above gelling agent, the condensation part inside the condenser (particularly in the vicinity of the tower top), the flange between the reaction tank and the rising line of the vapor, and the flange between the vapor line and the top of the condenser tower. Part is the site of action of the preferred anti-gelling agent. Further, the above-mentioned action site does not have to be one, and if necessary, a plurality of sites may be provided at the same time.

(C) Before the anti-gelling agent is vaporized (including sublimated ones) and the distillate (including low-boiling raw materials) containing gaseous reaction product water is condensed and liquefied, Inside the piping path that connects the container) and the condenser,
Condenser inside the condenser (especially near the tower top), joint between the reaction tank and the rising line of the vapor (flange), flange between the vapor line and condenser tower top, reaction tank, etc. At a site where gel is likely to be formed, such as a thermometer installed on the column or a projection provided on the observation window, preferably inside the condenser (particularly in the vicinity of the top of the column), between the reaction tank and the vapor rising line. It is supplied and mixed to the flange portion or the flange portion between the vapor line and the top of the condenser tower.

In the above embodiment, when the purpose is to suppress the formation of gel in the flange portion between the reaction tank and the rising line of the vapor, only the dehydrating solvent is used without the gelation inhibitor. The above object may be achieved by supplying to the flange portion. In the above case, the definition and specific examples of the dehydrating solvent are the same as those of the dehydrating solvent described below. In the above aspect, when used during the esterification reaction, the same kind of dehydrating solvent may be used, or different kinds of dehydrating solvents may be supplied to the flange portion. Further, when carrying out the esterification reaction in the absence of a dehydrating solvent, a dehydrating solvent supply mechanism may be separately provided, preferably near the flange, and the dehydrating solvent may be supplied to the flange.

Of the above modes, in the case of a),
Examples of the solvent capable of dissolving the gelation inhibitor include benzene, toluene, xylene, cyclohexane, acetone, methyl ethyl ketone, n-hexane, heptane, etc., but preferably, as described above, in the reaction system. It is preferable to use the same type of dehydration solvent as the one charged. When different solvents are used when refluxing and returning the solvent, if they are recovered separately, or when refluxing and returning, the heat transfer coefficient of the mixed solvent is the same as the heat transfer coefficient of the charged solvent. In that case, the control and management of the reaction system may become complicated, such as adjusting the amount of heat added to the reaction system so that the distillation amount (distillation rate) of the reaction product water does not fluctuate significantly. Therefore, it can be said that it is preferable to use the same solvent as the charged solvent.

Furthermore, when the above gelling inhibitor is dissolved in a solvent (preferably dehydrated solvent) to act, the gelling inhibitor can suppress the generation of gelled substances,
For the low boiling point raw material (gas or liquefied material) that passes through the condenser, the anti-gelling agent should always be present and supplied so as to function effectively. As a mixing ratio of the anti-gelling agent and the solvent Is not particularly limited, but the gelling inhibitor is usually added in an amount of 0.
The ratio is such that it is added in the range of 001 to 10 parts by mass, preferably 0.01 to 5 parts by mass. Mixing ratio is solvent 1
When the amount of the anti-gelling agent is less than 0.001 part by mass with respect to 00 parts by mass, the addition amount of the anti-gelling agent to be used is a constant amount with respect to the raw materials charged as defined above, As a result, the amount of solvent used (total amount added) increases, and the amount of solvent increases as it is sequentially refluxed with respect to the dehydrated solvent that was initially charged. Therefore, the amount of heat added to the reaction system must be adjusted. And the amount of water produced by the reaction (distillation rate)
It becomes necessary to complicate the control and control of the reaction system, such as the need to prevent large fluctuations. Also, when a solvent different from the dehydrated solvent is used and separated and recovered, the recovery cost increases. The cost will increase. On the other hand, when the mixing ratio exceeds 10 parts by mass of the gelling agent with respect to 100 parts by mass of the solvent, the amount of the solvent used (total amount to be added) decreases, so that the addition per unit time is reduced. The amount is limited, the frequency of contact with the low boiling point raw material is relatively reduced, and it becomes difficult to effectively suppress the formation of a gel-like substance by liquefying without contacting. Therefore, in order to secure the required amount of addition per unit time, a large amount of the gelling inhibitor above the amount specified above is required for the charged raw materials, which increases the manufacturing cost.

As described above, by separately providing the anti-gelling agent supply means, when continuous mass production is carried out, the gelled substance is attached or accumulated, so that the distilling path is blocked or the heat exchange efficiency is increased. It is possible to stably operate the esterified compounds applicable to various monomers including the raw material monomer of the high-performance cement dispersant for a long period without causing the total condensation failure due to the decrease of Also, it can be maintenance-free for a long time.

In the present invention, the method for producing an esterified product other than the above-mentioned requirements is not limited in any way, and a conventionally known method may be applied as it is or, if necessary, partially modified. It is possible. Below, among the methods for producing the esterified product of the present invention,
A preferred embodiment regarding requirements other than the requirements described above will be described in detail step by step.

As a preferred embodiment of the method for producing an esterified product other than the above-described requirements of the present invention, the following formula is used in the presence of a dehydrating solvent, an acid catalyst and a polymerization inhibitor:

[0076]

[Chemical 12]

In the method for producing an esterified product by the esterification reaction of an alcohol and (meth) acrylic acid represented by, the water produced by the reaction during the esterification reaction is distilled off together with a dehydrating solvent, and the water produced by the reaction and the dehydrated water are dehydrated. While the distillate containing a solvent is condensed and liquefied, the reaction product water is separated and removed from the condensed liquefied condensate, and the condensation residual liquid containing the dehydrated solvent after the reaction product water is separated and removed is returned to the reaction tank. Perform an esterification reaction (esterification step), and after completion of the esterification reaction, neutralize all of the acid catalyst or acid catalyst and part of (meth) acrylic acid (partial neutralization step), and then dehydrate from the reaction solution. This is a method of azeotropically distilling off a solvent with water (solvent distillation step) to obtain a target esterified product.

First, a preferred embodiment of the esterification step will be described below.

First, an alcohol of the formula (1) and (meth) acrylic acid as raw materials, preferably a dehydrating solvent, an acid catalyst and a polymerization inhibitor are charged into a reaction vessel, and the mixture is mixed with a predetermined ester at a predetermined temperature. The esterification reaction is performed until the conversion rate is reached. At this time, the reaction product water generated during the esterification reaction is distilled out together with the dehydration solvent, the distillate containing the reaction product water and the dehydration solvent is condensed and liquefied, and the reaction product water is separated and removed from the condensed liquefied condensate. Then, the condensate residual liquid after separating and removing the water produced by the reaction is refluxed and returned to the reaction tank (hereinafter, a system for performing a series of these operations is also referred to as a circulation system).

The alcohol used as a raw material for the ester reaction according to the present invention is a compound represented by the following formula (1).

[0081]

[Chemical 13]

In the above formula (1), R¹Is a carbon atom
It represents a hydrocarbon group of the number 1 to 30. R¹Has 3 carbon atoms
When the number of hydrocarbon groups exceeds 0,
For example, an esterified product of coal and (meth) acrylic acid
For example, a copolymer obtained by copolymerizing with (meth) acrylic acid
Water solubility decreases, and application performance such as cement dispersibility
Noh, etc. are reduced. Suitable R¹The range of
More different, for example, the raw material for cement dispersants
When used as¹Has 1 to 18 carbon atoms
Straight or branched chain alkyl and aryl groups
Is preferred. R ¹Specifically, for example,
Group, ethyl group, n-propyl group, isopropyl group, n
-Butyl group, tert-butyl group, pentyl group, hex
Group, octyl group, nonyl group, 2-ethylhexyl group,
Decyl group, dodecyl group, undecyl group, tridecyl group,
Tetradecyl group, pentadecyl group, hexadecyl group,
Putadecyl group, octadecyl group, nonadecyl group, eico
Alkyl such as syl, heneicosyl and docosyl
Group; aryl group such as phenyl group; benzyl group, nonyl
Alkylphenyl group such as phenyl group; cyclohexyl
Groups such as cycloalkyl groups; alkenyl groups; alkynyl
Groups and the like. Of these, the cement dispersant
When used as a raw material, as described above, methyl
Group, ethyl group, propyl group, butyl group, phenyl group are preferred.
It is a good thing.

R ² O is an oxyalkylene group having 2 to 18 carbon atoms, preferably 2 to 8 carbon atoms. When R ² O is an oxyalkylene group having more than 18 carbon atoms, an esterified product of the alcohol of formula (1) and (meth) acrylic acid is obtained, for example, by copolymerizing with (meth) acrylic acid. The water solubility of the copolymer is reduced,
The application performance, for example, the cement dispersion performance, is deteriorated. R
Examples of ² O include an oxyethylene group, an oxypropylene group, an oxybutylene group and an oxystyrene group, and among these, an oxyethylene group, an oxypropylene group and an oxybutylene group are preferable. The repeating units of R ² O may be the same or different. Among them, when the R ² O repeating units are different, that is, when two or more different repeating units are included, each R ² O repeating unit may be added in a block form or in a random form. May be.

Further, n is 0 to 300, preferably 2 to
It is a number of 300 and represents the average number of added moles of repeating units of R ² O (oxyalkylene group). When n exceeds 300, the polymerizability of the esterified product of the compound of formula (1) and (meth) acrylic acid decreases. This average addition mole number n also has a different optimum range depending on the purpose of use of the esterified product obtained by the esterification reaction. For example, when used as a raw material for a cement dispersant, the average addition mole number n n is preferably a number of 2 to 300, more preferably 5 to 200, and most preferably 8 to 150. When used as a thickener or the like, the average addition mole number n is preferably 10 to 250, more preferably 50 to 200. When n = 0, R ¹ is preferably a hydrocarbon group having 4 or more carbon atoms, from the viewpoint of water solubility and boiling point. That is, when n = 0 in the formula (1), particularly alcohols such as methanol and ethanol have a low boiling point, so that they evaporate together with the generated water and dissolve in the generated water, so that a part of the alcohol raw material is distilled out of the system. This is because the yield of the target esterified product is reduced.

In the production method of the present invention, the above formula (1)
As the alcohol raw material represented by, one kind may be used alone, or two or more kinds may be used in the form of a mixture. The usage form of the mixture of two or more alcohol raw materials represented by the formula (1) is not particularly limited, and R
^At least ^one of R ¹ , O ^{2 and} n is different 2
It may be used in a mixture of one or more kinds, but preferably when R ¹ is composed of two kinds of a methyl group and a butyl group; R ² O is composed of two kinds of an oxyethylene group and an oxypropylene group When n is composed of two kinds, that is, n is 1 to 10 and 11 to 100;

Regarding the (meth) acrylic acid that can be used in the ester reaction according to the present invention, acrylic acid and methacrylic acid may be used alone or in combination, and the mixing ratio thereof may be used. With respect to, an arbitrary range can be adopted.

The mixing ratio of the above raw materials used in the esterification reaction according to the present invention is stoichiometrically 1: 1 (molar ratio), but in practice, the alcohol and the (meth) acrylic acid are mixed. It is not particularly limited as long as the esterification reaction proceeds efficiently, but usually one of the raw materials is used in excess to accelerate the esterification reaction, or from the aspect of purification of the target esterified product, distillation is performed. Excessive use is made of lower boiling materials that are easily distilled off. Further, in the present invention, when the reaction product water and the dehydrating solvent are azeotropically distilled during the esterification reaction, a part of the low-boiling point (meth) acrylic acid is also distilled out and taken out of the reaction system. It is preferable to add the amount of (meth) acrylic acid used (the amount of charge) to the amount (the amount of charge) in excess of the amount calculated stoichiometrically. Specifically, the amount of (meth) acrylic acid used is usually 1.0 to 30 mol, preferably 1.2 to 10 mol, and more preferably 1.5 to 1 mol, based on 1 mol of alcohol.
It is 0 mol, most preferably 2 to 10 mol. (Meta)
The amount of acrylic acid used is 1.0 per mole of alcohol
If it is less than molar, the esterification reaction does not proceed smoothly,
The yield of the desired esterified product is insufficient, and conversely 3
If it exceeds 0 mol, no improvement in yield commensurate with the addition is recognized, and it is uneconomical, which is also not preferable.

In the esterification reaction of the present invention, if necessary, an acid catalyst may be added to the reaction system, but since the reaction can proceed rapidly, it can be carried out in the presence of an acid catalyst. It is desirable to carry out the reaction. Examples of the acid catalyst that can be used in this case include sulfuric acid, methanesulfonic acid, paratoluenesulfonic acid, paratoluenesulfonic acid hydrate, xylenesulfonic acid, xylenesulfonic acid hydrate, naphthalenesulfonic acid, naphthalenesulfone. Acid hydrate, trifluoromethanesulfonic acid, "Na
fion "resin," Amberlyst 15 "resin, phosphotungstic acid, phosphotungstic acid hydrate,
Examples thereof include hydrochloric acid. In this case, the acid catalyst may be used alone or in the form of a mixture of two or more kinds.

Of these, the acid catalyst preferably has a high boiling point at normal pressure, taking into consideration the azeotropic temperature of the dehydrating solvent and water, the esterification reaction temperature, etc., which will be described in detail below. Specifically, the boiling point of the acid catalyst preferably used in the present invention at atmospheric pressure is 150 ° C. or higher, more preferably 200 ° C. or higher. Therefore, sulfuric acid (boiling point at normal pressure: 317 ° C.), paratoluenesulfonic acid (boiling point:
185-187 ° C / 13.3Pa (0.1mmH
g)), paratoluenesulfonic acid hydrate and methanesulfonic acid (boiling point: 167 ° C./1333.2 Pa (10 mm
Hg)) and the like are preferably used. Furthermore, the present inventors have found that one of the causes of formation of an impurity diester that causes deterioration of the quality and performance of an esterified product is due to cleavage of an alkoxypolyalkylene glycol, and the cleavage also occurs by an acid catalyst. I got to know. Based on such findings, the inventors have found that the acid catalyst that is difficult to cleave is more desirable. In consideration of the above points, as the acid catalyst particularly preferably used in the present invention, paratoluenesulfonic acid and paratoluenesulfonic acid hydrate can be exemplified.

In the above embodiment, the amount of the acid catalyst used is not particularly limited as long as it can effectively exhibit a desired catalytic action, but is preferably 0.4 meq / g or less. Yes, more preferably 0.36-0.
01 meq / g, particularly preferably 0.32-0.05
It is within the range of milliequivalent / g. The amount of acid catalyst used is 0.4
If it exceeds milliequivalent / g, the amount of diester formed in the reaction system during the esterification reaction increases, and the esterification product obtained by the esterification reaction [alkoxy polyalkylene glycol mono (meth) acrylic acid] is used for synthesis. The cement dispersibility of the used cement dispersant decreases. Here, the amount of the acid catalyst used (milliequivalent / g) is the number of equivalents of H + (milliequivalent) of the acid catalyst used in the reaction, and the total amount of the raw material alcohol and (meth) acrylic acid charged (g )
It is expressed as the value divided by. More specifically, it is a value calculated by the following formula.

[0091]

[Equation 1]

In the present invention, the acid catalyst may be added to the reaction system all at once, continuously or sequentially, but from the standpoint of workability, it is preferred to charge the reaction vessel together with the raw materials at once. preferable.

Alternatively, in the present invention, when the esterification reaction is carried out in the presence of an acid catalyst, the acid catalyst is used as a hydrate and / or
Alternatively, it may be used in the form of an aqueous solution.

Examples of the acid catalyst that can be used in the above embodiment include sulfuric acid, methanesulfonic acid, paratoluenesulfonic acid, xylenesulfonic acid, naphthalenesulfonic acid, trifluoromethanesulfonic acid, "Naf
ion resin, “Amberlyst 15” resin, phosphotungstic acid, hydrochloric acid and the like in the form of a hydrate and / or an aqueous solution, among which sulfuric acid, paratoluenesulfonic acid, methanesulfonic acid and the like are used. Those used in the form of solvates and / or aqueous solutions are preferably used. These may be used alone or in combination of two or more. Further, as described above, the present inventors have found that one of the causes of the formation of the diester of impurities, which causes the deterioration of the quality and performance of the esterified product, is due to the cleavage of the alcohol raw material, and the cleavage is caused by the acid catalyst. Based on such knowledge, it was found that the acid catalyst that is difficult to cleave is more desirable. As the acid catalyst, specifically, paratoluenesulfonic acid is used in the form of a hydrate and / or an aqueous solution.

The amount of the acid catalyst used according to the above embodiment is not particularly limited as long as it can effectively exhibit the desired catalytic action, but it is effective for suppressing the cleavage action of the alcohol raw material and for various purposes such as, for example, , Cement dispersant, calcium carbonate, carbon black, pigment dispersant such as ink, scale inhibitor, gypsum / water slurry dispersant, CW
Usefulness as an esterified product as a raw material of a polymer component used as a dispersant for M, a thickener, and the like, and causes a bad influence on the dispersion performance which is the basic performance required for such usage. Considering prevention / suppression of gel generation that causes generation of a high-molecular-weight crosslinked polymer having poor dispersion performance, the amount of the acid catalyst used depends on the total amount of the raw material alcohol and (meth) acrylic acid in the acid catalyst. When the ratio of the mass of the acid is X (mass%) and the ratio of the mass of water present as a hydrate and / or an aqueous solution in the acid catalyst is Y (mass%), 0 <Y <1. It is preferable to satisfy the relationship of 81X-1.62. If there is no misunderstanding, a specific example will be described. For example, in the case of paratoluenesulfonic acid monohydrate, the ratio of the mass of paratoluenesulfonic acid to the total mass of the raw materials is X (mass%). )
And the ratio of the mass of the water present as a monohydrate to the total mass of the raw materials is Y (mass%), and the acid component other than the acid catalyst (for example, (meth) acrylic acid of the raw materials) is never used. Etc.) and water (for example, water produced by the esterification reaction) cannot be the objects of X and Y here.

At this time, if the amount of the acid catalyst used does not satisfy the above equation, the following problems occur. That is, when Y = 0, there is no water present as a hydrate and / or an aqueous solution in the acid catalyst, the amount of gel formed in the reaction system during the esterification reaction increases, and The application performance of the cement dispersant or the like synthesized by using the esterified product obtained by the chemical reaction, for example, the cement dispersibility is reduced. Also, Y ≧ 1.81
When it becomes X-1.62, the amount of gel formed in the reaction system during the esterification reaction increases, and the application performance of the cement dispersant or the like synthesized by using the esterified product obtained by the esterification reaction. For example, cement dispersibility and the like decrease.

In the above embodiment, the acid catalyst may be added to the reaction system all at once, continuously or sequentially.
From the standpoint of workability, it is preferable to charge the reaction vessel together with the raw materials.

The esterification reaction according to the present invention may be carried out in the presence of a polymerization inhibitor, if necessary. The use of the polymerization inhibitor can prevent the polymerization of alcohol, (meth) acrylic acid, or a mixture thereof as a raw material. Therefore, it is desirable to carry out the esterification reaction in the presence of the polymerization inhibitor. As the polymerization inhibitor that can be used in the present invention, known polymerization inhibitors can be used and are not particularly limited. For example, phenothiazine, tri-p-nitrophenylmethyl, di-p-fluorophenylamine. , Diphenylpicrylhydrazyl, N- (3-N-oxyanilino-1,3-dimethylbutylidene) aniline oxide, benzoquinone, hydroquinone, methoquinone, butylcatechol, nitrosobenzene, picric acid, dithiobenzoyl disulfide, cuperone, copper chloride (II) and the like. Of these, phenothiazine, hydroquinone and methoquinone are preferably used because of their solubility in dehydrated solvents and produced water. These polymerization inhibitors may be used alone or in combination of two or more.

When the acid catalyst is used in the form of a hydrate and / or an aqueous solution as described above, phenothiazine effectively functions also on the gel-forming substance in the aqueous solution existing in the reaction system. In addition, as will be described later, when the dehydration solvent is distilled off by azeotropic distillation with water after the completion of the esterification reaction, a water-soluble polymerization inhibitor such as hydroquinone or metoquinone having weak but polymerization activity is used. Even without using it, it is possible to exert the polymerization inhibition ability extremely effectively,
It is extremely useful because it can effectively suppress the formation of high molecular weight products.

According to the method of the present invention, when the polymerization inhibitor is used, the amount of the polymerization inhibitor to be used is 0. 1 with respect to the total amount of the alcohol and (meth) acrylic acid as raw materials charged.
It is in the range of 001 to 1% by mass, preferably 0.001 to 0.1% by mass. When the amount of the polymerization inhibitor used is less than 0.001% by mass, the polymerization inhibition ability is not sufficiently expressed, and the polymerization of alcohol as a raw material, (meth) acrylic acid, an esterified product as a product or a mixture thereof is performed. Is difficult to prevent effectively, and when the amount of the polymerization inhibitor used exceeds 1% by mass, the amount of the polymerization inhibitor remaining in the esterified product as a product increases, which is not preferable in terms of quality and performance. Further, no further effect commensurate with the excessive addition is obtained, which is not preferable from the economical point of view. Further, in a preferred embodiment using a dehydrating solvent, in the circulation system, the gelation inhibitor solution that acts on the distillate is also returned to the reaction tank, so the polymerization inhibitor in the gelation inhibitor solution is also Since it gradually accumulates in the reaction tank,
It is recommended to keep the polymerization inhibitor charged in the reaction tank within the range specified above.

Furthermore, in the present invention, it is desirable to carry out the esterification reaction in the presence of a dehydrating solvent from the viewpoint that it is desirable to be able to distill the reaction product water from the reaction tank at a lower temperature from the viewpoint of handling. . In the present specification, the dehydration solvent is defined as a solvent that is azeotropic with the water produced by the reaction. That is, by using the dehydrating solvent, the reaction product water generated by the esterification reaction can be efficiently azeotropically distilled. As the dehydrating solvent, for example, benzene, toluene, xylene, cyclohexane,
Examples thereof include dioxane, pentane, hexane, heptane, chlorobenzene, and isopropyl ether. These can be used alone or in combination of two or more as a mixed solvent. Of these, the azeotropic temperature with water is 1
It is preferably 50 ° C. or lower, more preferably in the range of 60 to 90 ° C., and specific examples thereof include cyclohexane, toluene, dioxane, benzene, isopropyl ether, hexane, heptane and the like. When the azeotropic temperature with water exceeds 150 ° C., it is not preferable from the viewpoint of handling (including temperature control in the reaction tank at the time of reaction and control such as condensation liquefaction treatment of the azeotrope).

It is desirable that the dehydration solvent is azeotropically distilled with the reaction product water outside the reaction system, and the reaction product water is condensed and liquefied to be refluxed while being separated and removed. 1 to 100% by mass, preferably 2 based on the total amount of alcohol and (meth) acrylic acid charged.
It is within the range of 50% by mass. When the amount of the dehydrating solvent used is less than 1% by mass, the reaction product water generated during the esterification reaction cannot be sufficiently removed out of the reaction system by azeotropy, and the equilibrium reaction of esterification is difficult to proceed, which is preferable. Without
When the amount of the dehydrating solvent used exceeds 100% by mass, the effect commensurate with the excessive addition cannot be obtained, and a large amount of heat is required to keep the reaction temperature constant, which is preferable from the economical viewpoint. Absent.

In the esterification reaction according to the present invention, when a dehydrating solvent is used, the reaction temperature during the esterification reaction is 30 to 130 ° C., more preferably 60 to 130 ° C.
And the solvent circulation rate during the esterification reaction is 0.5
Cycles or more / hour, more preferably 1 to 100 cycles / hour or more. Thereby, it is not necessary to raise the reaction temperature to the impurity formation temperature region (region above 130 ° C.) to cause the reaction, and it is possible to suppress the formation of impurities in the reaction tank. Also, by increasing the solvent circulation speed, the reaction product water can be efficiently azeotropically distilled from the reaction tank without staying in the reaction tank for a long period of time, and the equilibrium reaction proceeds in the direction of esterification. It can be shortened.

In the present specification, the solvent circulation rate during the esterification reaction is defined as follows. That is, with respect to the total amount (volume amount) of the dehydrated solvent charged in the reaction tank, during the esterification reaction, the dehydrated solvent in the reaction tank is circulated again from the reaction tank to the reaction tank through the circulation path to circulate the reaction tank. When the amount (volume amount) equivalent to the total amount of the dehydrated solvent charged in the above is circulated as one cycle, the solvent circulation rate during the esterification reaction is
It shall be represented by the said number of cycles per time), and the unit shall be "cycle / hour". Therefore, for example, when 5 times the amount equivalent to the total amount of the dehydrated solvent charged in the reaction tank is circulated in 5 hours, the solvent circulation rate is 3 cycles / hour. Similarly,
In 2 hours, to the total amount of dehydrated solvent charged to the reaction system,
When half the amount equivalent to this (0.5 times) is circulated, the solvent circulation rate is 0.25 cycles / hour. Here, the dehydrated solvent in the reaction system is distilled out from the reaction system, condensed and liquefied, and is circulated when it is circulated back to the reaction system (the object to be circulated) includes the dehydrated solvent and its embodiment. Depending on the amount, a small amount of low boiling point raw material (mainly (meth) acrylic acid raw material) is distilled out, and added in order to prevent the distilling raw material from forming a gel and becoming a harmful impurity. Various additives such as anti-gelling agent (polymerization inhibitor or solvent containing the polymerization inhibitor, etc.) may be contained. Therefore, when an additive such as an anti-gelling agent is used, it is desirable to appropriately adjust the setting conditions in consideration of the fact that the solvent circulation rate fluctuates as the esterification reaction proceeds.

The reaction temperature and the solvent circulation rate are the heating method (means) for the reaction tank and the temperature (heat quantity) applied to the reaction tank using the apparatus, and the amount of dehydrated solvent used for the raw materials charged in the reaction tank. Can be adjusted to a desired range. The reaction temperature is the maximum (MAX) temperature in the reaction tank. That is, the temperature inside the reaction tank (reaction temperature) depends on the mode of the device used as the heating means (eg, outer jacket, inner heater, etc.).
Varies depending on the position, but also rises as the esterification reaction progresses and fluctuates with the passage of time, but since the reaction temperature rises, impurities are formed. However, since it is necessary that the upper limit temperature defined above is not exceeded at any position and at any time, the maximum temperature is defined here.

The esterification reaction according to the present invention may be carried out without a solvent without using a dehydrating solvent. In this case, a gas such as air or an inert gas (nitrogen gas, helium gas, argon gas, carbon dioxide) (preferably a gas containing no water vapor) is used as the reaction liquid in order to remove the generated reaction product water. It is necessary to carry out the bubbling process. As such bubbling treatment, for example, a gas (bubble) is continuously blown out into the reaction solution from an air nozzle or the like provided in the lower part of the reaction tank, and water in the reaction solution is bubbled in the process of passing through the reaction solution ( The steam-containing gas that has been taken into the bubble and has passed through the reaction solution is distilled out from the reaction tank (preferably, the steam contained in the distilled distillate (water-vapor containing gas) is liquefied and removed, The method of circulating the dried gas again) can be exemplified, but the method is not particularly limited to this, and conventionally known bubbling treatment methods can be appropriately selected and used in combination as necessary. Therefore, the flow rate of air used in the bubbling process is required according to the amount (rate) of the generated reaction product water so that the reaction product water that is sequentially generated does not stay in the reaction tank for a long time. It suffices to continuously supply various air flow rates. Further, as the gas, it is preferable to supply the gas heated to the same temperature as the reaction liquid temperature so that the temperature in the reaction tank does not change. In the present embodiment, when the distillate (water vapor-containing gas) distilled out of the reaction system is liquefied by the condenser, the gelation inhibitor solution may be applied.

In the present invention, the esterification reaction may be carried out batchwise or continuously, but it is preferably carried out batchwise.

The reaction conditions for the esterification reaction may be such that the esterification reaction proceeds smoothly, and the reaction temperature is 30 to 140 ° C., preferably 60 to 13
The temperature is 0 ° C, more preferably 90 to 125 ° C, and particularly preferably 100 to 120 ° C. The reaction temperature is a condition for a general esterification reaction of the present invention, in which a dehydration solvent is azeotropically distilled with the reaction product water outside the reaction system, and the reaction product water is condensed and liquefied to be refluxed while being separated and removed. This is one of the cases, and it is included in these ranges, but it is not an exact match. When the reaction temperature is lower than 30 ° C., the esterification reaction is difficult to proceed, and it takes time to dehydrate (distill) the reaction product water. Further, the reflux of the dehydrating solvent is slow and the dehydration takes a long time. It is not preferable because the time required for the reaction becomes long. On the other hand, when the reaction temperature exceeds 140 ° C., an excessive amount of diester is produced due to the cutting of the alcohol raw material, and in addition to the cement dispersion performance, the dispersion performance and the thickening property in various applications are deteriorated. In addition, polymerization of the raw material occurs, the amount of the raw material mixed in the distillate increases, and the performance and quality of the esterified product, which is the product, deteriorates.
After all it is not preferable. The reaction time is usually 1 to 50 hours, preferably 3 to 40 hours, although the esterification rate reaches at least 70%, preferably at least 80% as described later. Furthermore, the esterification reaction according to the present invention may be carried out either under normal pressure or under reduced pressure, but it is desirable to carry out under normal pressure from the viewpoint of equipment.

The esterification rate in the esterification reaction according to the present invention is 70% or more, more preferably 70 to 99.
%, And most preferably 80 to 98%. When the esterification rate is less than 70%, the yield of the produced esterified product is insufficient, and the application performance of the cement dispersant or the like obtained using this as a raw material, for example, the cement dispersibility is deteriorated. The "esterification rate" used in the present specification is a value calculated by the following formula by measuring the decrease amount of alcohol as a starting material for esterification under the esterification measurement conditions shown below. It is defined.

[0110]

[Equation 2]

Esterification rate measurement conditions Analytical apparatus: Waters Millennium Chromatography Manager Detector: Waters 410 RI detector Column used: GL Science Inertosyl ODS-2 3 columns Temperature: 40 ° C Eluent: Water 8946g Acetonitrile 6000 g acetic acid 54 g was mixed and adjusted to pH 4.0 with 30 mass% sodium hydroxide aqueous solution Flow rate: 0.6 ml / min Since the esterification rate was determined by the above formula, the esterification rate was 100%. It cannot be exceeded. Therefore, in the present invention, it is assumed that the esterification reaction is completed when the esterification rate reaches or exceeds the regulation.

An embodiment of the method for producing an esterified product according to the present invention will be described with reference to FIG.

FIG. 1 is a schematic view of an embodiment of the apparatus configuration used in the method for producing an esterified product according to the present invention.

As shown in FIG. 1, in the apparatus configuration of the present embodiment, first, pressure steam or the like is used as a heating means (for example, a direct heating method such as an internal heater or an indirect heating method such as an external jacket) for carrying out the esterification reaction. There is provided a reaction tank 101 having an outer jacket 102 which uses as a heat medium. At this time, the material inside the reaction tank is not particularly limited, and known materials can be used. For example, SUS, preferably SUS304, SUS316 and SUS316L from the viewpoint of corrosion resistance, more preferably SUS316 and SU.
S316L is mentioned. Alternatively, the inside of the reaction vessel may be subjected to a glass lining process or the like so as to be inert to the raw materials and products. In the reaction vessel 101, stainless steel (for example, SUS31
6) a raw material storage tank 103 and a raw material storage tank 105 for (meth) acrylic acid, a catalyst storage tank 107 for a reactive acid catalyst, and a polymerization inhibitor for preventing polymerization in the reaction system (reaction tank 101). Polymerization inhibitor storage tank 109 that has been stored and a neutralization agent storage tank made of carbon steel (for example, high carbon steel) that has stored a neutralizing agent (neutralizing agent aqueous solution) for neutralizing the catalyst after the esterification reaction 111 are connected by pipes 113, 115, 117, 119 and 121, respectively. Also, (meth) acrylic acid is easy to polymerize. For example, with methacrylic acid, a small amount of a polymerization inhibitor (0.1% hydroquinone, etc.) is added because it is polymerized by long-term storage, heat, etc. However, since it is easy to polymerize, when it is stored in the raw material storage tank 105, benzene may be added to prevent crystallization, and as shown in FIG. 1, a pump 116 is used to keep the temperature at 30 to 40 ° C. at all times.
A circulation path 151 having an outer jacket 150 (heat-retaining means) using the
You may hold | maintain at 0-40 degreeC and may circulate so that it may not superpose | polymerize. Raw material storage tank 105 for (meth) acrylic acid, piping 1
For the purpose of preventing corrosion due to corrosive (meth) acrylic acid, it is preferable to perform lining processing with a corrosion resistant material such as a synthetic resin inside the pump 15, the pump 116, and the circulation path 151. Similarly, inside the catalyst storage tank 107 and its pipe 117, for the purpose of preventing corrosion by an acid catalyst,
It is preferable to perform a lining process using an acid resistant material such as a synthetic resin. In the lower part of the reaction tank 101, an ester compound synthesized in the reaction tank 101 by an esterification reaction (or, in a cement dispersant or the like, the ester compound is further polymerized in the reaction tank 101 as a monomer component). A pipe 153 for collecting the polymer obtained by performing the above is connected. Further, if necessary, a temperature sensor (not shown) for measuring the reaction temperature in the reaction tank 101.
May be attached to an appropriate part (several places).
The temperature sensor is electrically connected to a control unit main body (not shown) for controlling an apparatus mechanism (for example, the temperature of the jacket 102 attached to the reaction tank 101) necessary for maintaining the reaction temperature at a specified temperature. Connected to each other.

Furthermore, in the apparatus configuration of the present embodiment, the distillate containing the reaction product water produced during the esterification reaction is distilled in the reaction system (reaction tank 101) to prevent the formation of gel-like substances. While condensing and liquefying, the reaction product water was separated and removed, and the reaction product water was azeotroped with a dehydrating solvent as a mechanism (device configuration) for returning the remaining distillate at a predetermined solvent circulation rate. The anti-gelling agent acts on the distillate to condense and liquefy, and the reaction product water (aqueous phase) from the condensed and liquefied distillate
Is separated and removed, and the remaining condensate (mainly the solvent phase containing the dehydrated solvent) is refluxed at the solvent circulation rate and returned to the reaction tank 101. Specifically, the upper portion of the reaction tank 101 and the tower top portion of a vertical multi-tubular circular tube type condenser 125 of countercurrent (or cocurrent) contact type are connected by a pipe 123.
Further, the lower bottom part of the condenser 125 and the upper part of the water separator 127 made of SUS are connected by a pipe 129. A vacuum pump (ejector) 155 is attached to the water separator 127 via a pipe 157 for distilling and removing a dehydrated solvent for isolating the esterified product after the esterification reaction. Further, a partition plate 131 is provided inside the water separator 127, and two chambers 133, 134 partitioned by the partition plate 131 are provided.
Are formed. Of these, the lower part of the chamber 133 on the side where the distillate condensed and liquefied by the condenser 125 is stored is connected to the reaction product water treatment tank 135 by a pipe 137. A pipe 139 for waste water is connected to the processing tank 135. Further, the lower part of the other chamber 134 of the water separator 127 and a storage tank 128 for temporarily storing the condensed residual liquid are connected by a pipe 141, and the storage tank 128 and the reaction tank 101 are connected by a pipe 148. Are connected by. Also, this piping 14
A pipe 145 connected to a dehydration solvent storage tank 143 that stores a dehydration solvent that is azeotropic with the reaction product water in the reaction tank 101 is joined (connected) to the tank 8. A circulation pump 142 is installed on the path of the pipe 148 before the confluence (on the side of the storage tank 128). Also, behind the confluence (reaction tank 101
A flow meter 144 is provided on the path of the (side) pipe 148. The flow meter 144 is electrically connected to a flow rate measurement system body (not shown) for integrating the measured flow rates and calculating the solvent circulation speed. In addition, the condensate residual liquid is stored in the condenser 125 on the other side of the storage tank 128.
A pipe 152 for supplying to the top of the tower is connected,
A pump 146 is installed on the path of the pipe 152.
Further, as described above, it is possible to supply an antigelling agent solution containing an antigelling agent and, if necessary, a solvent for dissolving the antigelling agent to the top of the condenser 125 in addition to the residual condensation liquid. For the purpose, an anti-gelling agent storage tank 147 for storing an anti-gelling agent and a solvent storage tank 159 for storing a solvent for dissolving the anti-gelling agent are respectively provided in pipe 149.
And 161 to join (connect) with each other through a pipe 154, and a mixed solution of an antigelling agent and a dehydrating solvent passes through the pipe 154. further,
This pipe 154 joins (connects) to the pipe 152 to form a pipe 156, in which a mixed solution of an antigelling agent and a dehydrating solvent and a condensation residual liquid are mixed to form an antigelling agent solution, and finally,
The anti-gelling agent solution is sprayed through the pipe 156 to the spray nozzle 1
It is supplied from 26 to the top of the condenser 125. Note that, although the spray nozzle is installed downward in FIG. 1, the direction of the spray nozzle is not particularly limited as long as it can supply the anti-gelling agent solution to a desired position, and description of FIG. As such, it may be upward.

In the present invention, the capacitor is S
SU such as US304, SUS316 and SUS316L
Known products such as S and carbon steel (CS) can be used,
Preferably, in order to further reduce the generation of gel, a capacitor whose inner surface is mirror-finished or glass-lined can be used, but in consideration of the cost of processing and maintenance, SUS304 (SUS2 in JIS standard)
7; hereafter, omitted), SUS316 (SUS32 in JIS standard; hereafter, omitted) and SUS316L (JIS
SUS33 in the standard; hereinafter omitted), preferably S
Capacitors made of SUS such as US316 and SUS316L can be preferably used, and even when such a capacitor is used, gel formation can be effectively prevented. Further, the heat transfer area of the condenser preferably used in the present invention varies depending on the volume of the reaction tank or the like, but for example, in the reaction tank 30 m ³ , it is 50 to 500 m ² , preferably 100 to
It is 200 m ² . In the present invention, examples of the cooling medium used for the condenser include water and oil.

In the method for producing an esterified product according to the present invention, the production process for an esterified product having the apparatus configuration according to the above-described embodiment is performed as follows.

First, inside the reaction tank 101, the raw material storage tanks 103 and 105, the catalyst storage tank 107, the polymerization inhibitor storage tank 109, and the dehydrated solvent storage tank 143 are connected to the pipes 113, 115 and 11.
The raw materials alcohol and (meth) acrylic acid, the acid catalyst, the polymerization inhibitor and the dehydrated solvent are fed in the respective prescribed amounts specified above (prepared) through 7, 119 and the pipe 148 through the pipe 145, and the above is specified. The esterification reaction is performed under esterification conditions (reaction temperature, jacket temperature, pressure). The reaction product water sequentially produced by the esterification reaction is azeotroped with the dehydrated solvent charged in the reaction tank 101, and the pipe 1
Distilled through 23. The solvent-water azeotrope that is the distilled gas fluid is passed through the condenser 125 and condensed and liquefied. In order to prevent the low boiling point raw material contained in the azeotrope from gelling during this condensation and liquefaction, from the spray nozzle 126 provided at the top of the condenser 125 through the pipe 149 from the gelling agent storage tank 147. The amount of anti-gelling agent specified above is continuously added dropwise and brought into cocurrent contact with the azeotrope (refers to both gas fluid and condensed liquefaction).
The condensed and liquefied azeotrope (including the dropped anti-gelling agent) is stored in the chamber 133 of the water separator 127 through the pipe 129 from the lower part of the condenser 125 and separated into two layers of water phase and solvent phase. To be done. Of these, the reaction product water in the lower layer is sequentially withdrawn from the lower part of the chamber 133 through the pipe 137 and stored in the reaction product water treatment tank 135. Then, in the treatment tank 135, if necessary, after being chemically or biologically treated so as to satisfy the environmental standard (wastewater standard) value, the pipe 139
Through, it is discharged to the outside of the system. On the other hand, the solvent phase of the upper layer (= condensation residual liquid; in addition to the dehydrated solvent, the gelation inhibitor solution and the low boiling point raw material) overflows the partition plate 131 and is stored in the adjacent chamber 134. Then, the solvent phase is temporarily stored in the storage tank 128 from the lower portion of the chamber 134. Of the condensation residual liquid stored in the storage tank 128, the amount of the condensation residual liquid required to make up for the reduced amount of dehydrated solvent distilled from the reaction tank 101 is defined by the pump 142 through the pipe 148 as described above. The reaction tank 10 is refluxed at the solvent circulation rate
Set back to 1. Further, a part of the condensation residual liquid stored in the storage tank 128 is sequentially extracted through the pipe 152 by the pump 146 as described above, and if necessary, from the gelation inhibitor storage tank 147 and the solvent storage tank 159. Plumbing 14 each
9 and 161 are mixed with an anti-gelling agent and a solvent to form an anti-gelling agent solution, and the anti-gelling agent solution is passed through a pipe 156 from a spray nozzle 126 to a top portion of a condenser 125. Is supplied to. As mentioned above,
For a while after the start of the reaction, the storage tank 128 does not sufficiently store the residual condensate that can be used to form the gelling agent solution, so gelation is prevented until the storage tank 128 is sufficiently stored. Only the agent solution is piped 149, respectively from the anti-gelling agent storage tank 147 and the solvent storage tank 159.
161, then supply to the spray nozzle 126 via the pipe 154, and further via the pipe 156 to spray onto the top of the condenser 125,
Alternatively, a minimum amount of dehydrating solvent necessary for forming the gelling agent solution (or a dehydrating solvent containing an appropriate amount of gelling agent) is charged in the storage tank 128 in advance, and the spray nozzle 126 is operated in the same manner as above from the initial stage of the reaction. You may make it spray to the tower top part of the condenser 125 through.

In the present invention, the anti-gelling agent storage tank installation site for supplying the anti-gelling agent is preferably a site where gel is easily formed, but is not particularly limited.
For example, in addition to the embodiment in FIG. 1, that is, the embodiment in which the spray nozzle 126 for spraying the gelling inhibitor is provided at the top of the condenser 125, the pipe 12 between the reaction tank 101 and the condenser 125 is added.
A mode in which a spray nozzle for spraying an anti-gelling agent is provided in at least one place on 3 is mentioned. In the latter embodiment, the spray nozzle for spraying the anti-gelling agent on the pipe 123 may be provided, for example, as a condensing part inside the condenser (particularly in the vicinity of the top of the column), a joint between the reaction tank and the rising line of the vapor. Parts (flange parts), flange parts such as the flange part between the vapor line and the top of the condenser tower, thermometers installed in reaction tanks and projections provided in the peepholes Of these, the condensation part inside the condenser (particularly in the vicinity of the tower top), the flange portion between the reaction tank and the vapor rising line, and the flange portion between the vapor line and the condenser tower top are preferable.

After completion of the esterification reaction (finished when the esterification rate reaches or exceeds a specified value), the neutralizing agent storage tank
An aqueous solution of a neutralizing agent is added to the reaction tank 101 through a pipe 121 from 111 to neutralize the acid catalyst, and the dehydrated solvent (and excess (meth) acrylic acid) is distilled off azeotropically with water under normal pressure. , Isolate the desired esterified product. In the case of distilling the dehydrating solvent and the excess (meth) acrylic acid,
After distilling the distillate containing the reaction product water generated during the esterification reaction in the reaction system (reaction tank 101) and condensing and liquefying while preventing the formation of a gel, the reaction product water is separated and removed. However, it can be carried out by using a part of (a device configuration of) a mechanism for refluxing the remaining distillate. In this case, it is necessary to remove the dehydrated solvent (including excess (meth) acrylic acid in the case of isolation without polymerization subsequently) to the outside of the system without reflux, and therefore the water separator 127 It is taken out of the system using a vacuum pump (ejector) 155 attached to the. In addition, these may be discarded or may be chemically treated and reused using an apparatus outside the system. On the other hand, the obtained esterified product is recovered from the pipe 153. When used for the synthesis of a cement dispersant or the like, the obtained esterified product is used as one of the monomer components and further polymerized in the reaction tank 101 to obtain a polymer which can be a main composition component of the cement dispersant. You may make it synthesize | combine. In this case, it is preferable to use the unreacted (meth) acrylic acid that has been added in excess and remains as the other monomer component without being separated and removed.

The above has described one embodiment of the method for producing an esterified product of the present invention with reference to FIG. 1. However, the method for producing an esterified product according to the present invention is not limited to this embodiment. However, as long as it includes a step of causing the anti-gelling agent to act on the distillate, there is no limitation on the manufacturing method (means), apparatus configuration, etc., and conventionally known manufacturing methods, apparatus configurations, etc. It can be used in an appropriate combination.

The esterification reaction according to the present invention has been described above in detail. When the esterification reaction according to the present invention is carried out in the presence of an acid catalyst and in a dehydrated solvent, after the esterification reaction is completed, The acid catalyst or all of the acid catalyst detailed below and a part of the (meth) acrylic acid are neutralized (partial neutralization step), and then the dehydration solvent is azeotropically distilled with water from the reaction solution detailed below. It is desirable to obtain the desired esterified product by distilling off (solvent distilling step).

First, the partial neutralization step according to the present invention will be described. In the esterification step, when the ester reaction is carried out in the presence of an acid catalyst, it is desirable to carry out the partial neutralization step described below. That is, the present inventors, when adding water in the step of distilling the dehydration solvent after the esterification reaction for azeotropic distillation, or for further polymerization using the esterified product, add adjusted water after the ester reaction. When an aqueous solution of the produced esterification product is produced, hydrolysis by an acid catalyst occurs, which leads to deterioration of the quality and performance of the esterification product. In addition, what is produced by hydrolysis (hereinafter, also simply referred to as hydrolysis product) When the polymer remaining in the esterified product is used to synthesize a polymer used for various dispersants such as cement dispersants and thickeners, the hydrolysis product is involved in the polymerization. Not become impurities,
Since the polymerization rate (and eventually the productivity) is lowered, and the quality and performance of the polymer are also deteriorated, in order to solve such a problem, after completion of the esterification reaction in the above-mentioned esterification step, the acid is heated at 90 ° C. or lower. It has been found that it is desirable to neutralize the catalyst with alkali. As a result, a high-purity, high-quality esterified product can be obtained without producing a hydrolysis product in the treatment process after the esterification reaction.

Here, a preferred embodiment of the partial neutralization step will be described below.

In the partial neutralization step of the present invention, after completion of the esterification reaction, the acid catalyst is neutralized with alkali at 90 ° C. or lower, preferably in the range of 50 to 0 ° C.

When the neutralization temperature (liquid temperature of the reaction system) in the partial neutralization step is higher than 90 ° C., the added alkali acts as a catalyst for hydrolysis and a large amount of hydrolysis product is produced. It is not preferable because it is generated. Furthermore, 5
At 0 ° C. or lower, the alkali does not act as a hydrolysis catalyst, and the generation of hydrolysis products can be completely suppressed. On the other hand, when the temperature is lower than 0 ° C, the esterification reaction liquid becomes viscous, and stirring during neutralization becomes difficult,
It takes a long time to cool to a predetermined temperature after the esterification reaction, and to cool to a temperature lower than room temperature,
Since it is necessary to newly provide a cooling means (device), the cost is increased, which is not desirable.

The alkali (neutralizing agent) that can be used in the partial neutralization step is not particularly limited, and takes the form of hydroxide M (OH) _n and dissolves in water. , As long as it is a substance showing basicity, M in this case
Means an alkali metal, alkaline earth metal or ammonium group. Furthermore, alkali metal carbonates, phosphates, ammonia, amines, etc. are also included in the alkalis referred to herein. Therefore, as the alkali, specifically, for example, hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide, hydroxides of alkaline earth metals such as magnesium hydroxide and calcium hydroxide, ammonia, amine Examples thereof include hydroxides, carbonates, and phosphates of alkali metals or alkaline earth metals, because they do not give off a strange odor when mixed in cement. Further, in the present invention, these alkalis may be used alone or in combination of two or more at an appropriate ratio.

The acid neutralized with the alkali is an acid catalyst, preferably all of the acid catalyst and part of (meth) acrylic acid. Here, the neutralized (meth) acrylic acid is
The amount of (meth) acrylic acid used in the esterification reaction is 10% by mass or less, preferably 0.01 to 5% by mass. Therefore, the addition amount of the alkali (neutralizing agent) is
1.0-100 equivalents, preferably 1.0-
It is 10 equivalents, more preferably 1.01 to 2 equivalents.
The reason why the acid to be neutralized is the acid catalyst, as described above, the acid catalyst reacts strongly with the water added after the esterification reaction to form a hydrolysis product, which makes the acid catalyst inactive. This is because it is necessary. As the acid component,
(Meth) acrylic acid may be present in addition to the acid catalyst, but since the acid catalyst has higher acid strength, there is no problem because it is neutralized from the acid catalyst. Therefore, if the acid catalyst can be neutralized, the intended purpose can be achieved, but if the type of acid catalyst actually used is different (= difference in acid strength) or a large amount of industrial treatment is performed, the acid catalyst is Since a part of the (meth) acrylic acid may be neutralized before the total amount of (meth) acrylic acid is neutralized, the total amount of the acid catalyst and the (meth) acrylic acid is Part may be neutralized. However,
When the (meth) acrylic acid to be neutralized exceeds 10% by mass of the (meth) acrylic acid used in the esterification reaction, the polymerization rate of the (meth) acrylic acid salt is probably higher than that of the (meth) acrylic acid. It is not preferable because the polymerization rate at the time of polymerizing using the obtained esterified product is lowered because it is slow. If the amount of the alkali (neutralizing agent) added is less than 1.0 equivalent to 1 equivalent of the acid catalyst, the acid catalyst cannot be completely neutralized and a large amount of hydrolysis product is produced. Is not preferable. On the contrary, when the amount of the alkali (neutralizing agent) added exceeds 100 equivalents relative to 1 equivalent of the acid catalyst, a large amount of (meth) acrylic acid is neutralized, and
Since the polymerization rate of the (meth) acrylic acid salt is slower than that of the (meth) acrylic acid, the polymerization rate at the time of polymerizing using the obtained esterified product is not preferable.

The form of the alkali to be added is not particularly limited, but it can be said that the form of an aqueous alkali solution is preferable from the viewpoint of preventing hydrolysis of the esterified product.

In particular, since the esterification reaction is carried out in a dehydrated solvent, it is preferable to add a large amount of water together with the alkali to the reaction system in order to prevent hydrolysis of the esterified product. That is, in a reaction system without a large amount of water, the alkali is hardly soluble in the dehydrating solvent and therefore floats in the system in a concentrated state. Not causing hydrolysis of the esterified product. The amount of the water added depends on the use form of the alkali, but, for example, in the case of adding a 40 to 60% alkali aqueous solution as a neutralizing agent, 1 part by mass of the alkali aqueous solution is added separately from the alkali aqueous solution. Normally 5-10
The amount is 00 parts by mass, preferably 10 to 100 parts by mass. In this case, if the amount of water added is less than 5 parts by mass, the alkali becomes non-uniform in the reaction system due to the above reason, and the high concentration of alkali causes hydrolysis of the esterified product.
If the amount exceeds 100 parts by mass, a neutralization tank is additionally required to ensure productivity, resulting in high cost, which is not preferable.

Next, the solvent distillation step according to the present invention will be described below. That is, since the esterification reaction is carried out in a dehydration solvent, the dehydration solvent is distilled off from the reaction solution after the esterification reaction is carried out. Further, when the esterification reaction is carried out in the presence of an acid catalyst, after the esterification reaction is carried out by the esterification step, the acid catalyst, and further a part of (meth) acrylic acid is carried out by the partial neutralization step. Neutralization is carried out, and then the dehydrated solvent is distilled off from the reaction solution.

With respect to a preferred embodiment of the solvent removal step,
This will be described below.

According to a preferred embodiment of the solvent removal step, when the dehydration solvent is distilled off after completion of the esterification reaction (after partial neutralization treatment, if necessary), the dehydration solvent is removed. An anti-gelling agent acts on the distillate containing it. Thus, when the dehydration solvent is distilled off after the completion of the esterification reaction, a gel-like substance (poly ( (Meth) acrylic acid, etc.) itself can be effectively prevented, and a high-purity and high-quality esterified product can be obtained. In this aspect,
The distillate usually contains not only a dehydrating solvent but also raw materials, especially (meth) acrylic acid, which are distilled out together when the dehydrating solvent is distilled from the reaction tank.

In the above preferred embodiment, the gelling inhibitor used for distilling the dehydrated solvent after the esterification reaction and acting on the distillate containing the dehydrated solvent is a distillate. The unreacted low-boiling point raw material contained in is not particularly limited as long as it can suppress the polymerization reaction occurring at the stage of being condensed and liquefied, and similarly to the above, various conventionally known gelation prevention It can be appropriately selected and used from the agents, and its specific examples and preferable examples are the same as those for the above-mentioned gelation inhibitor.

The amount (addition amount) of the gelling inhibitor used at this time is, for example, the distillation temperature (calorific value) or the amount of dehydrating solvent used in the esterification reaction (and the water content added after the completion of the esterification). Amount corresponding to the amount of the unreacted low-boiling raw material distilled, that is, from the start of the distillation of the distillate containing the dehydrating solvent until the dehydrating solvent is sufficiently distilled off. It suffices that the unreacted low boiling point raw material is allowed to act in an amount that can effectively prevent the formation of a gelled substance, and the raw material alcohol of formula (1) and (meth) acrylic acid are used. It is usually 0.
1-1000 mass ppm, preferably 1-500 mass p
It is in the range of pm. 0.1 mass p for the amount of raw materials used
If it is less than pm, a gel-like material may be formed,
For the unreacted low-boiling point raw material that is continuously distilled from the start of the distillation of the distillate containing the dehydrating solvent until the dehydrating solvent is sufficiently distilled off, in order to always effectively exhibit the polymerization inhibiting ability. It can be said that the amount is insufficient. On the other hand, the amount of raw material used is 100
If it exceeds 0 mass ppm, the amount is too large to effectively exhibit the polymerization inhibiting ability, and further effects commensurate with excessive addition cannot be expected, which is uneconomical. The total amount of the antigelling agent used was added at one time, so that the unreacted compounds were successively distilled from the start of the distillation of the distillate containing the dehydrating solvent until the dehydrating solvent was sufficiently distilled off. Since it is difficult to effectively prevent the formation of a gel for low-boiling materials, the distillate containing the dehydrated solvent tends to respond to changes over time in the amount of dehydrated solvent contained in the distillate. It is desirable that the necessary amount be added continuously (continuously) from the start of distillation until the dehydrated solvent is sufficiently distilled off, and the final total amount added should be adjusted within the above range.

The action of the above gelling inhibitor on the distillate (mode of action, region of action, etc.) is based on the unreacted low boiling point raw material (fluid substance) that is successively distilled off. There is no particular limitation as long as it can effectively act (contact), and for example, (a ′) may act on a gaseous distillate before condensed and liquefied, (B ') You may act on the liquid distillate liquefied by coagulation liquefaction. Further, both of the above (a ') and (b') may be utilized.

In the following, the preferable action of the above gelation inhibitor will be described by giving an example for each mode of action, but in the present invention, these can be appropriately combined, and in addition, they are conventionally known. Other methods of action can be used as appropriate. It should be noted that the manners of the operations exemplified below are representative ones by way of example so that those skilled in the art can easily understand the present invention, and the present invention is not limited to these. It goes without saying that there is no such thing.

(1 ') Method of acting the gelation inhibitor in a state of being mixed (dissolved) in a liquid; a suitable liquid (for example,
A solvent, preferably a solvent or water of the same type as the dehydration solvent used in the reaction, mixed with an antigelling agent to form a liquid (may be simply dispersed, but preferably dissolved) Is a region for condensing a distillate containing a dehydrating solvent (preferably an azeotropic distillate of the dehydrating solvent and water), specifically, a condensation liquefaction in which the distillate containing the dehydrating solvent is condensed and liquefied. Equipment, for example, a condenser or the like, preferably from the top of the apparatus such as a condenser (particularly in the vicinity of the top of the column) so that the distillate is dropped or sprayed into the interior thereof in parallel flow contact. Also, depending on the type and type of condensation liquefaction device, a solution containing an anti-gelling agent is charged inside the device such as a condenser, and a gaseous distillate is blown into or liquefied May be poured into and contacted (compatibilized or dispersed). Further, in the above aspect, the action site of the gelation inhibitor is inside the capacitor, but in addition to the above site,
It is provided on the joint (flange) between the reaction tank and the rising line of the vapor, the flange such as the flange between the vapor line and the top of the condenser tower, the thermometer installed in the reaction tank, etc. It may be a portion where gel is easily formed, such as a protruding portion. Among these, the upper part of the condenser (particularly in the vicinity of the top of the tower), the flange between the reaction tank and the rising line of the vapor, and the flange between the vapor line and the top of the condenser are preferred sites for action of the gelation inhibitor. . In addition, the action site is
It does not have to be provided in one place, and a plurality of places may be provided at the same time, if necessary.

(2 ') Method of allowing the gelling inhibitor to act in a solidified state; a region in which the powdered gelling inhibitor is condensed and liquefied from the distillate containing the dehydrating solvent, specifically, the dehydrating solvent is added. A condensate liquefaction device in which condensate liquefaction is carried out, for example inside a condenser, preferably from the top of the device such as a condenser (especially from the top of the column) so that it comes into cocurrent contact with said distillate. It is dropped or scattered to make it fall. Further, depending on the type and type of the device such as the condenser, a gelation preventive agent having a predetermined particle size may be loaded or filled in the inside of the device such as the condenser in advance and brought into contact therewith. Further, in the above aspect as well, the action site of the gelling inhibitor is inside the condenser. However, in addition to the above-mentioned portion, the joint (flange portion) between the reaction tank and the rising line of the vapor and the vapor line and the top of the condenser tower are also provided. It may be a portion where gel is easily formed, such as a flange portion such as a flange portion between and, a thermometer installed in a reaction tank or the like, or a projection portion provided in a viewing window. Among these, the upper part of the condenser (particularly in the vicinity of the top of the tower), the flange between the reaction tank and the rising line of the vapor, and the flange between the vapor line and the top of the condenser are preferred sites for action of the gelation inhibitor. .
Further, the above-mentioned action site does not have to be one, and if necessary, a plurality of sites may be provided at the same time.

(3 ') Method of causing antigelling agent to act in a vaporized state; The antigelling agent is vaporized (including sublimed ones), and distillate containing uncondensed liquefied gas (unreacted A device used to distill the dehydrated solvent before condensing and liquefying (including low-boiling raw materials) (for example, it is desirable to use the reaction device used for the esterification reaction as it is) and a device for condensing liquefaction such as a condenser. It is supplied to and mixed with the inside of a piping path that communicates with.

Among the above (1 ') to (3'), it can be said that the above (1 ') is preferably adopted for the reason described below. That is, it is desirable to distill off and remove the dehydrated solvent at a lower temperature from the economical point of view and handling, and as a method therefor, for example, an appropriate amount of water is used (particularly in the partial neutralization step). When treated with a dilute aqueous alkaline solution, a large amount of water already exists in the system, and this water may be used). When distilling (azeotropic) with a dehydrating solvent using an appropriate amount of water, the low boiling point raw material also moves to the water phase side and is distilled together with water. The proportion of dehydrated solvent in the distillate that is azeotropically distilled with water will decrease, and most of the water (including low-boiling point raw materials) will eventually be distilled off. It is desirable to mix the anti-gelling agent with water by the method (1 ') above so that the solution does not have a sufficient effect, and it is particularly preferable to use a water-soluble anti-gelling agent. It is more desirable that the water-soluble gelling agent is dissolved in water to act. Furthermore, it effectively acts on distillates containing unreacted low-boiling raw materials (that is, when distillates containing low-boiling raw materials are condensed (liquefied), they quickly contact with the liquefaction product). In order to be compatible with or dispersed in a liquefied material (water and an organic solvent) containing a low-boiling raw material which gels, the distillate is subjected to the above method (1 ′). It is desirable to use a gelation inhibitor dissolved in water and / or a solvent depending on the component composition. For example,
Anti-gelling agent composition to act while monitoring changes in composition of distillate over time with a sensor (for example, an anti-gelling agent that dissolves in a solvent, preferably a dehydration solvent, using several types of anti-gelling agents) The composition and the mixing ratio of the anti-gelling agent composition that dissolves in water) may be changed, and the anti-gelling agent that dissolves in a dehydrating solvent may be the one that is dissolved in a dehydrating solvent and the anti-gelling agent that dissolves in water. It is desirable that the substances dissolved in water be made to act by dropping or spraying from different spray nozzles provided in the device such as a condenser through different routes. The reason for adopting the above (1 ′) is that as the amount of the liquid used per unit mass with respect to the antigelling agent increases, the liquid containing the antigelling agent is mixed in the liquefying condensing means 1 (= Heat exchange medium).

Here, as the water-soluble gelling agent that can be used when the gelling agent acts in a state of being dissolved in water, for example, hydroquinone, metoquinone, etc. are preferably used.

On the other hand, when the antigelling agent is allowed to act in a state of being dissolved in a solvent, examples of the solvent capable of dissolving the antigelling agent include benzene, toluene,
Examples thereof include xylene, cyclohexane, acetone, methyl ethyl ketone, n-hexane and heptane, but it is preferable to use the same solvent as the dehydrating solvent used in the esterification reaction. That is, when different solvents are used, to collect and reuse these mixed solvents separately,
It is necessary to perform the separation and purification treatment in multiple stages, the cost required for reuse is high, and the disposable one is lower in cost. However, disposal of the mixed solvent by such disposal (incineration or diluting to below the environmental standard value for wastewater treatment, etc.) also requires a certain cost and causes air pollution or water pollution to some extent. , It goes against what is often said today to create an environment that is kind to the earth. On the other hand, when the same kind of dehydrating solvent is used, it can be said that it can be reused at a low cost by a simple treatment, which is excellent in terms of cost and environment.

In the above preferred embodiment, even when the gelling inhibitor is dissolved in a liquid (water and / or solvent) to act, the generation of a gelled substance can be suppressed so that the gelled substance can be prevented. For the low boiling point raw material (gas or liquefied material) passing through the equipment, the anti-gelling agent should always be present and supplied so as to function effectively. As a mixing ratio of the anti-gelling agent and the liquid Is not particularly limited, but (a) when dissolved in water to act,
To 100 parts by weight of water, a water-soluble gelling agent is added 0.0
In the range of 01 to 10 parts by mass, preferably 0.01 to 5 parts by mass, (a) in the case of being dissolved in a solvent to act, 0.001 to 10 parts of the gelling inhibitor are added to 100 parts by mass of the solvent.
It dissolves in a range of 0.01 part by mass, preferably 0.01 to 5 parts by mass. When the water-soluble anti-gelling agent is less than 0.001 part by mass with respect to 100 parts by mass of water, or the anti-gelling agent is less than 0.001 part by mass with respect to 100 parts by mass of the solvent,
It may be difficult to efficiently and effectively contact the low boiling point raw material in the distillate with an appropriate concentration of the gelling agent. Further, the amount of the liquid per unit mass of the gelling inhibitor increases, and the treatment cost such as disposal after distilling out with the dehydrating solvent out of the system increases, which is economically disadvantageous.
On the other hand, when the water-soluble anti-gelling agent exceeds 10 parts by mass with respect to 100 parts by mass of water, or the anti-gelling agent exceeds 10 parts by mass with respect to 100 parts by mass of the solvent, the amount of the liquid used Since the (total amount added during the removal of the dehydration solvent) is small, the addition amount per unit time and unit volume is limited, the frequency of contact with low boiling point raw materials is relatively reduced, and it remains liquid without contact. It becomes difficult to effectively suppress the formation of gelled material. Therefore, in order to secure the required amount of addition per unit time and unit volume, a large amount of gelation inhibitor more than the amount specified above is required, which increases the manufacturing cost. When using a mixture of water and solvent, use the above (a) depending on the usage ratio.
Without being restricted by the ranges defined in (a) and (a), it may be appropriately adjusted so that the total amount thereof is within the range defined in (a) to (a) above.

In the solvent distillation step, the dehydration solvent is distilled from the solution containing the esterification product and the dehydration solvent in the system, and the dehydration solvent is condensed and liquefied to be removed to the outside of the system. There is no limitation as long as means (apparatus mechanism) for causing the anti-gelling agent to act is provided, and conventionally known apparatus mechanisms can be appropriately combined. For example, in the above-mentioned esterification step, during the esterification reaction, a device mechanism used to circulate the dehydrated solvent in the reaction system by distilling it out from the reaction system, condensing and liquefying it, and returning it to the reaction system (simply called a solvent circulation device). It may be said that this is one of the preferable embodiments since a part of the above may be used and the equipment and the equipment can be simplified and downsized. Specifically, with respect to condensers and the like, which are devices for condensing and liquefying gaseous distillates, the solvent circulation device can be used as it is,
For the water separator, which is a liquid-liquid separator that is a device for separating and removing condensed liquefied distillate, the above-mentioned solvent circulation device can be used by appropriately changing the mode of use. That is, depending on the component composition of the distillate, the liquid distillate transported to the water separator is used to remove water by using a pump or the like which is a transportation route and a transportation device for removing water out of the system. In addition to being able to remove all of the phase part or liquid distillate outside the system, a vacuum pump (ejector) is newly attached to the water separator, etc., and suction is performed, making it a relatively highly volatile component. Etc., or all of the liquid distillate may be removed to the outside of the system. Alternatively, a separate transportation route is provided for the condensed and liquefied distillate from the condenser, etc.
It can also be taken out to a waste treatment device, a recycling treatment device or the like) and appropriately treated (disposed or reused). Further, it is desirable that an appropriate control mechanism is appropriately provided in these devices as well. In addition, as long as it does not deviate from the original purpose of removing the dehydrated solvent in the system by distilling, condensing and liquefying it in place of the apparatus mechanism illustrated above,
It goes without saying that it is possible to appropriately adopt a method by combining other conventionally known means and its device, or a substitute by other means and its device.

In the solvent distillation step, after the esterification reaction is completed (if necessary, the partial neutralization step is carried out), the dehydration solvent is distilled off from the solution containing the esterified product and the dehydration solvent in the system. The method to be carried out is not particularly limited and may be distilled off by azeotropically boiling with a dehydrating solvent using water as described above, or the dehydrating solvent may be effectively added by adding other suitable additives. Alternatively, it can be removed by distillation without using any additive (including water), but it is extremely useful to use an acid catalyst in the esterification reaction (ie, However, its usefulness is extremely high even after considering that it must be partially neutralized after that), a preferred embodiment is a method of distilling and removing by azeotroping with a dehydrating solvent using water. Say one of That. Incidentally, by the solvent distillation step, since a partial neutralization treatment of the acid catalyst has been performed, in the solution containing the esterification product and dehydration solvent in the system,
There is no active acid catalyst and alkali (salts are formed by neutralization), and hydrolysis reaction does not occur even if water is added and the temperature is raised. Therefore, when the dehydrated solvent is distilled off, it is azeotropically distilled with water. I can do things. In addition, azeotropic distillation with water allows the dehydrated solvent to be efficiently removed at a lower temperature.

In the solvent distillation step according to the above preferred embodiment, the dehydration solvent in the system can be suitably distilled (evaporated) as the conditions for distilling the dehydration solvent from the solution in the system. It is not particularly limited as long as it is one, and as the temperature in the system (liquid temperature in the system (under normal pressure)) during solvent distillation, for example, when (1 ″) water is used, it is usually 80 To 120 ° C., preferably 90 to 110 ° C., usually 80 to 16 when (2 ″) water is not used
The temperature is 0 ° C, preferably 90 to 150 ° C. Above (1 ″)
In all cases (2 ″) to (2 ″), if the temperature is lower than the temperature specified above, the temperature (calorific value) is not sufficient to evaporate the dehydration solvent, and it takes a long time to evaporate the dehydration solvent. On the other hand, if the temperature is higher than the temperature specified above, there is a risk of polymerization and a large amount of heat is consumed for the evaporation of a large amount of low boiling point raw material, which is not preferable. The pressure in the system (inside the device) may be either normal pressure or reduced pressure, but it is desirable to perform it under normal pressure from the viewpoint of equipment, and to distill the solvent from the solution containing the dehydrated solvent. It is advisable to use the equipment system (reaction tank) used in the esterification reaction as it is as the equipment system of 1. That is, when the contents are separately transferred to another equipment after the esterification reaction, equipment and management costs are required. Is increased, and Telluride is deteriorated due to external factors (heat, light, transportation temperature, transportation pressure, and the presence of active atmospheric gas), is fixed in the transportation route, and conversely impurities are not eluted from the device during transportation. It is not preferable because it is necessary to prevent the mixture, and extra cost is generated.

In the esterification step, (meth)
In the presence of a polymerization inhibitor to prevent the polymerization of acrylic acid,
When the esterification reaction is performed, the polymerization inhibitor functions effectively even after the esterification reaction (and also after the partial neutralization treatment). , It is not necessary to replenish the polymerization inhibitor newly, but when partial neutralization treatment is performed using a dilute alkaline aqueous solution, a relatively large amount of water is present in the solution in the system. . Therefore, for example, only when the polymerization inhibitor used when carrying out the esterification reaction is sparingly soluble or insoluble in water, (meth) acrylic acid dissolves in water and polymerizes in the solution in the system. Therefore, from the viewpoint of preventing this, it is desirable to raise the temperature to the temperature specified above after adding the water-soluble polymerization inhibitor to the solution in the system.

The water-soluble polymerization inhibitor is not particularly limited, and examples thereof include hydroquinone and
Methoquinone, catechol and their derivatives (eg,
(p-t-butylcatechol etc.), hydroquinone monomethyl ether and the like. Of these, hydroquinone and methoquinone are preferable. These water-soluble polymerization inhibitors may be used alone or in combination of two or more.

The addition amount of the water-soluble polymerization inhibitor is as follows.
0.001 to 1 mass% of the total amount of alcohol and (meth) acrylic acid used as raw materials, preferably 0.1.
It is 001-0.1 mass%. When the addition amount of the water-soluble polymerization inhibitor is less than 0.001% by mass, the expression of the polymerization inhibition ability may be insufficient, and when the addition amount of the water-soluble polymerization inhibitor exceeds 1% by mass. In addition, the polymerization inhibiting ability commensurate with excessive addition is not obtained, which is uneconomical and is not preferable.

Alternatively, after the completion of the esterification reaction (after partial neutralization treatment, if necessary), a water-soluble polymerization inhibitor is added when the dehydrated solvent is distilled off from the reaction solution in the solvent distillation step. It may be added to the reaction solution. However, the present inventors have surprisingly found that by adding a water-soluble polymerization inhibitor that was originally added for the purpose of inhibiting the polymerization, the polymerization inhibitor has a weak polymerization activity, so that it is surprising. , Unreacted raw materials, it was found that the polymerization of the product esterified product or a mixture thereof was caused to form a high molecular weight product, and the polymerization inhibitor added during the esterification reaction was the dehydrated solvent. It has been found that it works effectively even when distilling. Therefore, after the completion of the esterification reaction (after partial neutralization treatment, if necessary), the amount of the water-soluble polymerization inhibitor added when the dehydrated solvent is distilled off from the reaction solution in the solvent distillation step. Is the raw material alcohol and (meta)
It is 1000 mass ppm or less, preferably 500 mass ppm or less, more preferably 300 mass ppm or less based on the total amount of acrylic acid used, and particularly preferably the solvent distillation step is performed without adding a water-soluble polymerization inhibitor. . At this time, the amount of the water-soluble polymerization inhibitor used was 1000 mass ppm with respect to the total amount of the raw material alcohol and (meth) acrylic acid used.
When the amount exceeds the above range, the polymerization activity of the water-soluble polymerization inhibitor causes the generation of the above-mentioned high molecular weight product, and when an esterified product containing these is used as a monomer component, the resulting polymer is It is not preferable because it affects the cement dispersant using the coalescence.

When carrying out the esterification reaction in the presence of the polymerization inhibitor, in the solvent distillation step, the polymerization inhibitor is subjected to the esterification reaction as described above (further, after the partial neutralization treatment). However, it is not necessary to replenish the solution in the system with a new polymerization inhibitor in the solvent distillation step, but using a dilute alkaline aqueous solution to partially If you are doing sum processing,
A relatively large amount of water is present in the reaction solution. for that reason,
For example, only when the polymerization inhibitor used in carrying out the esterification reaction is poorly soluble or insoluble in water and cannot function so effectively after the esterification reaction (and further after the partial neutralization treatment), Since the raw materials for the reaction and the esterified product may be dissolved in water and polymerized, from the viewpoint of preventing this,
Due to the relationship between the polymerization activity due to the polymerization activity of the water-soluble polymerization inhibitor and the intrinsic polymerization inhibition ability, the reaction liquid is allowed to be within the range where the polymerization inhibition ability is more effectively expressed than the polymerization activity (range defined above). It is desirable that the water-soluble polymerization inhibitor be added to the mixture, the temperature be raised to the temperature specified below, and the dehydration solvent be distilled off by azeotropic distillation with water.

Here, the water-soluble polymerization inhibitor that can be used is not particularly limited, and examples thereof include hydroquinone, metoquinone, catechol and their derivatives (for example, pt-butylcatechol).
Hydroquinone monomethyl ether etc. are mentioned. Of these, hydroquinone and metoquinone are preferable because of their relatively low polymerization activity. These water-soluble polymerization inhibitors may be used alone or in combination of two or more.

According to a second concept, the present invention provides the formula (1)
On a reaction vessel for carrying out an esterification reaction of an alcohol with (meth) acrylic acid, a condenser for condensing and liquefying a distillate distilled from the reaction vessel, and a connecting pipe between the reaction vessel and the condenser. An esterification device used in the method for producing an esterified product according to the present invention, comprising a gelation inhibitor supply mechanism provided in at least one part of the above, and a water separator for separating and removing water from the condensate generated from the condenser. Is provided. The apparatus of the present invention is characterized in that it is provided with an antigelling agent supply mechanism that causes an antigelling agent solution containing at least a part of the condensate to act on the distillate. The other device configurations are not particularly limited, and various conventionally known manufacturing devices such as a chemical engineering machine can be appropriately combined and used.

In the anti-gelling agent supply mechanism which can be used in the present invention, the nozzle portion for acting the anti-gelling agent solution is provided in the vicinity of the top of the condenser, that is, inside the top of the condenser or immediately before the condenser. It is desirable that the nozzle portion is provided inside, and more desirably, the nozzle portion is installed upward so that the anti-gelling agent solution can be supplied upward. In particular, the nozzle is located at the top of the condenser or at the center of the distillate path just before the condenser so that the inner wall of the top of the condenser (= distillate inlet) where gel is generated can be constantly wetted. It is desirable to install the nozzle part facing upward. The anti-gelling agent solution is sprayed, blown out, sprayed, ejected, or blown up onto the distillation route from the nozzle provided in the top of the condenser or in the distillation route immediately before the condenser. It can be supplied to the inner wall of the top of the condenser, or supplied to the wall of the overhead line immediately before the condenser, and can be passed along this wall to reach the condenser directly or The inner wall of the condenser can always be wetted indirectly through the inner wall on the path. Therefore, the gelation inhibitor solution can be allowed to act extremely effectively and effectively on the inner wall of the tower top of the condenser where gelled substances are generated.

As one embodiment of the anti-gelling agent supply mechanism, the first anti-gelling agent solution is supplied from the storage section of the anti-gelling agent solution to the nozzle section through the first supply path (appropriate piping and pressure pump). Can be used) and a second supply path (a suitable pipe and a pressure pump can be used) for supplying a part of the condensate to the nozzle portion can be exemplified. Specific embodiments of the gelation inhibitor supply mechanism based on the above concept are illustrated in FIGS. That is, FIG.
Reference numeral 14 denotes a gelation inhibitor supply mechanism, which is a first supply path for supplying the polymerization inhibitor solution from the storage section of the polymerization inhibitor solution to the nozzle section, and a second supply path for supplying a part of the condensate to the nozzle section.
It is a schematic explanatory drawing which shows the aspect of arrangement | positioning relationship with a supply path. More specifically, FIG. 5 shows the first supply path 1a and the second supply path 2 for supplying the condensate by only partially dividing it.
a is arranged so as to supply each to the nozzle section independently; FIG. 6 shows a first supply path 1b and a second supply path 2b for supplying the condensate only in part. 7 are arranged so as to be merged and supplied to the nozzle part; FIG. 7 shows the first supply path 1c and the second supply for supplying a part of the condensed residual liquid from the storage part of the water separator. Route 2c
Are independently arranged to supply to the nozzle part; FIG. 8 shows the first supply path 1d and the second supply for supplying a part of the condensate residual liquid from the storage part of the water separator. Route 2d
Are arranged so as to be merged and supplied to the nozzle part; FIG. 9 shows a first supply path 1e and a second supply path 2e for supplying a part of the residual liquid from the storage tank. It is arranged so as to independently supply the nozzle portion; in FIG. 10, the first supply path 1f and the second supply path 2f for supplying a part of the condensed residual liquid from the storage tank are joined. 11 is arranged so as to supply to the nozzle section; FIG. 11 shows a first supply path 1g, a path 2g ′ for supplying the condensate only in part and a storage part of the water separator. A second supply path 2g consisting of a path 2g ″ for supplying a part of the condensed residual liquid and the second supply path 2g are arranged independently to supply each to the nozzle portion; FIG. 12 shows the first supply path 1h. And a path 2h ′ for supplying the condensate only in part and a water separator The second supply path 2h, which is composed of a path 2h ″ for supplying a part of the condensed residual liquid from the storage section, is arranged so as to be merged and supplied to the nozzle section; FIG. 13 shows the first supply path. 1i and the second supply path 2i for supplying all of the condensate residual liquid from the water separator are independently arranged to supply to the nozzle portion; and FIG. 14 shows the first supply path 1j. And the second supply path 2j for supplying the entire condensed residual liquid from the water separator are arranged so as to be merged and supplied to the nozzle portion.

Further, in the present invention, the second supply path is
Anything may be used as long as it connects the distilling path (particularly the circulation path) for feeding the condensate (particularly the condensate residual liquid) and the nozzle part. For example, directly or by joining the first supply path, It may be, so to speak, indirectly connected to the nozzle portion, and if necessary, a distilling route (especially a circulation route).
A storage unit may be provided above and the storage unit and the nozzle unit may be connected. Examples of the storage unit include, for example, a storage tank provided on the circulation path between the water separator and the reaction tank for temporarily storing the residual condensate and a part of the water separator (see FIG. 2). it can. In addition, it is desirable and appropriate for the first and second supply paths of the anti-gelling agent supply mechanism to be provided with means capable of arbitrarily adjusting the flow rates of a part of the anti-gelling agent solution and the condensate. A flow rate adjusting valve and the like can be exemplified. This allows
It becomes extremely easy to adjust the flow rates of a part of the anti-gelling agent solution and the condensate. Further, when the first supply path and the second supply path are merged, if necessary, a mixing or stirring means for mixing the gelling inhibitor solution and a part of the condensate is provided on one path after the merge. It may be provided, and for example, a baffle plate or a protrusion formed on the inner wall of the path immediately after the confluence portion can be exemplified.
This allows the anti-gelling agent solution and a portion of the condensate to be mixed more quickly and homogeneously. When the first supply path and the second supply path are directly connected to the nozzle part, the anti-gelling agent solution and a part of the condensate are rapidly stirred and mixed in the nozzle part. It is preferable to use a nozzle section having an internal structure that

The apparatus of the present invention is not particularly limited except that the gelation inhibitor supply mechanism is provided, and conventionally known esterification reaction apparatus / mechanism / means, for example, FIG. 1 and the above. A reaction tank for carrying out an esterification reaction of an alcohol with (meth) acrylic acid in the presence or absence of a dehydrating solvent, a polymerization inhibitor and an acid catalyst similar to that described in the explanation of FIG. 1 (related to the reaction tank Raw material storage tank,
(Including various storage tanks such as catalyst storage tank and solvent storage tank, pipes, supply pump, flow rate adjusting valve and switching valve); condenser for condensing and liquefying distillate distilled from the reaction tank; and the condensed and liquefied Reactor such as a distilling path having a water separator for separating and removing reaction product water from the condensate, and a circulation path including a pumping means for refluxing the condensation residual liquid after separation and removal of the reaction product water to the reaction tank -Mechanisms, means, etc. can be appropriately selected and applied.

Next, in the apparatus for producing an esterified product according to the present invention, the anti-gelling agent supply mechanism which is a characteristic feature of the second concept will be described in more detail with reference to FIG. FIG. 2 is a schematic view of a typical device configuration used in the method for producing an esterified product according to the present invention, showing the device configuration including the gelation inhibitor supply mechanism, which is a particularly characteristic part. . Note that other device configurations (for example, storage and supply means for various additives such as raw materials and catalysts) are the same as the device configuration of FIG.

From FIG. 2, as one embodiment of the production apparatus of the present invention including the gelation inhibitor supply mechanism, first, a countercurrent (or cocurrent) flow with the upper part of the reaction tank 501 for carrying out the esterification reaction is carried out.
The tower top of a contact type vertical multi-tube circular condenser 505 is connected by a pipe 503. The reaction tank 501 is provided with a jacket 502 as a heating means (for example, an internal heater, an outer jacket, etc.) and an appropriate stirring device. Further, the lower bottom part of the condenser 505 and the upper part of the water separator 507 are connected by a pipe 520. A partition plate is provided inside the water separator 507, and two chambers partitioned by the partition plate are formed. Of these, the lower part of the chamber on the side where the distillate condensed and liquefied by the condenser 505 is stored and the reaction product water treatment tank (not shown)
Are connected by a pipe (not shown), and a wastewater pipe (not shown) is further connected to the treatment tank. Further, the lower part of the other chamber of the water separator 507 and the upper part of the storage tank 508 for temporarily storing the condensed residual liquid are connected by a pipe 521. The lower part of the storage tank 508 and the upper part of the reaction tank 501 are connected by a pipe 525. Piping 525
A circulation pump 512 is installed on the route. Further, as an anti-gelling agent supply mechanism for these, first, a nozzle portion 506 for spraying an anti-gelling agent solution to the top of the condenser is provided at the center of the top of the condenser 505, The nozzle portion 506 and the anti-gelling agent solution storage tank 509 for storing the anti-gelling agent solution for the purpose of preventing the gelation of the distillate are pipes 523 and 524 (of which gelation is included), which is the first supply path. A portion where only the inhibitor solution is carried is a pipe 523, and a portion where a mixed solution obtained by mixing a part of the condensation residual liquid and the gelation inhibitor is carried is a pipe 524). Next, a pressure pump 510 is installed on the route of the pipe 523. Further, a pipe 522, which is a second supply path for supplying a part of the condensed residual liquid, is connected from the lower portion of the storage tank 508 to the first supply path. A pressure pump 511 is installed on the path of the pipe 522.

In the present invention, the capacitor is S
SU such as US304, SUS316 and SUS316L
Known products such as S and carbon steel (CS) can be used,
Preferably, in order to further reduce the generation of gel, a capacitor whose inner surface is mirror-finished or glass-lined can be used, but in consideration of the cost of processing and maintenance, SUS304, SUS316 and SUS31 are considered.
A SUS capacitor such as 6 L, preferably SUS316 and SUS316L can be preferably used, and even when such a capacitor is used, gel formation can be effectively prevented. The heat transfer area of the condenser preferably used in the present invention varies depending on the volume of the reaction tank and the like, but is, for example, 50 to 500 m ² , preferably 100 to 200 m ² in the reaction tank 30 m ³ . In the present invention,
Examples of the cooling medium used in the condenser include water and oil.

An embodiment relating to the use of the method for producing an esterified product according to the present invention in an apparatus for producing an esterified product having an apparatus configuration including an anti-gelling agent supply mechanism according to the above concept will be described below with reference to FIG. To do.

Alcohol as a raw material and (meth) acrylic acid, an acid catalyst, a polymerization inhibitor and a dehydrating solvent are fed into the reaction tank 501 in the predetermined amounts (prepared), respectively, and the esterification conditions specified above are supplied. The esterification reaction is performed at (reaction temperature, jacket temperature, pressure). The reaction product water sequentially generated by the esterification reaction is the reaction tank 501.
It is azeotropically distilled with the dehydrated solvent charged inside and is distilled out through a pipe 503. The solvent-water azeotrope that is the distilled gas fluid is passed through a condenser 505 to be condensed and liquefied. In order to prevent the low boiling point raw material contained in the azeotrope from gelling during the condensation and liquefaction, an antigelling agent solution is supplied from the storage tank 509 through the pipe 523, and a part of the condensation residual liquid is stored. It is supplied from the tank 508 through a pipe 522, and a gelation inhibitor solution is obtained by merging and mixing these, and supplied through a pipe 524 to a nozzle portion 506 provided at the top of the tower of the condenser 505, from the supply nozzle portion 506. The anti-gelling agent solution in an amount specified above is continuously sprayed or blown upward to wet the entire inner wall including the gas inlet portion at the top of the condenser to distillate (gas fluid and condensed liquefaction). And both of them) are contacted in parallel. The condensed liquefied condensate (including the dropped anti-gelling agent solution) is stored in one chamber of the water separator 507 through the pipe 520 from the lower part of the condenser 505, and is divided into two layers of a water phase and a solvent phase. To be separated. Of these, the lower-layer water phase (including the reaction product water and low-boiling raw materials) is sequentially withdrawn from the lower part of this chamber through a pipe and stored in a treatment tank for the reaction product water. According to the above, after being chemically or biologically processed so as to satisfy the environmental standard (wastewater standard) value, the wastewater is discharged to the outside of the system through a wastewater pipe. On the other hand, the solvent phase of the upper layer (= condensation residual liquid; in addition to the dehydrated solvent, contains the gelation inhibitor solution and the low boiling point raw material)
The partition plate overflows and is stored in the other room next to it. The condensed residual liquid is temporarily stored in the storage tank 508 from the lower part of the other chamber. Of the condensed residual liquid stored in the storage tank 508, the condensed residual liquid in an amount necessary for compensating for the reduced amount of the dehydrated solvent distilled from the reaction tank 501 into the reaction tank 501 through the pipe 525 by the pump 512. Will be returned. Further, a part of the condensed residual liquid stored in the storage tank 508 is sequentially extracted through the pipe 522 by the pump 511 as described above, and is used for forming the gelation inhibitor solution.
As described above, for a while after the start of the reaction, the storage tank 508 does not sufficiently store the condensation residual liquid that can be used for forming the gelation inhibitor solution, and therefore the storage tank 508 stores it sufficiently. Until that time, only the anti-gelling agent solution may be supplied to the nozzle portion 506, or the minimum dehydration solvent necessary for forming the anti-gelling agent solution (or containing an appropriate amount of the anti-gelling agent). Dehydration solvent)
May be charged into the storage tank 508 and supplied from the early stage of the reaction through the pipe 522.

In this way, the esterification reaction was completed (finished when the esterification rate exceeded a specified level).
Then, a neutralizer aqueous solution is added to the reaction tank 501 to neutralize the acid catalyst, and the dehydrated solvent (and excess (meth) acrylic acid) is azeotropically distilled with water under a normal pressure to obtain a desired amount. An esterified product is obtained. In the case of distilling the dehydrated solvent and excess (meth) acrylic acid, the above-mentioned distillate containing the reaction product water produced during the esterification reaction in the reaction tank 501 is distilled to obtain a gel-like substance. After condensing and liquefying while preventing the occurrence of
The reaction product water can be separated and removed, and a part of the apparatus configuration for refluxing the remaining distillate can be used. In this case, since it is necessary to remove the dehydrated solvent and the excess (meth) acrylic acid to the outside of the system without refluxing,
Vacuum pump (ejector) attached to the water separator 507
Is taken out of the system using. In addition, these may be discarded or may be chemically treated and reused using an apparatus outside the system. On the other hand, the obtained esterified product is recovered from the reaction tank 501 to the esterified product storage tank through a pipe. When used for the synthesis of a cement dispersant or the like, as described in detail below, the obtained esterified product is further polymerized in the reaction tank 501 as one of the monomer components to obtain the cement dispersant. You may make it synthesize | combine the polymer which can become a main composition component.

Although one embodiment of the esterification product producing apparatus of the present invention has been described above with reference to FIG. 3, the esterification product producing apparatus of the present invention is not limited to the embodiment. The reaction product water generated during the esterification reaction can be distilled from the reaction tank to a distilling route or a circulation route, and the anti-gelling agent solution can effectively act on the distillate containing the reaction product water. If so, the manufacturing method (means), device configuration, etc. are not limited at all, and conventionally known manufacturing methods, device configurations, etc. can be appropriately combined and used.

According to the third concept, while the anti-gelling agent solution containing at least a part of the condensate is allowed to act on the distillate, the following formula:

[0167]

[Chemical 14]

(Wherein R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms, R ² O represents an oxyalkylene group having 2 to 18 carbon atoms, and the repeating unit of each R ² O is They may be the same or different, and when R ² O is in the form of a mixture of two or more species, the repeating units of each R ² O may be added in blocks or randomly. And n represents the average number of moles of addition of the oxyalkylene group,
Alkoxypolyalkylene glycol mono (meth) acrylic acid-based monomer (a) is obtained by an esterification reaction of an alkoxypolyalkyleneglycol represented by the formula (00) and (meth) acrylic acid. Alkylene glycol mono (meth) acrylic acid-based monomer (a) 5 to 98% by mass, the following formula (2):

[0169]

[Chemical 15]

(Wherein R ³ represents hydrogen or a methyl group, and M ¹ represents hydrogen, a monovalent metal, a divalent metal, an ammonium group or an organic amine group) (meta).
Acrylic acid-based monomer (b) 95 to 2 mass% and other monomer (c) 0 to 50 mass% copolymerizable with these monomers (provided that (a), (b) and The total of (c) is 10
0% by mass) for producing a polycarboxylic acid-based copolymer for cement dispersant (herein referred to simply as "copolymer" or "polymer"). To do.

In the above concept, n represents the average number of moles of the oxyalkylene group added, and it is an essential requirement that it be a number of 1 to 300. In the present specification, n in the above formula (1) is used. The alcohol of the formula (1) in which is 1 to 300 is referred to as "alkoxy polyalkylene glycol", and the alkoxy polyalkylene glycol and (meth)
The compound obtained by the esterification reaction with acrylic acid is referred to as "alkoxy polyalkylene glycol mono (meth) acrylic acid-based monomer".

In the above concept, the alkoxypolyalkylene glycol is defined in the same manner as the alcohol in the first concept except that n does not contain 0. Also,
The terms used in the above first and second concepts have the same meaning, such as (meth) acrylic acid and esterification reaction.

In the esterification reaction according to the third concept, the amount of alkoxypolyalkylene glycol and (meth) acrylic acid used is such that the amount of alkoxypolyalkylene glycol used is p parts by mass and the amount of (meth) acrylic acid used. Is q mass parts, it is preferable that the amount satisfies the following formula: 40 ≦ [(p / n ^1/2 ) / q] × 100 ≦ 200. As a result, when (meth) acrylic acid is allowed to exist in excess relative to the alkoxypolyalkylene glycol and the esterification reaction is carried out, the resulting alkoxypolyalkyleneglycol mono (meth) acrylic acid-based monomer becomes (meth) acrylic Since it exists in the form of a mixture containing an acid, the mixture may be used as it is without isolation, or if necessary, a (meth) acrylic acid (salt) monomer or a monomer copolymerizable with these monomers may be added. It is preferable that the mixture is subjected to a copolymerization reaction as it is without isolation so that a polycarboxylic acid type copolymer can be produced. That is, the step of isolating the alkoxypolyalkylene glycol mono (meth) acrylic acid can be omitted by adjusting the amounts of the alkoxypolyalkylene glycol and (meth) acrylic acid used within the ranges described above. Therefore, it is suitable for mass production and is preferable from an industrial viewpoint.

In the above preferred embodiment, p parts by mass which is the amount of alkoxypolyalkylene glycol used and q parts by mass which is the amount of (meth) acrylic acid used are represented by the following formula: 40 ≦ [(p / n ^1/2 ). / Q] × 100 ≦ 200 (where n represents the average number of moles of the oxyalkylene group added, and is a number of 1 to 300). As used herein, the formula: [(p / n
The value of ^1/2 ) / q] × 100 is also referred to as “K value”, and the K value is a scale representing the average number of polyalkylene glycol chains per mass of carboxylic acid. In the present invention, K
The value is preferably 42 to 190 (42 ≦ K value ≦ 19
0), more preferably 45 to 160 (45 ≦ K value ≦ 16
In this case, when the K value is less than 40, the cement dispersant obtained has insufficient cement dispersion performance. On the other hand, when the K value exceeds 200, the cement dispersant performance of the obtained cement dispersant also deteriorates, the esterification reaction time remarkably increases, and the productivity significantly decreases, which is not preferable.

The method for producing a polycarboxylic acid type copolymer (including a salt thereof; the same applies hereinafter) in the third concept is as follows.
As long as the polymer of the present invention can be obtained by carrying out a polymerization reaction with an alkoxypolyalkylene glycol mono (meth) acrylic acid monomer as a monomer component, depending on the intended use. It should be understood that it is not particularly limited and includes those obtained by polymerization depending on the intended use. For example, Japanese Patent Publication Sho 59-1833
No. 8, JP-A-9-86990 and JP-A 9-2.
In the same manner as a known method such as the method described in Japanese Patent Publication No. 86645, (meth) acrylic acid (salt) and, if necessary, subjected to a polymerization reaction together with a monomer copolymerizable with these monomers. According to the present invention, it is possible to obtain a cement dispersant having excellent cement dispersibility, but it is not limited thereto, and the polymerization method described in each publication exemplified in the detailed description of the polymer of the present invention can be applied. Needless to say, other various known polymerization methods can be applied in addition to these. In addition to the above methods, it can be used as a pigment dispersant for calcium carbonate, carbon black, ink, scale inhibitor, gypsum / water slurry dispersant, CWM dispersant, thickener, and the like.

More specifically, for example, in the method for producing a polycarboxylic acid type copolymer of the present invention, an alkoxypolyalkylene glycol mono (meth) acrylic acid type monomer is added to (meth) acrylic acid (salt). A polymerization reaction is carried out with the monomers and, if necessary, the monomers copolymerizable with these monomers.

Here, in order to obtain a desired polycarboxylic acid type copolymer, an alkoxypolyalkylene glycol mono (meth) acrylic acid type monomer component or the like may be copolymerized using a polymerization initiator. The copolymerization can be carried out by a method such as polymerization in a solvent or bulk polymerization.

Polymerization in a solvent can be carried out batchwise or continuously, and the solvent used at that time is as follows.
Water; lower alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane, n-hexane; ester compounds such as ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone And the like. From the solubility of the monomer component of the esterified material as the raw material and the solubility of the resulting copolymer and the convenience of using the copolymer, at least one selected from the group consisting of water and a lower alcohol having 1 to 4 carbon atoms is selected. It is preferable to use one kind. In that case, among lower alcohols having 1 to 4 carbon atoms, methyl alcohol, ethyl alcohol, isopropyl alcohol and the like are particularly effective.

When carrying out the polymerization in an aqueous medium, a water-soluble polymerization initiator such as ammonium or alkali metal persulfate or hydrogen peroxide is used as the polymerization initiator.
At this time, an accelerator such as sodium bisulfite and Mohr's salt may be used in combination. For polymerization using a lower alcohol, aromatic hydrocarbon, aliphatic hydrocarbon, ester compound or ketone compound as a solvent, peroxides such as benzoyl peroxide and lauroyl peroxide; hydroperoxides such as cumene hydroperoxide; azo An aromatic azo compound such as bisisobutyronitrile is used as a polymerization initiator. At this time, an accelerator such as an amine compound may be used in combination. Further, when a water-lower alcohol mixed solvent is used, it can be appropriately selected and used from the above various polymerization initiators or a combination of a polymerization initiator and an accelerator. The polymerization temperature is appropriately determined depending on the solvent and the polymerization initiator used, but is usually 0 to 1
It is carried out within the range of 20 ° C.

Bulk polymerization is carried out using a peroxide such as benzoyl peroxide or lauroyl peroxide; a hydroperoxide such as cumene hydroperoxide; an aliphatic azo compound such as azobisisobutyronitrile or the like as a polymerization initiator, It is carried out within a temperature range of 200 ° C.

A thiol chain transfer agent may be used in combination for controlling the molecular weight of the obtained polymer. The thiol chain transfer agent used in this case has the formula: HS-
R ⁵ —E _g (wherein R ⁵ represents an alkyl group having 1 to 2 carbon atoms, E represents —OH, —COOM ² , —COO)
R ⁶ or —SO ₃ M ² group, M ² represents hydrogen, monovalent metal, divalent metal, ammonium group or organic amine group, R ⁶ represents an alkyl group having 1 to 10 carbon atoms, and g Represents an integer of 1 to 2. ), For example, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, octyl 3-mercaptopropionic acid, and the like. 1 type (s) or 2 or more types can be used.

The polymer thus obtained may be used as it is as a main component for various purposes such as a cement dispersant. If necessary, a polymer salt obtained by further neutralizing with an alkaline substance may be added. You may use it as a main component for various uses, such as a cement dispersant. Preferred examples of such alkaline substances include inorganic substances such as hydroxides, chlorides and carbon salts of monovalent and divalent metals; ammonia; organic amines and the like.

In the method for producing a polymer of the present invention, the alkoxypolyalkylene glycol mono (meth) acrylic acid type monomer components that can be used may be used alone or in combination of two or more. You may use it. In particular, when two or more kinds are used as a mixture, it is desirable to use a combination of different types having different expression characteristics so that the characteristics (function, performance, etc.) according to the intended use can be expressed. The following two combinations are advantageous.

That is, in the alkoxypolyalkylene glycol mono (meth) acrylic acid type monomer, the first esterified product in which the average number of added moles n in the formula (1) is 1 to 97, preferably an integer of 1 to 10 (A ¹ )
And the average added mole number n in the formula (1) is 4 to 100,
A mixture with the ^second esterified product (a ² ) which is preferably an integer of 11 to 100 (wherein the average added mole number of the second esterified product (a ² ) is the first esterified product (a ¹ ). Is larger than the average number of added moles by 3 or more).

The method for producing such a mixture of the first esterified product (a ¹ ) and the second esterified product (a ² ) is as described in the method for producing the esterified product. The first and second esterification products (a ¹ ) and (a ² ) may be separately produced by an esterification reaction, or may be produced by an esterification reaction of a mixture of corresponding alcohols and (meth) acrylic acid. In particular, the latter method can provide an industrially inexpensive manufacturing method.

In this case, the mass ratio of the first esterified product (a ¹ ) to the second esterified product (a ² ) is 5: 95-9.
It is 5: 5, preferably 10:90 to 90:10.

Examples of the ^first esterified product (a ¹ ) include methoxy (poly) ethylene glycol mono (meth) acrylate, methoxy (poly) propylene glycol mono (meth) acrylate, methoxy (poly) butylene glycol mono (meth). ) Acrylate, methoxy (poly) ethylene glycol (poly) propylene glycol mono (meth) acrylate, methoxy (poly) ethylene glycol (poly) butylene glycol mono (meth) acrylate, methoxy (poly) propylene glycol (poly) butylene glycol mono ( (Meth) acrylate, methoxy (poly) ethylene glycol (poly) propylene glycol (poly) butylene glycol mono (meth) acrylate, ethoxy (poly) ethylene glycol mono (meth) acrylate , Ethoxy (poly) propylene glycol mono (meth) acrylate, ethoxy (poly) butylene glycol mono (meth) acrylate, ethoxy (poly) ethylene glycol (poly) propylene glycol mono (meth) acrylate, ethoxy (poly) ethylene glycol (Poly) butylene glycol mono (meth) acrylate, ethoxy (poly) propylene glycol (poly) butylene glycol mono (meth) acrylate, ethoxy (poly) ethylene glycol (poly) propylene glycol (poly) butylene glycol mono (meth) acrylate, etc. Is exemplified. First
It is important that the esterified product (a ¹ ) of ( ¹ ) has hydrophobicity in the short chain alcohol of its side chain.

From the viewpoint of easy copolymerization, it is preferable that the side chain contains a large amount of ethylene glycol units. Therefore, as (a ¹ ), (alkoxy) (poly) ethylene glycol mono (meth) acrylate having an average number of added moles of 1 to 97, preferably 1 to 10, is preferable.

Examples of the ^second ester compound (a ² ) include methoxypolyethylene glycol mono (meth) acrylate and methoxypolyethylene glycol (poly).
Propylene glycol mono (meth) acrylate, methoxy polyethylene glycol (poly) butylene glycol mono (meth) acrylate, methoxy polyethylene glycol (poly) propylene glycol (poly) butylene glycol mono (meth) acrylate, ethoxy polyethylene glycol mono (meth) acrylate, Ethoxy polyethylene glycol (poly) propylene glycol mono (meth) acrylate, ethoxy polyethylene glycol (poly) butylene glycol mono (meth) acrylate, ethoxy polyethylene glycol (poly) propylene glycol (poly) butylene glycol mono (meth) acrylate, etc. are exemplified. It

In order to obtain a high water-reducing property, it is important to disperse the cement particles with steric repulsion and hydrophilicity due to an alcohol chain having an average addition mole number of the second esterified product (a ² ) of 4 to 100. . For that purpose, it is preferable that many oxyethylene groups are introduced into the polyalkylene glycol chain, and the polyethylene glycol chain is most preferable. Therefore, the average addition mole number n of the alkylene glycol chain of the second esterified product (a ² ) is 4 to 100, preferably 11 to 100.

Examples of the above-mentioned (meth) acrylic acid (salt) monomers that can be used in the method for producing a polymer of the present invention include acrylic acid, methacrylic acid and monovalent metal salts of these acids. , Divalent metal salts, ammonium salts, and organic amine salts, and one or more of these can be used.

Examples of monomers copolymerizable with the monomer components of the esterified monomer and the (meth) acrylic acid (salt) monomer that can be used in the method for producing a polymer of the present invention Are dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid and itaconic acid; these dicarboxylic acids and HO (R ¹¹ O) _r R ¹² (provided that
R ¹¹ O represents one kind or a mixture of two or more kinds of oxyalkylene groups having 2 to 4 carbon atoms, and in the case of two kinds or more, they may be added in a block form or in a random form, r represents the average number of moles of the oxyalkylene group added and represents an integer of 1 to 100, and R ¹² represents hydrogen or an alkyl group having 1 to 22 carbon atoms, preferably 1 to 15 carbon atoms. ) Monoesters or diesters with alcohols; unsaturated amides such as (meth) acrylamide and (meth) acrylalkylamide; vinyl esters such as vinyl acetate and vinyl propionate; vinyl sulfonic acid, (meth) Unsaturated sulfonic acids such as allyl sulfonic acid, sulfoethyl (meth) acrylate, 2-methylpropane sulfonic acid (meth) acrylamide, and styrene sulfonic acid, and their monovalent metal salts, divalent metal salts, aluminum salts, organic amine salts; Styrene, α-
Aromatic vinyls such as methylstyrene; C1-C1
8, preferably 1 to 15 esters of phenyl group-containing alcohol such as aliphatic alcohol or benzyl alcohol with (meth) acrylic acid; polyalkylene glycol mono (meth) acrylate; polyalkylene glycol mono (meth) allyl ether, etc. And one or more of these can be used.

The cement dispersant of the present invention containing the copolymer thus obtained as a main component can exhibit good cement dispersibility and slump retention performance.

The cement dispersant of the present invention includes, in addition to the polymer component defined above, a conventionally known naphthalene-based cement dispersant, aminosulfonic acid-based cement dispersant,
You may mix | blend at least 1 sort (s) of cement dispersant selected from the group which consists of a polycarboxylic acid type cement dispersant and a lignin type cement dispersant. That is, in the cement dispersant of the present invention, the polymer may be used alone, or if necessary, various components shown above and below may be blended in order to further add value. However, the blending composition of these is largely different depending on the presence or absence of the intended additional function, and the above-mentioned polymer component is highly added from 100% by mass (total amount) to the main component. As a value component, there are various modes including an appropriate amount added to a conventional cement dispersant, and it cannot be uniquely defined. However, the blending amount of the polycarboxylic acid-based copolymer in the cement dispersant of the present invention is usually 5 to 100% by mass based on all components,
It is preferably 50 to 100% by mass.

The cement dispersant of the present invention includes, in addition to the conventionally known cement dispersants, an air entraining agent, a cement wetting agent, a swelling agent, a waterproofing agent, a retarding agent, a quick-setting agent, and a water-soluble polymer substance. , Thickener, flocculant, dry shrinkage reducer, strength enhancer,
A curing accelerator, a defoaming agent, etc. can be added.

The cement dispersant containing the polymer thus obtained as a main component promotes the dispersion of the cement by blending it with the cement composition comprising at least cement and water.

The cement dispersant of the present invention can be used in hydraulic cements such as Portland cement, belite-rich cement, alumina cement, various mixed cements, and hydraulic materials other than cements such as gypsum.

Since the cement dispersant of the present invention exhibits the above-mentioned effects, even when added in a small amount, it exhibits an excellent effect as compared with the conventional cement dispersants. For example, when used in mortar or concrete using hydraulic cement, an amount of 0.001 to 5%, preferably 0.01 to 1% of the cement mass may be added during kneading. . By this addition, various desirable effects such as achievement of high water reduction rate, improvement of slump loss prevention performance, reduction of unit water amount, increase of strength, improvement of durability are brought about. If the added amount is less than 0.001%, the performance is insufficient, and conversely, even if a large amount of more than 5% is used, the effect is substantially capped and it is disadvantageous from the economical aspect.

The cement dispersant of the present invention is a cement dispersant mainly composed of a polymer having a specific weight average molecular weight and having a specific value obtained by subtracting the peak top molecular weight from the weight average molecular weight. Is desirable. At this time, the weight average molecular weight of the polycarboxylic acid-based copolymer according to the present invention is appropriately determined in the optimum range according to the intended use, for example, in terms of polyethylene glycol by gel permeation chromatography. Fifty
The range of 0-500000, especially 5000-300000 is preferable. The value obtained by subtracting the peak top molecular weight from the weight average molecular weight of the polymer is 0 to 800.
It is necessary to be 0, and preferably 0 to 7000. When the weight average molecular weight is less than 500, the water-reducing performance of the cement dispersant deteriorates, which is not preferable. Meanwhile, 5
If the molecular weight exceeds 00000, the water-reducing performance of the cement dispersant and the ability to prevent slump loss decrease, which is not preferable. Further, if the value obtained by subtracting the peak top molecular weight from the weight average molecular weight exceeds 8000, the slump retention performance of the obtained cement dispersant is deteriorated, which is not preferable.

[0200]

EXAMPLES The present invention will be described more specifically below with reference to examples. In the examples, unless otherwise specified,
"%" Means "mass%", and "part" means "part by mass".

Example 1 Thermometer, stirrer, produced water separator and multi-tube condenser [body (shell): inner diameter 750 mm × length 4000 m]
m, heat transfer tube (tube): inner diameter 24 mm x 485, heat transfer area: 150 m ² ] in a glass-lined reaction tank (internal volume: 30 m ³ ) with an outer jacket, methoxypoly (n = 25) ethylene glycol 16500 parts Then, 4740 parts of methacrylic acid (K value = 70), 235 parts of paratoluenesulfonic acid monohydrate, 5 parts of phenothiazine and 1060 parts of cyclohexane were charged, and an esterification reaction was carried out at a reaction temperature of 115 ° C. Separately, from the start of the reflux of cyclohexane to the end of the esterification reaction, a cyclohexane solution (A) containing phenothiazine (the concentration of phenothiazine in cyclohexane was set to 1000 mass ppm) was added at a rate of 0.35 parts / min to a water separator. Part of the residual liquid (mainly cyclohexane) circulated from the reactor to the reaction tank (B)
At a speed of 20 parts / min, after mixing (A) and (B),
It descended to the top of the condenser through an upward nozzle provided in the condenser.

It was confirmed that the esterification rate reached 100% in about 20 hours. Then, 135 parts of a 49% sodium hydroxide aqueous solution and 4890 parts of water were added to neutralize paratoluenesulfonic acid, 8 parts of hydroquinone was added and the temperature was raised, and cyclohexane was distilled off azeotropically with water. During the distillation of cyclohexane, 301 parts of water containing 1 part of hydroquinone was added dropwise to the top of the condenser. After distilling off cyclohexane, adjusted water was added to obtain 80% aqueous esterification solution (1).
After repeating the above operation for 3 batches, the inside of the capacitor was visually inspected and no gel-like matter was found. When the above batch operation was continued for another year and then the inside of the capacitor was visually inspected, only a very small amount of gel-like material was confirmed. This was extremely small when compared with the following Example 4 in one year, and was visually reduced to 1/10 or less than that of Example 4.

Tables 1 to 3 below show the reaction composition, the reaction conditions, the composition of the gelling agent solution that descends to the top of the condenser, the partial neutralization conditions, the solvent distillation conditions and the experiment results of this example.

Example 2 In Example 1, the thermometer, the stirrer, the produced water separator and the multi-tube condenser [body (shell): inner diameter 750 mm]
× Length 4000 mm, heat transfer tube (tube): inner diameter 24 m
m × 485 tubes, heat transfer area: 150 m ² ], with external jacket, made of SUS316 reaction tank (internal volume: 30 m ³ )
When the inside of the capacitor was visually inspected in the same manner as in Example 1 except that was used as a reaction tank, no gel was found. When the above batch operation was continued for another year and then the inside of the capacitor was visually inspected, only a very small amount of gel-like material was confirmed.

Example 3 In Example 1, a glass reaction vessel with an outer jacket (internal volume: 30 liters) equipped with a thermometer, a stirrer, a produced water separator and a reflux condenser (condenser) is used as the reaction vessel. When the inside of the capacitor was visually inspected in the same manner as in Example 1 except for the above, no gel-like substance was generated.
After the batch operation was continued for another year, the inside of the reflux condenser, which was a condenser, was visually inspected, and only a very small amount of gel-like material was confirmed.

Example 4 Thermometer, stirrer, produced water separator and multi-tube condenser [body (shell): inner diameter 750 mm × length 4000 m]
m, heat transfer tube (tube): inner diameter 24 mm x 485, heat transfer area: 150 m ² ] in a glass-lined reaction tank (internal volume: 30 m ³ ) with an outer jacket, methoxypoly (n = 25) ethylene glycol 16500 parts , Methacrylic acid 4740 parts, paratoluenesulfonic acid monohydrate 235 parts, phenothiazine 5 parts and cyclohexane 1
After charging 060 parts, an esterification reaction was carried out at a reaction temperature of 115 ° C. Separately, from the start of the reflux of cyclohexane to the end of the esterification reaction, 0.35 parts / mi of the cyclohexane solution (A) containing phenothiazine (the concentration of phenothiazine in cyclohexane was set to 1000 mass ppm).
20 parts / min of a part (B) of the residual liquid (mainly cyclohexane) circulated from the water separator to the reaction tank at a speed of n.
After mixing (A) and (B) at a speed of 1, the mixture was dropped to the top of the condenser through a downward nozzle provided in the condenser.

It was confirmed that the esterification rate reached 100% in about 20 hours. Then, 135 parts of a 49% sodium hydroxide aqueous solution and 4890 parts of water were added to neutralize paratoluenesulfonic acid, 8 parts of hydroquinone was added and the temperature was raised, and cyclohexane was distilled off azeotropically with water. During the distillation of cyclohexane, 301 parts of water containing 1 part of hydroquinone was added dropwise to the top of the condenser. After distilling off cyclohexane, adjusted water was added to obtain an 80% aqueous esterification solution. When the above operation was repeated 3 batches and then the inside of the capacitor was inspected, no gel-like substance was generated. When the above batch operation was continued for another year and then the inside of the capacitor was visually inspected, it was confirmed that a very small amount of gel-like matter had been generated. This was visually observed to have a difference of 10 times or more when compared with that of Example 1 for one year.

Tables 1 to 3 below show the reaction composition, the reaction conditions, the composition of the gelling agent solution that descends to the top of the condenser, the partial neutralization conditions, the solvent distillation conditions and the experiment results of this example.

Example 5 In Example 4, a thermometer, a stirrer, a produced water separator and a multi-tube condenser [body (shell): inner diameter 750 mm]
× Length 4000 mm, heat transfer tube (tube): inner diameter 24 m
m × 485 tubes, heat transfer area: 150 m ² ], with external jacket, made of SUS316 reaction tank (internal volume: 30 m ³ )
When the inside of the capacitor was visually inspected in the same manner as in Example 4 except that was used as a reaction tank, no gel-like substance was generated. When the above batch operation was continued for another year and then the inside of the capacitor was visually inspected, it was confirmed that a very small amount of gel-like matter had been generated.

Example 6 In Example 4, a glass reactor equipped with an outer jacket (internal volume: 30 liters) equipped with a thermometer, a stirrer, a produced water separator and a reflux condenser (condenser) is used as the reactor. Other than the above, the inside of the capacitor was visually inspected in the same manner as in Example 4, and no gel-like substance was generated.
After the batch operation was continued for another year, the inside of the reflux condenser, which was a condenser, was visually inspected, and it was confirmed that a very small amount of gel-like matter was generated.

Comparative Example 1 Thermometer, stirrer, water separator and multi-tube condenser [body (shell): inner diameter 750 mm x length 4000 mm, heat transfer tube (tube): inner diameter 24 mm x 485, heat transfer area: 150 m] ² ] in a glass lining reaction vessel with an outer jacket (content volume: 30 m ³ ) in an amount of 16500 parts of methoxypoly (n = 25) ethylene glycol, 4740 parts of methacrylic acid, and paratoluenesulfonic acid monohydrate 2
35 parts, phenothiazine 5 parts and cyclohexane 10
60 parts were charged and the esterification reaction was carried out at a reaction temperature of 115 ° C. Separately, from the start of the reflux of cyclohexane to the end of the esterification reaction, only the cyclohexane solution (A) containing phenothiazine (the concentration of phenothiazine in cyclohexane was 1000 mass ppm) was 0.35 part / m 2.
At a rate of in, it was lowered to the top of the condenser through a downward nozzle provided in the condenser.

It was confirmed that the esterification rate reached 100% in about 20 hours. Then, 135 parts of a 49% sodium hydroxide aqueous solution and 4890 parts of water were added to neutralize paratoluenesulfonic acid, 8 parts of hydroquinone was added and the temperature was raised, and cyclohexane was distilled off azeotropically with water. During the distillation of cyclohexane, 301 parts of water containing 1 part of hydroquinone was added dropwise to the top of the condenser. After distilling off cyclohexane, adjusted water was added to obtain an 80% aqueous esterification solution. When the above operation was repeated 3 batches and then the inside of the capacitor was inspected, no gel-like substance was generated. When the inside of the capacitor was visually inspected after the above batch operation was continued for another year, it was confirmed that a gel-like material was generated. This was visually observed to be 1000 times or more different from that of Example 1 for one year.

Tables 1 to 3 below show the reaction composition, the reaction conditions, the composition of the solution of the polymerization inhibitor that descends to the top of the condenser, the partial neutralization conditions, the conditions for distilling the solvent, and the experimental results of this example.

Comparative Example 2 A glass reaction vessel (internal volume: 30 liters) equipped with an external jacket equipped with a thermometer, a stirrer, a produced water separator and a reflux condenser (condenser) was charged with methoxypoly (n = 25) ethylene glycol 16500. Part, methacrylic acid 4740
Parts, 235 parts of paratoluenesulfonic acid monohydrate, 5 parts of phenothiazine and 1060 parts of cyclohexane were charged, and an esterification reaction was carried out at a reaction temperature of 115 ° C. From the start of the reflux of cyclohexane to the end of the esterification reaction, no gelation prevention measures were taken, and therefore, neither the condensation residual liquid nor the gelation inhibitor solution was allowed to act.

It was confirmed that the esterification rate reached 100% in about 20 hours. Then, 135 parts of a 49% sodium hydroxide aqueous solution and 4890 parts of water were added to neutralize paratoluenesulfonic acid, 8 parts of hydroquinone was added and the temperature was raised, and cyclohexane was distilled off azeotropically with water. During the distillation of cyclohexane, 301 parts of water containing 1 part of hydroquinone was added dropwise to the top of the condenser. After distilling off cyclohexane, adjusted water was added to obtain an 80% aqueous esterification solution. When the inside of the capacitor was inspected after repeating the above operation for 3 batches, generation of a large amount of gel-like substance was recognized.

The reaction compositions, reaction conditions, partial neutralization conditions, solvent distillation conditions and experimental results of this comparative example are shown in Tables 1 to 3 below.

In Comparative Example 2 in which the gel-like material was easy to observe, when the inside of the condenser, which was the condenser, was observed periodically, the gel-like material was often found at the top of the condenser. Further, a part of the gel-like material generated here runs down, so that the gel-like material can be confirmed in the entire capacitor.

[0218]

[Table 1]

[0219]

[Table 2]

[0220]

[Table 3]

Example 7 Next, a glass reaction vessel with an outer jacket (internal volume) equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introducing tube, a thermometer, a stirrer, a produced water separator and a reflux condenser (condenser) : 30 liter) was charged with 8200 parts of water, the reactor was replaced with nitrogen under stirring, and the temperature was raised to 80 ° C. under a nitrogen atmosphere. Next, 3100 parts of 13100 parts of the 80% aqueous esterification product solution (1) obtained in Example 1 was added to the reactor.
A solution in which 94 parts of mercaptopropionic acid was dissolved was added dropwise over 4 hours, and at the same time, ammonium persulfate 125
An aqueous solution in which 1000 parts of water was dissolved was added dropwise over 5 hours. After the dropping was completed, the reaction mixture was maintained at 80 ° C. for 1 hour. Furthermore, the pH of this reaction mixture was adjusted to 8 with sodium hydroxide to obtain the polycarboxylic acid (1) of the present invention having a weight average molecular weight of 21,000 in terms of polyethylene glycol by gel permeation chromatography. .

The polycarboxylic acid (1) thus obtained was used as it was as a cement dispersant.
Cement composition (1) was prepared according to the mortar test method, and the flow value was measured. The results are shown in Table 4 below.

<Mortar test method> Water 240 containing the cement dispersant [polycarboxylic acid (1)] obtained above.
Parts, 400 parts of ordinary Portland cement (manufactured by Taiheiyo Cement) as cement, and 800 parts of Toyoura standard sand were kneaded with a mortar mixer to prepare a cement composition (1). The amount of cement dispersant added is shown in Table 4 below.

Next, this cement composition (1) was treated with a diameter of 5
After filling a hollow cylinder with a height of 5 mm and a height of 55 mm, the cylinder was gently lifted vertically to spread the cement composition (1).
The major axis and the minor axis were measured and the average value was used as the flow value.

Example 8 Example 8 was repeated except that the amount of methoxypoly (n = 25) ethylene glycol was changed to 19430 parts and the amount of methacrylic acid was changed to 1810 parts (K value = 215). When the same esterification reaction as in 1 was performed, an esterification rate of about 99% was confirmed in about 90 hours. Next, after cyclohexane was distilled off azeotropically with water, adjusted water was added to obtain 80% aqueous esterification product solution (2).

Next, water 820 was placed in a glass reaction vessel (internal volume: 30 liters) with an external jacket equipped with a thermometer, a stirrer, a produced water separator and a reflux condenser (condenser).
0 part was charged, the reactor was replaced with nitrogen under stirring, and the temperature was raised to 80 ° C. under a nitrogen atmosphere. Subsequently, the 80% aqueous solution of the esterified product (2) obtained above was placed in the reactor.
A solution prepared by dissolving 58 parts of 3-mercaptopropionic acid in 13700 parts was dropped over 4 hours, and at the same time, an aqueous solution prepared by dissolving 122 parts of ammonium persulfate in 2300 parts of water was dropped over 5 hours. After the dropping was completed, the reaction mixture was maintained at 80 ° C. for 1 hour. Furthermore, p of this reaction mixture
By adjusting H so as to be 8 with sodium hydroxide, the weight average molecular weight in terms of polyethylene glycol by gel permeation chromatography was 1970.
0 polycarboxylic acid (2) was obtained.

Using the polycarboxylic acid (2) thus obtained as it is as a cement dispersant, Example 7
The cement composition (2) was prepared in the same manner as in 1. and the flow value was measured. The results are shown in Table 4 below.

[0228]

[Table 4]

From the results shown in Table 4, it was confirmed that when the K value exceeds the upper limit of the preferable range (40 to 200), the flow value remarkably decreases and therefore the cement dispersibility decreases.

[0230]

INDUSTRIAL APPLICABILITY The method for producing an esterified product according to the present invention is a method for producing an esterified product by an esterification reaction of an alcohol represented by the formula: R ¹ O (R ² O) _n H and (meth) acrylic acid. In the above, a gelling material is generated by attaching a liquefied distillate to the distillate by causing a gelling agent solution containing at least a part of the condensate to act on the distillate. Since it is possible to supply a sufficient amount of a solution containing an antigelling agent to the inner wall surface of a condenser or a condenser and keep it in a wet state at all times, it is possible to always effectively generate a gelled substance on the distilling route. Therefore, high-quality esluride can be produced efficiently and at low cost, and the performance and quality of products such as cement dispersants produced using the esterification product are not deteriorated.

Further, a part of the condensate residual liquid is used as a part of the condensate liquid, and a mixture of a part of the condensate liquid (particularly the condensate residual liquid) and the anti-gelling agent is used as the gelling agent solution. By making it act, the above-mentioned effects can be remarkably obtained.

In particular, in the presence of a dehydrating solvent, an acid catalyst and a polymerization inhibitor, the reaction product water produced during the esterification reaction is distilled together with the dehydrating solvent, and the distillate containing the reaction product water is condensed and liquefied. When the esterification reaction is carried out while the reaction product water is separated and removed from the condensed liquefied condensate, and the condensation residual liquid containing the dehydrated solvent after the reaction product water is separated and removed is returned to the reaction tank, By acting the anti-oxidant solution on the distillate, the above-mentioned effects can be obtained more remarkably, and further, the increase in the amount of the condensate residual liquid returned to the reaction tank can be suppressed as much as possible, so that the quality of the ester is higher. The compound can be efficiently produced at low cost.

Further, in the method for producing an esterified product according to the present invention, in particular, the gelation inhibitor solution is condensed in a region where the distillate containing the reaction product water is condensed and liquefied, that is, the liquefied distillate is discharged through the distillate route. Since the gel-like substance is generated by being adhered to the upper part, the action in this region can efficiently and effectively prevent the generation of the gel-like substance, and the above-mentioned action and effect can be more remarkably obtained.

Similarly, in the method for producing an esterified product according to the present invention, in particular, it is also efficient and effective to cause the gelation inhibitor solution to act near the top of the condenser for condensing and liquefying the distillate. To prevent the formation of gel-like substances,
The above-mentioned effects can be obtained more remarkably.

In the method for producing an esterified product according to the present invention, the anti-gelling agent solution is dissolved in the same solvent as the dehydrating solvent used for distilling the reaction product water as an azeotrope. By containing an anti-gelling agent in the form of a solution, it is possible to obtain the above-mentioned action and effect, and in the anti-gelling agent solution using such a polymerization inhibitor solution, a dehydrating solvent Since the distillate, which is an azeotrope, is soluble in the condensed and liquefied one, it has an advantage that it can be quickly acted by a contact method such as co-current contact. Also, even if these are refluxed and returned to the reaction tank, the composition of the distillate azeotroped from the reaction tank does not change, so the azeotropic temperature does not fluctuate, so temperature control in the reaction tank is easy. Yes, the control system does not become complicated.

In the apparatus for producing an esterified product according to the present invention, as a gelation preventing means, an antigelling agent solution containing at least a part of the condensate, preferably a part of the condensate residual liquid as a part of the condensate is used. Part, a gelling agent solution obtained by mixing a part of the condensate (particularly the condensate residual liquid) and the gelling agent (preferably the gelling agent in the form of a solution) is used as the distillate. By providing the gelation inhibitor supply mechanism to act, the same effects as those described above can be obtained. In addition, the esterified product obtained by using the device, impurities such as gel-like substances are effectively removed, the cement dispersant and the like using this, not only the dispersion performance, but also the slump retention performance and water reduction. It is also excellent in application performance such as performance and is advantageous in that it can be used as a monomer component useful as a raw material of a polymer which is a main component such as a cement dispersant.

Further, in the apparatus for producing an esterified product according to the present invention, as the gelation inhibitor supply mechanism, the nozzle section for acting the gelation inhibitor solution is located near the top of the condenser, that is, in the liquefied distillation column. By providing the gel-like substance on the part where the gel-like substance is generated by the adherence of the substance on the distilling route, the gel-like substance can be efficiently and effectively prevented from being generated, and the above-mentioned action and effect can be obtained more significantly. To be

Further, in the apparatus for producing an esterified product according to the present invention, since the nozzle portion is installed so as to be able to supply the anti-gelling agent solution upward, the results of Examples 1 and 4 above. As is clear from the above, the above-described effects can be obtained more remarkably.

Further, in the apparatus for producing an esterified product according to the present invention, as the gelation inhibitor supply mechanism, a first supply path for supplying the polymerization inhibitor solution from the storage section of the polymerization inhibitor solution to the nozzle section. Also, by providing the nozzle part with the second supply path for supplying a part of the condensate (particularly a part of the condensate residual liquid), the above-described effects can be sufficiently obtained.

[Brief description of drawings]

FIG. 1 is a schematic view of a typical apparatus configuration used in a method for producing an esterified product according to the present invention.

FIG. 2 is a schematic explanatory view showing an embodiment of a manufacturing apparatus of the present invention including a device configuration of a typical gelation inhibitor supply mechanism according to the present invention.

FIG. 3 is a schematic explanatory diagram showing a state in which a nozzle is installed in an overhead line immediately before a condenser.

FIG. 4 is a schematic explanatory diagram of a water separator that also serves as a storage unit.

FIG. 5 shows a first anti-gelling agent supply mechanism for supplying the anti-gelling agent solution from the storage section of the anti-gelling agent solution to the nozzle section, and a part of the condensate to the nozzle section. It is a schematic explanatory drawing which shows the 1st embodiment of arrangement | positioning relationship with a 2nd supply path.

FIG. 6 shows a first anti-gelling agent supply mechanism for supplying the anti-gelling agent solution from the storage section of the anti-gelling agent solution to the nozzle section, and a part of the condensate to the nozzle section. It is a schematic explanatory drawing which shows the 2nd embodiment of arrangement | positioning relationship with a 2nd supply path.

FIG. 7 shows a first anti-gelling agent supply mechanism for supplying the anti-gelling agent solution from the storage section of the anti-gelling agent solution to the nozzle section, and a part of the condensate to the nozzle section. It is a schematic explanatory drawing which shows the 3rd embodiment of the arrangement | positioning relationship with a 2nd supply path.

FIG. 8 shows a first anti-gelling agent supply mechanism for supplying the anti-gelling agent solution from the storage section of the anti-gelling agent solution to the nozzle section, and a part of the condensate to the nozzle section. It is a schematic explanatory drawing which shows the 4th embodiment of the arrangement | positioning relationship with a 2nd supply path.

FIG. 9 shows a first anti-gelling agent supply mechanism for supplying the anti-gelling agent solution from the storage section of the anti-gelling agent solution to the nozzle section, and a part of the condensate to the nozzle section. It is a schematic explanatory drawing which shows the 5th embodiment of the arrangement | positioning relationship with a 2nd supply path.

FIG. 10 shows a first anti-gelling agent supply mechanism for supplying the anti-gelling agent solution from the storage section of the anti-gelling agent solution to the nozzle section, and a part of the condensate to the nozzle section. It is a schematic explanatory drawing which shows the 6th embodiment of the arrangement | positioning relationship with a 2nd supply path.

FIG. 11 shows a first anti-gelling agent supply mechanism for supplying the anti-gelling agent solution from the storage section of the anti-gelling agent solution to the nozzle section, and a part of the condensate to the nozzle section. It is a schematic explanatory drawing which shows the 7th embodiment of the arrangement | positioning relationship with a 2nd supply path.

FIG. 12 is a first anti-gelling agent supply mechanism for supplying the anti-gelling agent solution from a storage section of the anti-gelling agent solution to the nozzle section, and a part of the condensate to the nozzle section. It is a schematic explanatory drawing which shows the 8th embodiment of the arrangement | positioning relationship with a 2nd supply path.

FIG. 13 shows a first anti-gelling agent supply mechanism for supplying the anti-gelling agent solution from the storage section of the anti-gelling agent solution to the nozzle section, and a part of the condensate to the nozzle section. It is a schematic explanatory drawing which shows the 9th embodiment of the arrangement | positioning relationship with a 2nd supply path.

FIG. 14 shows a first anti-gelling agent supply mechanism for supplying the anti-gelling agent solution from the storage section of the anti-gelling agent solution to the nozzle section, and a part of the condensate to the nozzle section. It is a schematic explanatory drawing which shows the 10th embodiment of the arrangement | positioning relationship with a 2nd supply path.

[Explanation of symbols]

101 ... reaction tank, 102, 150 ... jacket, 103 ... Raw material storage tank for alcohol, 105 ... Raw material storage tank for (meth) acrylic acid, 107 ... Catalyst storage tank, 109 ... Polymerization inhibitor storage tank, 111 ... Neutralizer storage tank, 113, 115, 117, 119, 121, 123, 129, 137, 139, 141 ... Piping, 145, 148, 149, 152, 153, 154, 156, 157, 161 ... Piping, 116, 146 ... Pump, 125 ... condenser, 126… spray nozzle, 127 ... water separator, 128 ... Storage tank, 131 ... partition plate, 133, 134 ... chamber inside the water separator, 135… Treatment water treatment tank, 142 ... Circulation pump, 143 ... Dehydration solvent storage tank, 147 ... Anti-gelling agent storage tank, 151 ... circulation path, 155 ... vacuum pump, 159 ... solvent storage tank, 501 ... reaction tank, 502 ... jacket, 503, 520-525 ... Piping, 505 ... Capacitor, 506 ... Nozzle part, 507 ... water separator, 508 ... Storage tank, 509 ... Polymerization inhibitor solution storage tank, 510-513 ... pump, 1a-1j ... 1st supply path, 2a to 2j ... Second supply path.

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) C07C 67/08 C07C 67/62 C07C 69/54 C08G 65/332 C04B 24/26

Claims (8)

(57) [Claims] 1. The following formula: (However, R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms, R ² O represents an oxyalkylene group having 2 to 18 carbon atoms, and the repeating units of each R ² O are the same. May be different or different, and when R ² O is in the form of a mixture of two or more kinds, the repeating units of each R ² O may be added in a block form or in a random form. , And n represents the average number of moles of oxyalkylene groups added, which is a number from 0 to 300), a reaction tank for carrying out an esterification reaction of an alcohol represented by (meth) acrylic acid, and the reaction tank. a capacitor, anti-gelling agent supply mechanism, and including non-picture esterification device a water separator for separating off water from the condensate resulting from the capacitor for condensing liquefying the distillate distilled from, This Antioxidant supply mechanism on connection pipe and / or between the reaction tank and the condenser
It is provided in at least one location in the capacitor, small
An anti-gelling agent solution containing at least part of the condensate
An esterification device characterized by acting on distillate . Wherein said anti-gelling agent supply mechanism is anti-gelling agent supply mechanism provided in the top vicinity of the nozzle part for acting the antigelling agent solution capacitor device according to claim 1. Wherein said nozzle portion is disposed so as to be able to upwardly supply the antigelling agent solution, according to claim 2. 4. The first anti-gelling agent supplying mechanism supplies the anti-gelling agent from the anti-gelling agent storage section to the nozzle section.
The apparatus according to any one of claims 1 to 3 , comprising a supply path and a second supply path for supplying a part of the condensate to the nozzle portion. 5. The formula (1), n represents an average addition mol number of oxyalkylene groups, the number of 2 to 300, according to any one of claims 1 to 4. Wherein said anti-gelling agent solution comprises an anti-gelling agent in a portion with a solution and / or solid form of condensate, Apparatus according to claim 1. 7. The device according to claim 1, wherein the anti-gelling agent is caused to act in a form mixed with a solvent of the same kind as the dehydrating solvent.
Place 8. under following formula: ## STR2 ## (However, R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms, R ² O represents an oxyalkylene group having 2 to 18 carbon atoms, and the repeating units of each R ² O are the same. May be different or different, and when R ² O is in the form of a mixture of two or more kinds, the repeating units of each R ² O may be added in a block form or in a random form. , And n represents the average number of moles of oxyalkylene groups added, which is a number of 1 to 300). The alkoxypolyalkylene glycol represented by (meth) acrylic acid is esterified with (alkoxypolyalkylene glycol). A mono (meth) acrylic acid-based monomer (a) is obtained, and the alkoxypolyalkylene glycol mono (meth) acrylic acid-based monomer (a) is obtained.
5 to 98% by mass, the following formula (2): (However, R ³ represents hydrogen or a methyl group, and M ¹ represents hydrogen, a monovalent metal, a divalent metal, an ammonium group or an organic amine group.) (Meth) acrylic acid-based monomer (b) 95 to 2% by mass, and 0 to 50% by mass of another monomer (c) copolymerizable with these monomers (however,
(A), (b) and (c) are 100% by mass in total) , and the above-mentioned alkoxypolyalkylene glycol mono is a polycarboxylic acid-based copolymer for cement dispersant obtained by copolymerization.
The production of the (meth) acrylic acid-based monomer (a)
The device of claim 1, which is a signature .