JP3537707B2 - Apparatus for producing alkoxypolyalkylene glycol mono (meth) acrylate and production method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing an alkoxypolyalkylene glycol mono (meth) acrylate (hereinafter also referred to simply as an esterified product) and a production method using the same. . More specifically, an apparatus for producing an esterified product applicable to a raw material monomer of a high-performance cement dispersant by an esterification reaction between an alkoxypolyalkylene glycol and (meth) acrylic acid, and a production method using the same It is about.

[0002]

2. Description of the Related Art Since the early deterioration of concrete structures became a social problem in 1981, there has been a strong demand to reduce the unit water content in concrete to improve its durability and workability. A cement composition which satisfies the above, especially a cement dispersant which has a great influence on its quality and performance, has been actively developed.

[0003] Among them, a copolymer of a polyalkylene glycol mono (meth) acrylate monomer and a (meth) acrylate monomer is disclosed in JP-B-59-1833.
No. 8 discloses a high-performance concrete having at least a high amount of water-reducing performance and a high strength of concrete with high water-reducing performance, and further excellent durability and workability. High fluidization can also be achieved. Various alkoxypolyalkylene glycol mono (meth) acrylate monomers, which are the raw materials of copolymers used in such high-performance cement dispersants, are obtained by esterifying alkoxypolyalkylene glycol and (meth) acrylic acid. It is obtained by reacting. In such an esterification reaction, reaction product water is produced as a by-product, and unless the reaction product water is removed from the reaction tank, the reaction does not proceed in a direction of generating an esterified product due to an equilibrium reaction. Therefore, for example, as disclosed in JP-A-9-328346, various alkoxypolyalkylene glycol mono (meth) acrylate monomers serving as raw materials of a copolymer used for a cement dispersant are synthesized. However, a method has been adopted in which a water separator is provided so that water produced by the reaction can be separated.

[0004] However, as disclosed in the above-mentioned publication, there is no particular disclosure other than providing a water separator for separating and removing water produced by the reaction during the esterification reaction. At present, there are no reports on technical issues in industrialization, etc. to date.

[0005]

Accordingly, the present inventors have developed an alkoxypolyalkylene glycol mono (meth) acrylate which can be used as a raw material monomer for a high-performance cement dispersant by using a large-scale production apparatus. As a result of repeated experiments in the case of continuous mass production, a large amount of distillate that was condensed appropriately in the glass tube to the water separator with a small distilling flow rate or flow rate at the laboratory level was found. As a result, the water may not be completely condensed and may be sent into the water separator in a partially condensed state where the condensation is not complete, which has the following problems.

[0006] 1. Internal pressure rises. As a result, the azeotropic temperature is lowered and the distillation rate is suppressed, so that it is necessary to raise the internal temperature. The same problem occurs. There is a problem with the pressure resistance of the device under pressurized conditions.

[0007] 2. If the apparatus is an open system so as not to be pressurized, a problem arises because the dehydrating solvent gradually decreases. Since the dehydrating solvent escapes outside the system, the amount of the dehydrating solvent returning to the reaction tank decreases, and the amount of the dehydrating solvent decreases (the removal efficiency of water produced by the reaction decreases, so that the esterification time significantly increases). There is a problem that the temperature rises (impurities are formed due to the rise in the internal temperature, which acts as a crosslinking agent in the polymerization reaction in the next step to produce a high molecular weight crosslinked product having poor cement dispersibility).

Further, when mass production is continuously performed by a large-scale production apparatus, water separation that has not occurred (or has not been realized) when continuous production is not performed as in a laboratory level. The formation of a gel-like substance on the distilling route to the vessel became apparent, and further adhered to the inner wall of the route and gradually increased with time. In the worst case, there was a possibility that blockage might occur. Repeat the device (so to speak,
During operation, the heat exchange rate gradually decreases due to the deposition of the gel-like substances, and it becomes more difficult to completely condense the gaseous distillate. In order to avoid such a situation, it is necessary to frequently stop the operation and clean the inside of the apparatus to remove the gel-like substance so as not to cause such a situation. In addition, a part of the attached gel-like substance flows down during operation, is refluxed with the dehydrating solvent, stays as an impurity in the reaction tank, and is finally mixed into the cement dispersant,
There was also a problem of deteriorating the performance and quality of the cement dispersant.

Accordingly, an object of the present invention is to solve the above-mentioned problems by continuously producing a large amount of alkoxypolyalkylene glycol mono (meth) acrylate which can be used as a raw material monomer of a high-performance cement dispersant. An object of the present invention is to provide a large-scale manufacturing apparatus suitable for production and a manufacturing method using the same.

That is, an object of the present invention is to provide a raw material for a high-performance cement dispersant which is completely condensed before a gaseous distillate enters a water separator in continuous mass production. An object of the present invention is to provide a large-scale apparatus for producing an alkoxypolyalkylene glycol mono (meth) acrylate which can be applied and a production method using the same.

[0011] Another object of the present invention is to cause a blockage of a flow path and a total condensation failure due to a decrease in heat exchange efficiency due to adhesion and deposition of a gel-like substance in continuous mass production. Suitable for mass production of stable and continuous operation of alkoxypolyalkylene glycol mono (meth) acrylate which can be used as a raw material monomer for high-performance cement dispersants. A large-scale manufacturing apparatus and a manufacturing method using the same are provided.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above technical problems, and as a result, have found that in continuous mass production of alkoxypolyalkylene glycol mono (meth) acrylic acid ester, The inventors have found that there is a useful and effective correlation between the volume of the tank and the heat transfer area of the condenser to obtain a large-scale industrially usable device, and have completed the present invention. .

That is, the object of the present invention is to provide the following (1)
The present invention is achieved by an apparatus for producing an esterified product described in (3) to (3) and a production method using the same.

(1) The ratio of the heat transfer area of the condenser for condensing and liquefying the distillate containing reaction product water distilled from the reaction tank to the volume of the reaction tank for performing the esterification reaction is as follows:
An apparatus for producing an alkoxypolyalkylene glycol mono (meth) acrylate applicable to a raw material monomer of a cement dispersant, which is in the range of 1.0 to 20.0 m ^-1 .

(2) The production apparatus according to the above (1), further comprising a mechanism and / or means for preventing generation of a gel derived from the distillate.

(3) Using the production apparatus described in the above (1) or (2), the general formula R ¹ O (R ² O) _n H ( _where R ¹ is a carbon atom having 1 to 30 carbon atoms) of a hydrocarbon group, R ² O represents an oxyalkylene group having 2 to 18 carbon atoms, this time, the repeating units of the R ² O may be the even or different the same, and R ² When 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 block form or in random form, and n is the average addition of oxyalkylene groups. Mole number, which is a number from 1 to 300), wherein the esterification reaction of the alkoxypolyalkylene glycol and (meth) acrylic acid is carried out. The alkoxypolyalkyl obtained Method for producing a glycol mono (meth) acrylic acid ester.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An apparatus for producing an alkoxypolyalkylene glycol mono (meth) acrylate applicable to a raw material monomer of a cement dispersant according to the present invention is characterized in that the reaction with respect to the volume of a reaction tank in which an esterification reaction is carried out. The ratio of the heat transfer area of the condenser for condensing and liquefying the distillate containing reaction water distilled from the tank (= heat transfer area of the condenser / volume of the reaction tank) is in the range of 1.0 to 20 m ^-1 . Is characterized in that:

[0018] In the apparatus of the present invention, after a new condenser is provided between the reaction tank and the water separator, the reaction product water distilled from the reaction tank relative to the volume of the reaction tank for performing the esterification reaction is included. The ratio of the condenser for condensing and liquefying the distillate is 1.0 to 20.0 m ^-1 , preferably 3.5 to 7.0.
m ^-1, more preferably 4.0~6.5m ^-1, particularly preferably by the range of 4.5~6.0m ^-1, applied to the raw material monomer of high-performance cement dispersant This has the advantage that the possible alkoxypolyalkylene glycol mono (meth) acrylate can be continuously mass-produced. That is, it is possible to provide a large-scale apparatus that is excellent in industrial use (including productivity and economy). By satisfying the above requirements, the distillate can be completely condensed in the condenser before the gaseous distillate enters the water separator. As a result, it is possible to solve the above-mentioned problem that has occurred when the scale of the laboratory configuration is increased. That is, since the gaseous distillate is completely condensed by the condenser before entering the water separator, the distillation speed is stabilized without causing a pressure increase, and the reaction time can be prevented from being prolonged. Also, there is no possibility of destruction or breakage without using a pressure-resistant member. In addition, since high-temperature gaseous distillate does not enter the water separator, the members are not exposed to high temperatures and degrade or break due to the accumulation of thermal fatigue without using heat-resistant members. Never even. If the ratio of the heat transfer area of the condenser to the volume of the reaction vessel is less than 1.0 m ⁻¹ , the above-described problems occur because the capacity of the condenser is insufficient with respect to the reaction vessel. The distillation rate of the distillate must be suppressed, the reflux rate of the solvent cannot be increased, and the reaction time is longer. Absent. On the other hand, when the ratio of the heat transfer area of the condenser to the volume of the reaction tank exceeds 20.0 m ⁻¹ , the equipment cost and running cost of the condenser are increased (for a condenser having excess capacity, a large amount of cooling medium is required). In addition, it is necessary to use a larger pump for supplying cooling medium and a circulating pump, etc., that are compatible with the condenser having the excess capacity.) Is not preferred.

The apparatus of the present invention is preferably further provided with a mechanism and / or means for preventing generation of a gel derived from distillate. As a mechanism for preventing generation of a gel-like substance derived from a distillate (= caused by a distillate), for example, (a) a distilling path between a reaction tank and a condenser (hereinafter, also simply referred to as an overhead line) A) an anti-gelling agent supply mechanism for causing an anti-gelling agent containing a polymerization inhibitor to act in at least a part of the condenser and / or a condenser; and (b) means for heating and / or keeping the temperature of at least a part of the overhead line. Can be illustrated.

In the apparatus of the present invention, by providing a mechanism and / or means for preventing the generation of a gel-like substance derived from a distillate, the adhesion of the gel-like substance, Alkoxy polyalkylene glycol mono (meth) which can be used as a raw material monomer for a high-performance cement dispersant without causing blockage of the distilling path and total condensation failure due to a decrease in heat exchange efficiency due to the deposition. The acrylate ester can be operated stably for a long period of time, and can be maintenance-free for a long period of time.

The mechanism for supplying the anti-gelling agent (a) is to directly feed an anti-gelling agent solution (usually used in the form of a solution in which a polymerization inhibitor is dissolved in an appropriate solvent) to the distillate. Spraying the anti-gelling agent solution,
A nozzle unit for blowing, blowing, discharging, blowing up, and lowering is provided in at least a part of the overhead line and / or inside the condenser, preferably near the top of the condenser, that is,
It is desirable to be provided inside the tower top of the condenser, inside the overhead line immediately before the condenser, inside the overhead line just above the reaction tank (= at the base at the reaction section side), and the like. In addition, it is desirable to adjust the mounting direction of the nozzle portion depending on the installation location so that the gelling inhibitor solution can efficiently act on the distillate. The top of the condenser where the material is generated (= distillate inlet)
It should be installed upward at the top of the condenser or at the center in the overhead line just before the condenser so that the inner wall of the condenser can be constantly wetted. As a result, the gelling agent solution can be very effectively and effectively generated as a gel directly or indirectly through the wall of the overhead line immediately before the condenser or directly on the inner wall at the top of the condenser. It can act on the inner wall of the top.

As one embodiment of the above-mentioned anti-gelling agent supply mechanism (a), a polymerization inhibitor solution (a solution in which a polymerization inhibitor is dissolved in an appropriate solvent; if this solution is used alone, 1 or 2 provided at the above and / or position from the reservoir of the solution becomes an anti-gelling agent solution)
Only the first supply path (a suitable pipe and a pressure pump can be used) for supplying the polymerization inhibitor solution may be provided for each of the nozzles, or a part of the condensate may be supplied to the nozzles. And a second supply path (appropriate piping and a pressure pump can be used).
The second supply path may be any path that connects the distilling path (particularly the circulation path) for sending the condensed liquid (particularly the condensed residual liquid) and the nozzle section. For example, the second supply path is directly or the first supply path. It is only necessary that the nozzle unit is indirectly connected to the nozzle unit by merging with the nozzle unit. Further, if necessary, a storage unit is provided on a distilling path (particularly, a circulation path), and the storage unit and the nozzle unit are provided. And may be tied. Examples of the storage unit include a storage tank and a part of a water separator provided on a circulation path between the water separator and the reaction tank for temporarily storing condensed residual liquid. Preferably, the first and second supply paths of the anti-gelling agent supply mechanism are provided with means capable of arbitrarily adjusting the flow rates of a part of the polymerization inhibitor solution and the condensate,
A suitable flow control valve can be exemplified. This makes it extremely easy to adjust the flow rates of the polymerization inhibitor solution and a part of the condensate. When the first supply path and the second supply path are merged, if necessary, on one path after the merge,
A means for mixing or stirring the polymerization inhibitor solution and a part of the condensate may be provided, and examples thereof include a baffle plate and a protrusion formed on the inner wall of the path immediately after the junction. Thereby, the polymerization inhibitor solution and a part of the condensate can be mixed more quickly and uniformly. Further, when the first supply path and the second supply path are directly connected to the nozzle section, the polymerization inhibitor solution and a part of the condensate are rapidly stirred and mixed in the nozzle section. It is preferable to use a nozzle having an internal structure.

Here, the term "condensate" refers to one that comes out of the outlet of the condenser. In addition, since the anti-gelling agent solution applied before the outlet of the condenser also comes out of the outlet of the condenser, the anti-gelling agent solution is also included in the condensate. Furthermore, since the condensed residue and the separated water are then separated by a water separator, both the condensed residue and the separated water are one type of condensed liquid, and they can be used independently of each other. The term "part of the condensate" includes not only a part of the condensate but also a condensate remaining liquid obtained by separating the condensate and a part of the condensate. Further, “condensation residue” refers to a component on the solvent side separated by a water separator, and “separated water” refers to a component on the water side separated by a water separator that is a water separation unit. The components on the solvent side include, in addition to the gelling agent solution, a dehydrating solvent used as necessary. The components on the water side include reaction product water and raw materials. The condenser and the water separator are used as follows in the apparatus for producing an esterified product of the present invention (and the production method using the same). That is, in the present invention,
It is necessary to distill the reaction water generated during the esterification reaction from the reaction tank, but since the distillate contains components other than the reaction water as described above, it is not possible to directly release it to the atmosphere. Since such reaction water cannot be produced due to problems such as environmental pollution, it is necessary to appropriately treat or reuse such water after distilling out the reaction product water from the reaction tank. Then, 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, where it is separated into two layers by utilizing the difference in its properties, and the separated water consisting of the water component of one layer and the separated water of the other layer It is used to separate the condensate from the solvent.

The gelling inhibitor solution only needs to contain a polymerization inhibitor. For example, a part of the above condensate, a polymerization inhibitor solution, or the like can be used alone or in combination. Further, other additives, for example, an acid catalyst which is appropriately added for the purpose of replenishing the inside of the reaction tank may be contained.

At least a part of the overhead line (b), preferably at least 25%, more preferably at least 50%, even more preferably at least 75% of the overhead line to which the polymerization inhibitor supply mechanism is not applied is heated and / or heated. Means for keeping the temperature is not particularly limited. When heating using a heating heater such as a heating wire (copper wire) coil or the like, the overhead line is made into a double pipe, and the distillate is stored in the inner pipe. When a medium (pressurized steam, oil, heated gas such as combustion exhaust gas, etc.) is passed through the outer pipe and heating and keeping the temperature and flow of the medium properly adjusted, a material with high heat retention such as glass wool May be used to keep warm. Also, if necessary,
These means may be appropriately combined. Further, an optimal gelling prevention means may be used for each portion of the overhead line.

The production apparatus of the present invention is not particularly limited except for the essential component of the ratio of the heat transfer area of the condenser to the volume of the reaction tank described above. A mechanism and / or means for preventing generation of a gel-like substance may be further provided, and a conventionally known esterification reaction apparatus (for example, a stirring device or heating means provided in a reaction vessel, a heating means, Use of various storage tanks such as raw material storage tanks, catalyst storage tanks, and solvent storage tanks, and connecting pipes, pressure pumps, reaction devices such as flow control valves and switching valves, and mechanisms / means, etc. Can be.
In addition, Japanese Patent Application No. 10-2681 previously proposed by the present inventors.
No. 21-Japanese Patent Application No. 10-268124, Japanese Patent Application No. 10-3
28683-Japanese Patent Application No. 10-328687, Japanese Patent Application No. 1
The manufacturing technique described in 1-99335 can be appropriately used.

Further, a method for producing an alkoxypolyalkylene glycol mono (meth) acrylate which can be used as a raw material monomer of the cement dispersant of the present invention is carried out by using the above-described production apparatus and the general formula R ¹ O (R ² O) _n H
(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 a repeating unit of each R ² O is May be the same or different and R
^{When 2} O is in the form of a mixture of two or more, each R ² O
May be added in block form or in random form, and n represents the average number of moles of oxyalkylene group added, and is a number of 1 to 300. ), And performing an esterification reaction between the alkoxypolyalkylene glycol and (meth) acrylic acid.

In the production method of the present invention, by using a production apparatus that satisfies the above-described ratio of the heat transfer area of the condenser to the volume of the reaction tank, the production method can be applied to a high-quality and high-performance cement dispersant as a raw material monomer. The obtained alkoxypolyalkylene glycol mono (meth) acrylate is excellent in productivity and economic efficiency, and can continuously mass-produce a product (intermediate) excellent in industrial applicability.

Further, in the manufacturing method of the present invention, the outlet temperature of the cooling medium of the condenser is set to the inlet temperature + 0.01 to 50 ° C.
, Preferably in the range of +0.1 to 30 ° C. inlet temperature,
More preferably, it is desirable to adjust the inlet temperature to a range of +1.0 to 20 ° C.

As a preferred embodiment of the production method of the present invention other than the requirements described above, a method of the general formula R ¹ O (R ² O) _n H in the presence of a dehydrating solvent, an acid catalyst and a polymerization inhibitor is described. Alkoxypolyalkylene glycol shown and (meth)
A method for producing an alkoxypolyalkylene glycol mono (meth) acrylic ester applicable to a raw material monomer of a high-performance cement dispersant by an esterification reaction with acrylic acid, the reaction being formed during the esterification reaction The water is distilled off together with the dehydrating solvent, the distillate containing the reaction product water and the dehydrating solvent is condensed and liquefied by a condenser, and the reaction product water is separated and removed from the condensed liquid condensed and liquefied by a water separator,
An esterification reaction is performed (esterification step) while returning the condensed residue containing the dehydrated solvent after separating and removing the reaction product water to the reaction tank (esterification step). After the esterification reaction is completed, the acid catalyst or all of the acid catalyst ( Neutralizing a part of (meth) acrylic acid (partial neutralization step), then distilling off the dehydrating solvent from the reaction solution by azeotropic distillation with water (solvent distilling step), and dispersing the desired high-performance This is a method for obtaining an alkoxypolyalkylene glycol mono (meth) acrylate applicable to the raw material monomer of the agent.

(I) Description of the Esterification Step A preferred embodiment of the esterification step will be described below.

Using a production apparatus which satisfies the above-mentioned ratio of the heat transfer area of the condenser to the volume of the reaction tank, first, an alkoxypolyalkylene glycol of the general formula R ¹ O (R ² O) _n H and (Meth) acrylic acid, preferably a dehydrating solvent, an acid catalyst and a polymerization inhibitor are charged, and the mixture is subjected to an esterification reaction at a predetermined temperature until a predetermined esterification ratio is reached. At this time, the reaction product water generated during the esterification reaction is distilled out of the reaction tank together with the dehydrating solvent, and the distillate containing the reaction product water and the dehydrating solvent is totally condensed by a condenser and condensed and liquefied by a water separator. The reaction product water is separated and removed from the liquid, and the condensed residue after separation and removal of the reaction product water is refluxed and returned to the reaction tank (hereinafter, a system for performing these series of operations is also referred to as a circulation system). ).

Here, in the alkoxypolyalkylene glycol represented by the above general formula R ¹ O (R ² O) _n H which is one of the raw materials used in the production method of the present invention, R
¹ represents a hydrocarbon group having 1 to 30, preferably 1 to 18 carbon atoms. Examples of R ¹ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a nonyl group, a 2-ethylhexyl group, and a decyl group. , An alkyl group such as dodecyl group, undecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, heneicosyl group, docosyl group;
An aryl group such as a phenyl group; an alkylphenyl group such as a benzyl group and a nonylphenyl group; a cycloalkyl group such as a cyclohexyl group; an alkenyl group; Of these, methyl group, ethyl group,
Propyl, butyl and phenyl groups are preferred.

R ² O represents an oxyalkylene group having 2 to 18, preferably 2 to 8 carbon atoms. Particularly, R ² O is preferably an oxyethylene group, an oxypropylene group and an oxybutylene group. The repeating units of R ² O may be the same or different, and when two or more kinds of different repeating units are present, they may be added in a block shape or in a random shape. May be.

Further, n is 1 to 300, preferably 5 to
It is the number of 150, and represents the average number of moles of repeating units of R ² O (oxyalkylene group). When n exceeds 300, the polymerizability of the esterified product of the compound of the general formula R ¹ O (R ² O) _n H and (meth) acrylic acid decreases.

The alkoxypolyalkylene glycol represented by the above general formula R ¹ O (R ² O) _n H may be used alone or in the form of a mixture of two or more. The form of use of the mixture of two or more alkoxypolyalkylene glycols represented by the general formula R ¹ O (R ² O) _n H is not particularly limited, and R ¹ , R ² O
Or n may be a use form of a mixture of two or more kinds in which at least one of n is different, and preferably R ¹
Is composed of two types, a methyl group and a butyl group,
When R ² O is composed of two types, an oxyethylene group and an oxypropylene group, those in which n is 1 to 10 and 11 to 11
If it is composed of two of the 100, and ~
Are appropriately combined.

Next, with respect to the (meth) acrylic acid used in the production method of the present invention, acrylic acid and methacrylic acid may be used alone or in combination. Any range can be adopted for.

The mixing ratio of the alkoxypolyalkylene glycol represented by the above general formula R ¹ O (R ² O) _n H and (meth) acrylic acid used in the production method of the present invention is stoichiometric. Although it is 1: 1 (molar ratio), it is not particularly limited as long as the esterification reaction proceeds efficiently. Usually, one of the raw materials is excessively used to accelerate the esterification reaction, From the viewpoint of purification of the esterified product, an excess of a raw material having a lower boiling point which is easily distilled off may be used. The amount of (meth) acrylic acid to be used is generally 1.0 to 30 mol, preferably 1.2 to 10 mol, per mol of the alkoxypolyalkylene glycol.
Is a mole. If the amount of the (meth) acrylic acid is less than 1.0 mol per 1 mol of the alkoxypolyalkylene glycol, the esterification reaction does not proceed smoothly, and the desired alkoxypolyalkylene glycol mono (meth)
When the yield of the acrylate ester is insufficient, and when it exceeds 30 moles, the yield improvement corresponding to the addition is not recognized,
It is uneconomical and unfavorable.

When the esterification reaction of the present invention is carried out in the presence of an acid catalyst, the reaction can proceed rapidly. Acid catalysts that can be used include, for example, sulfuric acid, methanesulfonic acid, paratoluenesulfonic acid, xylenesulfonic acid, naphthalenesulfonic acid, trifluoromethanesulfonic acid, “Nafion” resin,
"Amberlyst 15" resin, phosphotungstic acid, hydrochloric acid and the like are used in the form of a hydrate and / or an aqueous solution. These may be used alone or as a mixture of two or more. Further, an acid catalyst which does not easily break the alkoxypolyalkylene glycol raw material is more preferable, and specifically, paratoluenesulfonic acid is used in the form of a hydrate and / or an aqueous solution.

The amount of the acid catalyst used is not particularly limited as long as the desired catalytic action can be effectively exhibited, but is preferably 0.4 meq / g.
Or less, more preferably 0.36 to 0.01 meq / g, particularly preferably 0.32 to 0.05 meq / g.
g. The amount of acid catalyst used is 0.4 meq /
If the amount exceeds g, the amount of diester formed in the reaction tank during the esterification reaction increases, and the cement dispersing ability of the cement dispersant synthesized using the esterified product obtained by the esterification reaction decreases. Here, the amount of use of the acid catalyst (milli-equivalent / g) refers to the number of equivalents (milli-equivalent) of H ⁺ of the acid catalyst used in the reaction, which is a raw material of alkoxypolyalkylene glycol (hereinafter, simply abbreviated as alcohol).
And (meth) acrylic acid divided by the total charge (g). More specifically, it is a value calculated by the following equation.

[0041]

(Equation 1)

When the acid catalyst is used in the form of a hydrate and / or an aqueous solution, the amount of the acid catalyst used is based on the total weight of the raw material alcohol and (meth) acrylic acid. When the weight ratio of the acid is X (% by weight) and the weight ratio of the hydrate and / or water present as an aqueous solution in the acid catalyst is Y (% by weight),
It is more desirable to satisfy the relationship of <Y <1.81X-1.62. However, an acid component other than the acid catalyst (for example, (meth) acrylic acid as a raw material) and water (for example, water generated by an esterification reaction) cannot be an object of X and Y described herein. This makes it possible to reduce the side effect of cutting the alcohol raw material while maintaining the catalytic function of the acid catalyst sufficiently, and to obtain an esterified product of extremely high quality, which is extremely useful as a raw material for a cement dispersant. it can.

The method of adding the acid catalyst to the reaction tank may be performed all at once, continuously or sequentially, but from the viewpoint of workability, it is preferable to charge the reaction tank together with the raw materials in the reaction tank.

It is desirable that the esterification reaction is performed in the presence of a polymerization inhibitor. By using a polymerization inhibitor, polymerization of the raw material alcohol and (meth) acrylic acid, an esterified product of the product, or a mixture thereof can be prevented. As the polymerization inhibitor that can be used in the esterification reaction, a known polymerization inhibitor can be used, and is not particularly limited. Examples thereof include phenothiazine, tri-p-nitrophenylmethyl, and di-p-fluoro. Phenylamine, diphenylpicrylhydrazyl, N- (3-N-oxyanilino-1,3-dimethylbutylidene) aniline oxide, benzoquinone, hydroquinone, methoquinone, butylcatechol, nitrosobenzene, picric acid, dithiobenzoyldisulfide, cupperon, Copper (II) chloride and the like can be mentioned, and these polymerization inhibitors may be used alone or in combination of two or more. Phenothiazine, hydroquinone, and methoquinone are preferably used because of the solubility of the reaction water and the dehydrating solvent. Particularly, when the acid catalyst is used in the form of a hydrate and / or an aqueous solution, the aqueous solution present in the reaction vessel is preferably used. In addition to being able to function effectively with respect to the gel-forming substance described above, the polymerization inhibiting ability can be extremely effectively exerted even in the solvent distillation step as described later.

The amount of the polymerization inhibitor is 0.001 to 1% by weight, preferably 0.001 to 1% by weight based on the total amount of the alcohol and (meth) acrylic acid used as the raw materials.
It is in the range of 0.1% by weight. If the amount of the polymerization inhibitor is less than 0.001% by weight, the polymerization inhibitory ability is not sufficiently exhibited, and if it exceeds 1% by weight, the amount of the polymerization inhibitor remaining in the esterified product increases. Therefore, it is not preferable in terms of quality and performance.

Further, 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 that the reaction product water can be distilled out of the reaction tank at a lower temperature from the viewpoint of handling. . In the present specification, a dehydrated solvent is defined as a solvent that azeotropes with water. That is, by using a dehydration solvent, the reaction water generated by the esterification reaction can be efficiently azeotroped. As the dehydrating solvent, for example, benzene, toluene, xylene, cyclohexane, dioxane, pentane, hexane, heptane, chlorobenzene,
Examples thereof include isopropyl ether, and these can be used alone or as a mixed solvent of two or more kinds. Of these, the azeotropic temperature with water is 200 ° C
Hereinafter, the temperature is more preferably in the range of 50 to 150 ° C., and still more preferably 60 to 100 ° C., and specific examples include cyclohexane, toluene, and isopropyl ether. When the azeotropic temperature with water exceeds 200 ° C., it is not preferable in terms of handling.

The dehydrated solvent is distilled off together with the reaction water from the reaction tank, condensed and liquefied by a condenser, and refluxed while separating and removing the reaction water by a water separator. The amount of the dehydrating solvent used is 1 to 1 with respect to the total charged amount of alcohol and (meth) acrylic acid as raw materials.
00% by weight, preferably in the range of 2 to 50% by weight. If the amount of the dehydrating solvent is less than 1% by weight, the reaction water cannot be sufficiently removed, which is not preferable. If the amount of the dehydrating solvent exceeds 100% by weight, the effect corresponding to excessive addition cannot be obtained. Not preferred.

In the esterification reaction of the present invention, the esterification reaction can be carried out without using a dehydrating solvent and without using a solvent. In this case, air or inert gas (nitrogen gas,
It is necessary to perform a bubbling process using a gas such as helium gas, argon gas, or carbon dioxide (preferably, a gas containing no water vapor). As such a bubbling process, for example, a gas (bubble) is continuously blown into the reaction solution from an air nozzle or the like provided at a lower portion in the reaction tank,
In the process of passing through the reaction solution, water in the reaction solution is taken into bubbles, and a vapor-containing gas that has passed through the reaction solution is distilled out of the reaction tank.
The present invention is not particularly limited to this, and can be used by appropriately selecting a conventionally known bubbling method and combining it as necessary.

In the present invention, the esterification reaction can be carried out in either a batch system or a continuous system, but is preferably carried out in a batch system.

The reaction conditions for the esterification reaction may be any conditions under which the esterification reaction proceeds smoothly, and the reaction temperature is 30 to 140 ° C., preferably 60 to 13 ° C.
The temperature is 0 ° C, more preferably 90 to 125 ° C, particularly preferably 100 to 120 ° C. If the reaction temperature is lower than 30 ° C., the esterification reaction hardly proceeds, and it takes time to dehydrate (distill) the reaction product water, which undesirably increases the time required for the esterification reaction. Conversely, the reaction temperature is 140 ° C
Exceeding the above range will cause an excessive amount of diester to be generated due to the cutting of the alcohol raw material, and the dispersing performance and the thickening property in various applications will decrease in addition to the cement dispersing performance. Furthermore, the esterification reaction according to the present invention may be performed under normal pressure or under reduced pressure, but it is preferable to perform the esterification reaction under normal pressure from the viewpoint of facilities.

The esterification rate in the esterification reaction according to the present invention is 70% or more, more preferably 70 to 99.
%, Most preferably 80-98%. If the esterification rate is less than 70%, the yield of the produced esterified product is insufficient, and the performance of the cement dispersant or the like obtained using the esterified product as a raw material, for example, the cement dispersing ability or the like is reduced. Incidentally, the `` esterification ratio '' used in the present specification is a value calculated by the following formula by measuring the amount of reduction of the alcohol as the starting material for esterification under the esterification measurement conditions shown below. It is defined.

[0052]

(Equation 2)

Esterification ratio measurement conditions Analyzer: Waters Millennium chromatography manager Detector: Waters 410 RI detector Column used: GL Sciences Inertsil ODS-2 3 columns Temperature: 40 ° C. Eluent: 8946 g of acetonitrile 6000 g acetic acid 54 g were mixed and adjusted to pH 4.0 with a 30% aqueous sodium hydroxide solution. Flow rate: 0.6 ml / min Since the esterification rate was determined by the above formula, the esterification rate was 100%. Never go over. Therefore, in the present invention, it is assumed that the esterification reaction has been completed when the esterification rate has exceeded the specified value (maximum 100%).

Further, when a dehydrating solvent is used, it is desirable that the reaction temperature during the esterification reaction be 130 ° C. or less and the solvent circulation rate during the esterification reaction be 0.5 cycles / hour or more. Accordingly, there is no need to raise the reaction temperature to the impurity formation temperature region (region exceeding 130 ° C.) to perform 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 distilled off from the reaction tank without stagnating in the reaction tank for a long time, and the reaction time can be shortened because the equilibrium reaction proceeds in the direction of esterification.

Here, the solvent circulation rate during the esterification reaction in the present specification is defined as follows. That is, during the esterification reaction, the dehydrated solvent in the reaction tank is returned from the reaction tank to the reaction tank through the circulation path and circulated with respect to the total amount (volume amount) of the dehydration solvent charged in the reaction tank. The cycle when the amount (volume amount) corresponding to the total amount of the dehydrated solvent charged in step 1 is circulated is defined as one cycle, and the solvent circulation rate during the esterification reaction is expressed by the number of cycles per unit time (1 hour) And the unit is “cycle / time”. Therefore, for example, when 15 times the amount corresponding 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.

The above-mentioned reaction temperature and solvent circulation rate are based on the heating method (means) for the reaction tank, the temperature (calorific value) applied to the reaction tank using the apparatus, the amount of the dehydrating solvent used for the raw materials charged into the reaction tank, and the like. Can be adjusted to a desired range. The reaction temperature must not exceed the upper limit temperature specified above regardless of the position and time conditions at any position and time. It was made.

In the esterification step of the present invention, an esterification reaction is carried out by using a device and / or means for preventing the formation of a gel derived from distillate in the above-mentioned production apparatus. It is desirable to perform, for example,
(A) at least part of the distillation path (overhead line) between the reaction tank and the condenser and / or the action of a gelling inhibitor solution containing a polymerization inhibitor on the condenser, or (b) at least part of the overhead line. It is desirable to heat and / or keep it warm.

The polymerization inhibitor used when a gelling inhibitor solution containing a polymerization inhibitor is allowed to act on at least a portion of the overhead line (a) and / or the condenser includes a low-boiling material in the distillate. It is only necessary to be able to suppress the polymerization reaction, and it can be appropriately selected from conventionally known polymerization inhibitors and used, and the same polymerization inhibitor to be added to the reaction tank at the time of the esterification reaction is used. Available.

The amount of the polymerization inhibitor used effectively prevents the formation of a gel-like substance with respect to the low-boiling-point raw materials which are sequentially distilled from the start of distillation of the distillate to the end of the esterification reaction. In the case where a dehydrating solvent is required for the esterification reaction, and the dehydrating solvent is distilled off and refluxed, the amount of the distillate that can be obtained (the cumulative amount from the start of distillation of the distillate to the end of the esterification reaction) is required. Further, from the viewpoint that it is necessary to minimize the amount of the polymerization inhibitor used, the amount of the polymerization inhibitor is 0.1 to 1 with respect to the amount of the alcohol and (meth) acrylic acid used as raw materials.
000 ppm by weight, preferably in the range of 1 to 500 ppm by weight. If the amount is less than 0.1 ppm by weight, a large amount of a gel-like substance may be formed. If the amount exceeds 1000 ppm by weight, polymerization of the esterified product becomes difficult.

The anti-gelling solution containing a polymerization inhibitor is usually used in the form of a solution (also referred to as a polymerization inhibitor solution) in which the polymerization inhibitor is dissolved (or mixed) in an appropriate solvent. In addition to the agent solution, a part of the condensate can be used, and other additives may be included. The solvent for the polymerization inhibitor solution is preferably a solvent capable of acting as a dehydrating solvent in the reaction tank, and particularly preferably a solvent of the same type as the dehydrating solvent.

When the gelling inhibitor containing the polymerization inhibitor is allowed to act in the form of the above-mentioned polymerization inhibitor solution, the polymerization inhibitor must always be present and supplied so as to function effectively. 0.0 parts by weight of polymerization inhibitor
The range is from 0.01 to 10 parts by weight, preferably from 0.01 to 5 parts by weight.

When a polymerization inhibitor solution and a part of a condensate (preferably a condensate residue) are used in combination as a gelling inhibitor, the amount of the polymerization inhibitor solution is reduced and a sufficient amount is used instead. And a sufficient amount of the anti-gelling agent solution is preferably used. For this purpose, the flow rate per minute of the polymerization inhibitor solution per 1 m of the diameter (inner diameter) of at least a part of the overhead line and / or the condenser is 0.01 to 40 l / min m, preferably 0.1 to 40 l / min.
1 to 15 liters / minute m, more preferably 0.1 to 5 liters / minute m, and the condensate (at the reaction tank side of the overhead line on the reaction tank side of at least a part of the overhead line and / or 1 m of the diameter (inner diameter) of the condenser). When acting on the base portion, the flow rate of a part of the condensed residue) per minute is 1 to 1000 l / min m, preferably 5 to 500 l / min m, more preferably 10 l / min.
~ 200 l / min m. When the flow rate of the polymerization inhibitor solution is less than 0.01 liter / minute m, it is difficult to always exert sufficient polymerization inhibition ability, and when it exceeds 40 liter / minute m, the amount of the solvent increases. If the flow rate of a part of the condensate (or condensate residue) is less than 1 liter / minute m,
There is a possibility that a large amount of a gel-like substance may be generated. If the amount exceeds 1000 liter / min, no further effect can be obtained, which is uneconomical. The mixing ratio of the polymerization inhibitor solution and a part of the condensate (or condensate) is 0.5 to 1 part by weight of the polymerization inhibitor solution.
10,000 parts by weight, preferably 1 to 1000 parts by weight, more preferably 10 to 1000 parts by weight, particularly preferably 1 to 1000 parts by weight.
It is in the range of 0 to 100 parts by weight. If the amount is less than 0.5 part by weight, the amount of the solvent increases. If the amount exceeds 10,000 parts by weight, it is difficult to stably mix the two.

The method of causing the above-mentioned gelling inhibitor solution to act is not particularly limited as long as it can effectively act on the distillate, especially on the distilled low-boiling raw material. It can be performed by appropriately using a conventionally known method (means). The condensed region of the preferably gaseous distillate, specifically at least part of the overhead line and / or the base of the overhead line on the reactor side, also on the condenser side, so as to work effectively It is desirable that the anti-gelling agent solution can be effectively acted on the base portion of the gas, at the gas inlet near the top of the condenser. As a specific example, a nozzle is installed at the base of the reaction tank side in the overhead line, and the anti-gelling agent solution is sprayed, blown out, sprayed, discharged, blown up, and lowered here. To keep the inner wall of the base of the overhead line at the base of the reaction tank always wet, by installing a nozzle in the overhead line just before the condenser and spraying the gelling agent solution here A method of keeping the inner wall of the condenser always wet by passing it through the wall of the overhead line and reaching the inside of the condenser, etc., 'The tower of the condenser from the nozzle installed upward at the center of the top of the condenser tower Method to keep the inner wall of the condenser always wet by spraying an anti-gelling agent solution on the inner wall of the gas inlet at the top Including but not limited to.

When the polymerization inhibitor solution and a part of the condensate (or condensate) are used in combination, the method of refluxing a part of the condensate (or condensate) is not particularly limited. Instead, it can be performed by appropriately using a conventionally known method (means). For example, in the case where (i) a dehydration solvent is used for the esterification reaction and the dehydration solvent is distilled and refluxed, a part of the condensed residual liquid is withdrawn when returning the condensed liquid to the reaction tank, and The solution may be directly supplied to the nozzle portion to form a gelling inhibitor solution, or may be mixed with a polymerization inhibitor solution to form a gelling inhibitor solution during the supply to the nozzle portion. As a specific example, a storage section (tank or the like) for temporarily storing the condensed residual liquid is provided on the path for returning the condensed residual liquid to the reaction tank as necessary, and a part of the condensed residual liquid is provided from the storage section. , And a part of the condensed residual liquid extracted into the supply path of the polymerization inhibitor solution is joined to form a mixed anti-gelling agent solution simply. Here, as an advantage of providing the storage unit, the adjustment is convenient even when the amount of the condensed residual liquid for the anti-gelling agent solution to be withdrawn is increased to a fixed amount or gradually, and the condensed residual liquid to be returned to the reaction tank is convenient. The point is that the amount can be easily adjusted to be refluxed from the start to the end of the reaction while keeping the amount constant or the increase amount as small as possible. In addition, even if a storage unit such as a storage tank is not newly provided, for example, in a water separator,
The condensed liquid condensed and liquefied by the condenser is stored in one chamber and separated into two layers, an aqueous phase and a solvent phase. The lower aqueous phase is sequentially drained from the lower part of this chamber through piping, and the upper solvent phase is removed. The partition plate overflows and is stored in the other adjacent chamber. If the size of the chamber in which only the solvent phase is stored is increased, the water separator itself can also serve as a storage unit. However, the storage unit is not always necessary. When compared with the conventional polymerization inhibitor solution alone, for example,
Because the anti-gelling solution containing condensed residue is used,
The amount of the polymerization inhibitor solution can exhibit a large gelation preventing effect with the same or a smaller amount as in the prior art. For this reason, the increase in the amount of the solvent in the reaction tank is suppressed to the same level as or less than the conventional level. In particular, when the esterification time is short, the reaction temperature is hardly lowered and the influence on the reaction completion time is small, so that it is economically advantageous not to provide a storage unit. In addition, when the amount of the solvent returned into the reaction tank increases and increases, the solvent may be extracted out of the system without returning the solvent partially to the reaction tank. Also in this case, the amount of the solvent withdrawn outside the system is not large and the processing cost is small, so that it is more economically advantageous than providing the storage unit, and does not affect the performance of the product. Thus, it can be said that it is important to appropriately determine whether to provide a storage unit in consideration of the effect on performance and the cost effectiveness. When (ii) the esterification reaction is carried out without using a dehydrating solvent, the distillate is essentially only reaction water (including a slightly low-boiling-point raw material), and the distillate is placed in the reaction tank. Parts are not refluxed. Therefore, the whole or a part of the condensed residue obtained by separating and removing the reaction water (including the low-boiling-point raw material) from the condensate after the reaction of the gelling agent solution with the distillate is withdrawn, and the above-mentioned nozzle portion The solution may be directly supplied to the nozzle portion to form a gelling inhibitor solution, or may be mixed with a polymerization inhibitor solution during the supply to the nozzle portion to form a gelling inhibitor solution.
When a part of the condensed residual liquid is used, the remaining condensed residual liquid may be extracted outside the system. Note that the above-described method of causing the above-described method and the method of refluxing are merely representative examples, and the present invention is not limited thereto.

The means for preventing the generation of the gel derived from the distillate of the above (b) is at least a part of the overhead line, preferably a part not using the means for causing the gelling inhibitor to act. It heats and / or keeps at least 25%, more preferably at least 50%, even more preferably at least 75%. The portion to be heated and / or kept warm may be at least a part of the overhead line, and need not be continuous, but may be discontinuous. As a result, generation of a gel-like substance in the overhead line can be effectively and always prevented, and a high-quality esullated substance can be efficiently produced at low cost.

In the heating and / or heat retaining portion of the overhead line, the gaseous distillate comes into contact with the low temperature portion (specifically, the inner wall surface of the overhead line) to condense and liquefy to form a gel-like material. Therefore, the low-temperature portion was heated and / or heated so that the distillate did not condense and liquefy.
Alternatively, the temperature may be maintained by heating and / or maintaining the temperature so that the temperature of the distillate in the overhead line is equal to or higher than the azeotropic temperature. The azeotropic temperature varies depending not only on the type of dehydrating solvent but also on the ratio of reaction water / azeotropic solvent (changes at the beginning and end of the reaction), the degree of reduced pressure, and the like. Therefore, it is difficult to specifically indicate the temperature of the distillate by a numeral, but it is preferably heated to 25 to 200 ° C., more preferably 50 to 150 ° C., and particularly preferably 60 to 100 ° C. to obtain a temperature range. It is desirable to keep it warm. If the temperature of the distillate in the overhead line is lower than the azeotropic temperature, a large amount of gel-like substances will be generated in one year, which is not preferable. Further, when the temperature of the distillate in the overhead line is lower than 25 ° C., it is not preferable because generation of a gel-like substance is partially observed. If the temperature exceeds 200 ° C., no further effect corresponding to the temperature cannot be expected, which is uneconomical, and is not preferable because some of the distillate may be polymerized.

The change in the temperature of the distillate in the overhead line (particularly, the portion to be heated and / or kept warm) may be measured over time and controlled and controlled, but the temperature or heat of the wall of the overhead line may be controlled. There is an advantage that the temperature of the medium is relatively easy to measure and control and management are easy to perform. The temperature of the wall changes not only due to the difference in heat transfer characteristics due to the material and thickness of the wall, but also due to the difference in heating and / or heat retaining means (heat transfer wire, heat medium, etc.). For this reason, it is difficult to specifically indicate the temperature of the wall by a numeral, but it is preferably 25 to 400 ° C., and more preferably 50 to
The heating and / or the heating may be carried out so as to be in a range of from 300 to 300C, particularly preferably from 60 to 200C. If the temperature of the wall of the overhead line or the temperature of the heating medium is lower than 25 ° C., a large amount of gel-like substances will be generated in one year, which is not preferable. If the temperature exceeds 400 ° C., further effects corresponding to the temperature cannot be expected, which is uneconomical, and is not preferable because some distillate may be polymerized. In addition, the temperature of the distillate in the overhead line may vary as long as it is within the above-defined temperature range. Similarly, the temperature of the wall of the overhead line may be different depending on the portion of the overhead line. That is, the heating and / or heat retaining portion may be at least a part, and need not be continuous but may be discontinuous.

The term “heating and / or keeping the temperature” as used herein means that when heating is performed using a suitable heating means,
In the case where heating and heat retention are performed using an appropriate heating means and heat retaining means, this refers to the case where heat is retained using an appropriate heat retaining means.
Then, the temperature of the distillate and the temperature of the wall of the overhead line defined above are heated and / or heated so that the temperature does not deviate from the temperature range defined above while detecting a temperature change over time with a temperature sensor or the like. What is necessary is just to adjust using the heat retention means, the specific method is that it comprises a double tube (double tube) that can control the temperature of the distillate and the temperature of the wall of the inner tube through a medium that communicates with the outer tube, While appropriately controlling the temperature and flow rate of a medium (steam, pressurized steam, oil, heated gas such as combustion exhaust gas, etc.) passing through the outer tube, the distillate passing through the overhead line is passed through the medium through the outer tube while appropriately adjusting the temperature and the flow rate. A method of heating and / or keeping the temperature above the azeotropic temperature so as not to condense and liquefy, and fluctuate the amount of current to a heater such as an external heating wire (copper wire, etc.) coil or turn on / off the power. Heating and / or methods of insulation to be maintained at a predetermined set temperature by causing,
'A method in which the outer peripheral portion is covered with a member having high heat insulation (heat insulation) such as glass wool or foamed urethane so as to keep the temperature within the above-defined temperature range, and the like. Further, the above means may be combined for application.

(II) Partial Neutralization Step After the esterification reaction, the step of distilling off the dehydrating solvent by azeotropy with water, or the step of preparing an aqueous esterification solution for further polymerization using the esterified product, Hydrolysis by the acid catalyst occurs, resulting in deterioration of the quality and performance of the esterified product, and the product generated by the hydrolysis remains in the esterified product, and various dispersants such as cement dispersants and the like are increased by using the esterified product. In the case of synthesizing a polymer used for a tackifier or the like, quality and performance are deteriorated. In order to solve such a problem, it has been found that it is desirable to neutralize the acid catalyst with an alkali at 90 ° C. or lower after completion of the esterification reaction in the esterification step (I). This makes it possible to obtain a high-purity and high-quality esterified product without producing a hydrolysis product in the treatment process after the esterification reaction.

(III) Solvent Evaporation Step In the present invention, since the esterification reaction is carried out in a dehydrated solvent, after the esterification step (I) is completed, the acid catalyst is removed by the partial neutralization step (II). Further, a part of (meth) acrylic acid is neutralized, and then the dehydrating solvent is distilled off from the reaction solution.

According to a preferred embodiment of the solvent distillation step,
This will be described below.

When distilling off the dehydrating solvent from the reaction solution, 1000 ppm by weight or less, preferably 500 ppm by weight, based on the total amount of the starting alcohol and (meth) acrylic acid used.
Hereinafter, it has been found that the addition of a water-soluble polymerization inhibitor of 300 ppm by weight or less to the reaction solution, particularly preferably without addition, can prevent the generation of a high molecular weight product. . Since the water-soluble polymerization inhibitor added for the purpose of inhibiting the polymerization has a weak but active polymerization activity, unexpectedly, unreacted raw materials and polymerization of the esterified product, which is a product, are caused. And found that the polymerization inhibitor added during the esterification reaction effectively functions also when the dehydrating solvent is distilled off.

When a partial neutralization treatment is performed using a low-concentration alkaline aqueous solution, a relatively large amount of water is present in the reaction solution. In this case, since unreacted raw materials and esterified products may be dissolved in water and polymerized, from the viewpoint of preventing this, a water-soluble polymerization inhibitor is added to the reaction solution, and then the temperature is raised to the temperature specified below, and dehydration is performed. It is desirable to distill off the solvent by azeotropic distillation with water. However, 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 range is limited to the range where the polymerization inhibition ability can be exhibited more effectively than the polymerization activity (the range specified above). Need to be kept.

Here, the water-soluble polymerization inhibitor that can be used is not particularly limited, and examples thereof include hydroquinone, methoquinone, catechol and derivatives thereof (for example, pt-butyl catechol, etc.),
Hydroquinone monomethyl ether and the like may be mentioned, and one kind or a mixture of two or more kinds may be used. Of these, hydroquinone and methoquinone are preferred because they have relatively low polymerization activity.

The alkoxypolyalkylene glycol mono (meth) acrylate applicable to the raw material monomer of the cement dispersant obtained by the production method of the present invention is:
For example, JP-B-59-18338, JP-A-9-8
A (meth) acrylic acid (salt) and, if necessary, a monomer copolymerizable with these monomers in the same manner as known methods such as the method described in JP-A-6990 and JP-A-9-286645. Together with the polymerization reaction,
It can be used as a main component of a high-performance cement dispersant having excellent cement dispersing ability.

[0076]

The present invention will be described more specifically with reference to the following examples.

Example 1 Methoxypoly (n = 25) ethylene glycol 16500 k was added to a reaction vessel (volume 34 m ³ ) equipped with a thermometer, a stirrer, a water separator and a condenser (heat transfer area 163 m ² ).
g, 4740 kg of methacrylic acid, 235 kg of paratoluenesulfonic acid monohydrate, 5 kg of phenothiazine, and 1060 kg of cyclohexane.
The esterification reaction was performed at 30 ° C. and a reaction temperature of 115 ° C.
At this time, the heat transfer area of the condenser / the volume of the reaction tank = 4.
8 (m ^-1 ).

It was confirmed that the esterification rate reached 99% in about 20 hours.

Table 1 below shows the reaction composition, esterification conditions, reaction vessel volume, heat transfer area of the condenser, and the ratio thereof (heat transfer area of the condenser / volume of the reaction vessel) in this example.

Example 2 8250 kg of methoxypoly (n = 25) ethylene glycol was placed in a reactor (volume: 17 m ³ ) equipped with a thermometer, a stirrer, a water separator and a condenser (heat transfer area: 101 m ² ).
Methacrylic acid 2370 kg, paratoluenesulfonic acid 1
118 kg of hydrate, 2.5 kg of phenothiazine and 530 kg of cyclohexane were charged and the jacket temperature was 13
The esterification reaction was performed at 0 ° C. and a reaction temperature of 115 ° C. At this time, the heat transfer area of the condenser / the volume of the reaction tank = 5.9
(M ^-1 ).

It was confirmed that the esterification rate reached 99% in about 20 hours.

The reaction composition, esterification conditions, reaction vessel volume, heat transfer area of the condenser and the ratio thereof (heat transfer area of the condenser / volume of the reaction vessel) of this example are shown in Table 1 below.

Example 3 3150 kg of methoxypoly (n = 25) ethylene glycol, 905 kg of methacrylic acid were placed in a reactor (volume 6.5 m ³ ) equipped with a thermometer, a stirrer, a water separator and a condenser (heat transfer area 30 m ² ). 202 kg of paratoluenesulfonic acid monohydrate, 1 kg of phenothiazine and 202 kg of cyclohexane were charged, and an esterification reaction was performed at a jacket temperature of 130 ° C and a reaction temperature of 115 ° C. At this time, the heat transfer area of the condenser / the volume of the reaction tank = 4.6 (m ⁻¹ ).

It was confirmed that the esterification rate reached 99% in about 20 hours.

The reaction composition, esterification conditions, reaction vessel volume, heat transfer area of the condenser and the ratio thereof (heat transfer area of the condenser / volume of the reaction vessel) of this example are shown in Table 1 below.

[0086]

[Table 1]

As shown in the above Examples 1 to 3, after a condenser is newly provided between the reaction tank and the water separator, the distillation is performed from the reaction tank with respect to the volume of the reaction tank for performing the esterification reaction. If the ratio of the heat transfer area of the condenser for condensing and liquefying the distillate containing the reaction product water is within the range specified in the present invention, a large-scale reactor that can be industrially used is used to stably perform high performance. It was confirmed that an alkoxypolyalkylene glycol mono (meth) acrylate applicable to a raw material monomer of a suitable cement dispersant can be mass-produced.

[0088]

According to the present invention, after a new condenser is provided between the reaction tank and the water separator, the amount of reaction product water distilled from the reaction tank relative to the volume of the reaction tank for performing the esterification reaction is included. The ratio of the condenser for condensing and liquefying the distillate was 1.
By setting the content within the range of 0 to 20 m ⁻¹ , it is possible to continuously mass-produce alkoxypolyalkylene glycol mono (meth) acrylate applicable to the raw material monomer of the high-performance cement dispersant. With benefits. That is, it is possible to provide a large-scale apparatus that is excellent in industrial use (including productivity and economy). By satisfying the above requirements, the distillate can be completely condensed in the condenser before the gaseous distillate enters the water separator. As a result, it is possible to solve the above-mentioned problem that has occurred when the scale of the laboratory configuration is increased. That is, since the gaseous distillate is completely condensed by the condenser before entering the water separator, the distillation speed is stabilized without causing a pressure increase, and the reaction time can be prevented from being prolonged. Similarly,
Since the inside of the water separator is not pressurized, the performance of the water separator is fully exhibited and the water and the solvent can be separated properly, and there is no risk of destruction or damage without using a pressure-resistant member. . In addition, since high-temperature gaseous distillate does not enter the water separator, the members are not exposed to high temperatures and degrade or break due to the accumulation of thermal fatigue without using heat-resistant members. Never even.

In the present invention, by providing a mechanism and / or means for preventing generation of a gel-like substance derived from a distillate, adhesion and deposition of the gel-like substance in continuous mass production are performed. This makes it possible to apply alkoxypolyalkylene glycol mono (meth) acrylic acid as a raw material monomer for a high-performance cement dispersant without blocking the distilling path and preventing total condensation due to a decrease in heat exchange efficiency. The ester can be operated stably for a long period of time and can be maintenance-free for a long period of time.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-9-328346 (JP, A) JP-A-2003-64137 (JP, A) JP-A-2000-212273 (JP, A) JP-A-2000-302729 (JP, A) , A) JP-A-10-236859 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 65/329-65/337

Claims (4)

(57) [Claims] A ratio of a heat transfer area of a condenser for condensing and liquefying a distillate containing reaction product water distilled from the reaction tank to a volume of the reaction tank for performing the esterification reaction is 3.5.
An apparatus for producing an alkoxypolyalkylene glycol mono (meth) acrylate applicable to a raw material monomer of a cement dispersant, which is in a range of from 7.0 m ^-1 . 2. The volume of a reaction tank for performing an esterification reaction is
Distillate containing reaction product water distilled from the reaction vessel
The ratio of the heat transfer area of the condenser to be condensed and liquefied is 4.5.
セ 6.0 m ⁻¹ , characterized by being within the range of
Alkoxy polyal applicable to the raw material monomer of the dispersant
Made of kylene glycol mono (meth) acrylate
Manufacturing equipment. 3. A manufacturing apparatus according to claim 1 or 2 mechanism and / or means for preventing the occurrence of gels derived from the distillate, characterized by comprising further provided. 4. By using the manufacturing apparatus according to any one of claims 1 to 3, the general formula _{^{R 1 O (R 2 O)}} n H ( In the formula, ^{R 1} is 1 to 30 carbon atoms Represents a hydrocarbon group,
R ² O represents an oxyalkylene group having 2 to 18 carbon atoms, wherein the repeating units of each R ² O may be the same or different, and R ² O is a mixture of two or more kinds. In the case of the form, the repeating unit of each R ² O may be added in a block shape or in a random shape, and n represents the average number of moles of the oxyalkylene group added; The number is 300. )
Production of an alkoxypolyalkylene glycol mono (meth) acrylate applicable to a raw material monomer of a cement dispersant, characterized by conducting an esterification reaction between an alkoxypolyalkylene glycol and (meth) acrylic acid represented by Method.