JP3537687B2 - Method for producing esterified product and method for producing polymer using esterified product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an esterified product and a method for producing a polymer using the esterified product. More specifically, when an esterified product obtained by performing an esterification reaction between alcohol and (meth) acrylic acid in a dehydrated solvent, and a polymer obtained by using the esterified product as a monomer component, these are used. The present invention relates to a method for producing an esterified product and a method for producing a polymer using the esterified product in order to obtain an esterified product and a polymer thereof which do not cause problems in handling such as odor.

[0002]

2. Description of the Related Art Polymer components used in cement dispersants, pigment dispersants such as calcium carbonate, carbon black and ink, scale inhibitors, dispersants for gypsum / water slurries, dispersants for CWM, thickeners, etc. Is the alcohol and (meth)
Various (meth) acrylic esters (simply referred to as esterified products in the present specification) obtained by subjecting acrylic acid to an esterification reaction are used as a monomer component, and are obtained by a polymerization reaction. . In such an esterification reaction, reaction product water is simultaneously produced as a by-product, and unless this reaction product water is removed from the reaction system (that is, the reaction product water accumulates), the reaction proceeds in the direction of producing an esterified product due to an equilibrium reaction. Stuck. Therefore, in order to synthesize an esterified product, a dehydrating solvent is used, and the reaction product water is distilled off (azeotropic). Among them, the reaction product water is separated and removed, and the reaction is carried out by refluxing the dehydration solvent. After completion of the reaction, the dehydrated solvent is distilled off to obtain the desired esterified product. Then, a polymerization reaction is carried out using the obtained esterified product as a monomer component to produce a target polymer component.

As such a production method, for example, Japanese Patent Application Laid-Open No. 9-328346 describes a method for producing an esterified product in Comparative Examples 1 and 2, and Comparative Examples 3 and 4 describe a method for producing a polymer using the esterified product. It describes an example of manufacturing and using this as a cement dispersant. According to the publication, first, as a method for producing an esterified product, a reactor (separable flask) is provided with a thermometer, a stirrer, and a water separator, and methacrylic acid is used as a raw material in a reaction apparatus capable of separating reaction product water. And methoxypolyethylene glycol (average number of moles of added oxyethylene group: 10 mol), sulfuric acid (Comparative Example 1) or paratoluenesulfonic acid (Comparative Example 2) as an acid catalyst, phenothiazine as a polymerization inhibitor, and cyclohexane as a dehydrating solvent. The mixture was heated with stirring to distill off the cyclohexane-water azeotrope under normal pressure, refluxed cyclohexane while removing the reaction water with a water separator, and carried out an esterification reaction. Is described, and a method of synthesizing a desired esterified product is described. Next, as a method for producing a polymer using the esterified product, 195 g of water was charged into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser, and the inside of the reactor was stirred. The atmosphere was replaced with nitrogen, heated to 95 ° C. under a nitrogen atmosphere, and then a monomer aqueous solution obtained by mixing the esterified product, methacrylic acid and water obtained in Comparative Example 1 or 2, and a 1.5% aqueous ammonium persulfate solution were added. After dropwise addition for 4 hours, 1.5% ammonium persulfate was further added dropwise for 1 hour after completion of the addition, and then the temperature was maintained at 95 ° C. for 1 hour to complete the polymerization reaction. A method for obtaining (a cement dispersant) is described.

[0004] However, as disclosed in the above-mentioned publication, in the esterification reaction using a dehydrating solvent, except for distilling off the dehydrating solvent after completion of the reaction, there are technical problems in distilling off the dehydrating solvent. As of now, there has been no report on this. Further, when a polymerization reaction is carried out using the esterified product as a monomer component, it is not pointed out that there is no particular problem with respect to the influence of the dehydrated solvent on the obtained polymer. There is no report at this time.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies on a method for producing an esterified product using a dehydrating solvent, and a method for producing a polymer which can be used for various applications using the esterified product. In the process of (1), even if the dehydration solvent is sufficiently distilled off after the esterification reaction, the dehydration solvent dissolved in the reaction solution remains, and the reaction aqueous solution becomes cloudy. For example, when taking out of the reaction system for storage or transportation, when performing work while opening to the atmosphere, the dehydrated solvent remaining in the reaction solution is vaporized (slow release), resulting in strong solvent odor. It has been found that there is a problem that the working environment of the handling worker deteriorates. (2) Furthermore, even after producing a polymer that can be used for various applications using the obtained esterified product, the dehydration solvent used during the esterification reaction remains in the polymerization reaction solution, and the polymerization reaction solution Remains cloudy,
For example, such a polymer as a cement dispersant or the like, usually,
When used in applications handled in a natural environment, the dehydrated solvent vaporizes (slowly releases) and emits a strong solvent odor. It has also been found that there is a problem that the working environment of workers who handle the cement composition at construction sites and the like deteriorates.

Accordingly, an object of the present invention is to provide an esterified product obtained by performing an esterification reaction between an alcohol and (meth) acrylic acid in a dehydrated solvent, and a polymer obtained by using the esterified product as a monomer component. Provided is a method for producing an esterified product and a method for producing a polymer using the esterified product, in order to obtain an esterified product and a polymer thereof which do not cause a handling problem due to a solvent smell when using them. Things.

[0007]

Means for Solving the Problems Accordingly, the present inventors have:
In order to solve the above problems, a method for producing an esterified product and a method for producing a polymer using the esterified product,
As a result of intensive studies, the dehydration solvent slightly remaining in the reaction aqueous solution after the esterification reaction between alcohol and (meth) acrylic acid was removed from the reaction aqueous solution or an ester obtained by performing the esterification reaction on the reaction aqueous solution. A gas-liquid contact with an inert gas during the polymerization reaction using the compound as a monomer component or from the polymerization reaction solution after polymerization, to drive out the dehydrating solvent dissolved in the solution extremely efficiently The present inventors have found that it is possible to solve the problem and found that the problem of bad smell due to solvent odor when handling them can be solved, and completed the present invention based on the knowledge.

That is, the object of the present invention is to provide the following (1) to
This can be achieved by the method described in (8).

(1) In a dehydrating solvent, a compound represented by the general formula (1)

[0010]

Embedded image

(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 The repeating units of each R ² O may be the same or different, and when R ² O is in the form of a mixture of two or more types, the repeating units of each R ² O may be added in block form or added in random form. N represents the average number of moles of the oxyalkylene group added, and 0 to 3
The esterification reaction between an alcohol represented by the formula (00) and (meth) acrylic acid is performed, and after the esterification reaction is completed, when or after the dehydrating solvent is distilled off from the reaction solution,
More than 10% by volume of the volume of the reactor with respect to the reaction solution
A method for producing an esterified product, which comprises contacting an amount of an inert gas.

(2) An inert gas in an amount exceeding 10% by volume of the volume of the reactor is added to the reaction solution for more than 10 minutes.
The method for producing an esterified product according to the above (1), wherein the method is contacted for a period of time .

(3) The dehydrating solvent is 1% of the capacity of the reactor.
(1) or the above (1), wherein the contact of the inert gas with the reaction liquid is started at the stage when the volume becomes equal to or less than the volume%.
The method for producing an esterified product according to (2) .

(4) Any one of the above (1) to (3), wherein the reaction solution is brought into contact with the reaction solution by blowing a nitrogen gas in a temperature range of 90 to 100 ° C. A method for producing an esterified product according to one of the above.

[0015]

[0016]

(5) Production according to ( 1) to (4) above
The esterified product obtained by the method as a monomer component,
A method for producing a polymer using an esterified monomer, wherein an inert gas is brought into contact with the polymerization reaction solution during or after the polymerization reaction.

(6) The method for producing a polymer according to the above (5), wherein an amount of an inert gas exceeding 10% by volume of the polymerization reactor is brought into contact with the polymerization reaction solution. .

(7) When the amount of the solvent in the reactor becomes 1% by volume or less of the volume of the polymerization reactor, contact of the polymerization reaction solution with an inert gas is started. The method for producing a polymer according to 5).

[0020]

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described by dividing into a method for producing an esterified product and a method for producing a polymer using the esterified product.

First, the process for producing an esterified product according to the present invention is carried out in a dehydrating solvent by the general formula (1)

[0023]

Embedded image

(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 The repeating units of each R ² O may be the same or different, and when R ² O is in the form of a mixture of two or more types, the repeating units of each R ² O may be added in the form of a block or randomly. And n represents an average number of moles of the oxyalkylene group added, and 0 to 3
The esterification reaction between an alcohol represented by the formula (00) and (meth) acrylic acid is performed, and after the esterification reaction is completed, when or after the dehydrating solvent is distilled off from the reaction solution,
An inert gas is brought into contact with the reaction solution. This can solve the problem of malodor due to solvent odor when handling these.

Hereinafter, preferred embodiments of the method for producing an esterified product of the present invention will be described step by step.

The method for producing the esterified product of the present invention is as described above. In particular, in the present invention, the alcohol represented by the general formula (1) is prepared in a dehydrating solvent in the presence of an acid catalyst and a polymerization inhibitor. (Hereinafter, also simply referred to as “alcohol”) and (meth) acrylic acid are subjected to an esterification reaction (esterification step), and after the esterification reaction is completed, the acid catalyst or all of the acid catalyst and one of (meth) acrylic acid It is desirable to neutralize the part (partial neutralization step) and then contact the reaction liquid with an inert gas when or after distilling off the dehydrated solvent from the reaction liquid (solvent removal step).

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

First, an alcohol of the general formula (1), (meth) acrylic acid, a dehydrating solvent, an acid catalyst, and a polymerization inhibitor as raw materials are charged into a reaction system (reaction tank). The esterification reaction is performed until the esterification ratio is reached.

The alcohol raw material that can be used in the above ester reaction is a compound represented by the following general formula (1).

[0030]

Embedded image

In the general formula (1), R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms. When R ¹ is a hydrocarbon group having more than 30 carbon atoms, an esterified product of the compound of the general formula (1) and (meth) acrylic acid is obtained by, for example, copolymerizing with (meth) acrylic acid. The water solubility of the resulting copolymer is reduced, and the application performance, for example, the cement dispersing performance, is reduced. The preferred range of R ¹ varies depending on the intended use. For example, when used as a raw material for a cement dispersant, R ¹ has ¹ carbon atom.
Preferred are straight-chain or branched-chain alkyl groups and aryl groups of from 18 to 18. Specific 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, Alkyl groups such as ethylhexyl group, decyl group, dodecyl group, undecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, heneicosyl group, docosyl group; and phenyl group. An aryl group; an alkylphenyl group such as a benzyl group or a nonylphenyl group; a cycloalkyl group such as a cyclohexyl group; an alkenyl group;
Alkynyl group and the like. Among these, when used as a raw material for a cement dispersant, as described above, a methyl group, an ethyl group, a propyl group, a butyl group, and a phenyl group are preferred.

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 compound of the general formula (1) and (meth) acrylic acid is copolymerized with, for example, (meth) acrylic acid. The water solubility of the resulting copolymer is reduced,
The application performance, for example, the cement dispersing performance and the like is reduced. 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. Further, the repeating units of R ² O may be the same or different. When the repeating units of R ² O are different, that is, when two or more different repeating units are present, the repeating units of each R ² O may be added in a block shape or in a random shape. May be.

Further, n is a number from 0 to 300, and R ²
It represents the average number of moles of the repeating unit of O (oxyalkylene group). When n exceeds 300, the polymerizability of the esterified product of the compound of the general formula (1) and (meth) acrylic acid decreases. The 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 5 to 200, more preferably 8
１５０150. When used as a thickener or the like, the average number of added moles n is preferably a number of 10 to 250, and more preferably 50 to 200. Also, n = 0
In the case of the above, R ¹ is preferably a hydrocarbon group having 4 or more carbon atoms from the viewpoint of solubility in water and the boiling point. That is, when n = 0 in the general formula (1), particularly alcohols such as methanol and ethanol have a low boiling point and evaporate together with the generated water, and further dissolve in the generated water, so that a part of the alcohol raw material goes out of the system. This is because it is distilled off and the yield of the desired esterified compound is reduced.

As the alcohol raw material represented by the general formula (1), one kind may be used alone, or two or more kinds may be used as a mixture. The form of use of a mixture of two or more alcohol raw materials represented by the general formula (1) is not particularly limited, and a mixture of two or more types in which at least one of R ¹ , R ² O or n is different In the case where R ¹ is composed of two types, a methyl group and a butyl group, R ² O
Is composed of two types, an oxyethylene group and an oxypropylene group, when n is 1 to 10 and 11 to 100
In the case of being composed of two types, those which are appropriately combined with and the like.

With respect to the (meth) acrylic acid that can be used in the above ester reaction, acrylic acid and methacrylic acid may be used alone or in combination. Any range can be employed.

The mixing ratio of the raw materials used in the esterification reaction is stoichiometrically 1: 1 (molar ratio).
In practice, there is no particular limitation as long as the esterification reaction between the alcohol and (meth) acrylic acid proceeds efficiently, but usually, one of the raw materials is used in excess to accelerate the esterification reaction. In addition, from the viewpoint of purification of the target esterified product, an excessive amount of a raw material having a lower boiling point which is easily distilled off is used. Further, in the present invention, when azeotropic distillation of the reaction water and the dehydrating solvent during the esterification reaction, a part of the low-boiling point (meth) acrylic acid is also distilled off and taken out of the reaction system. (Meta) for quantity (prepared quantity)
It is preferable to add the used amount (prepared amount) of acrylic acid 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 mol, per mol of alcohol.
10 to 10 mol. If the amount of the (meth) acrylic acid is less than 1.0 mol based on 1 mol of the alcohol, the esterification reaction does not proceed smoothly, and the yield of the desired esterified product is insufficient. If it exceeds 30 moles, no improvement in yield corresponding to the addition is observed, which is uneconomical and is not preferred.

In the esterification reaction of the present invention, it is desirable to carry out the reaction in the presence of an acid catalyst. By performing the reaction in the presence of an acid catalyst, the reaction can proceed quickly. Acid catalysts that can be used in the esterification reaction of the present invention include, for example, sulfuric acid, methanesulfonic acid, paratoluenesulfonic acid, paratoluenesulfonic acid hydrate, xylenesulfonic acid, xylenesulfonic acid hydrate, naphthalene Sulfonic acid, naphthalenesulfonic acid hydrate, trifluoromethanesulfonic acid, “Naf
ion "resin," Amberlyst 15 "resin, phosphotungstic acid, phosphotungstic acid hydrate,
Examples thereof include hydrochloric acid, and among these, sulfuric acid, paratoluenesulfonic acid, paratoluenesulfonic acid hydrate, and methanesulfonic acid are preferably used. Furthermore, the present inventors have found that one of the causes of the formation of the impurity diester which causes the deterioration of the quality and performance of the esterified product is due to the cleavage of the alcohol raw material, and that the cleavage can also be caused by the acid catalyst. I learned. Based on such knowledge, it has been found that the acid catalyst which is hard to be cleaved is more desirable. Specific examples of the acid catalyst include paratoluenesulfonic acid and paratoluenesulfonic acid hydrate.

The amount of the acid catalyst to be used is not particularly limited as long as the desired catalytic action can be effectively exerted. As a solution to the technical problem in the esterification reaction in the presence of an acid catalyst that gives a high molecular weight crosslinked polymer having poor dispersing performance and thickening properties, the amount of the acid catalyst used is 0.4 meq / m g or less, preferably in the range of 0.36 to 0.01 meq / g, more preferably in the range of 0.32 to 0.05 meq / g, such a technical problem can be solved. Is found.

That is, when the amount of the acid catalyst used exceeds 0.4 meq / g, the amount of diester formed in the reaction system during the esterification reaction increases, and the esterified product obtained by the esterification reaction is used. Performance of the cement dispersant or the like synthesized by the process, for example, the cement dispersing ability and the like are reduced. Here, the amount of use of the acid catalyst (milli-equivalent / g) is calculated based on the number of equivalents of H ⁺ of the acid catalyst used in the reaction (milli-equivalent), and the total charge amount (g) of the raw material alcohol and (meth) acrylic acid. ). More specifically, it is a value calculated by the following equation.

[0040]

(Equation 1)

The above-mentioned acid catalyst may be added to the reaction system all at once, continuously or sequentially. However, from the viewpoint of workability, it is preferable to charge the reaction catalyst together with the raw materials in the reaction tank.

In the above esterification reaction, it is desirable to carry out the reaction in the presence of a polymerization inhibitor. By using a polymerization inhibitor, polymerization of the raw material alcohol and (meth) acrylic acid, the 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, dithiobenzoyl disulfide, cupperon, Copper (II) chloride and the like can be mentioned. Of these, phenothiazine, hydroquinone, and methoquinone are preferably used because of the solubility of the dehydrating solvent and generated water. These polymerization inhibitors are
They may be used alone or as a mixture of two or more.

The amount of the polymerization inhibitor used is 0.001 to 1% by weight, preferably 0.001 to 1% by weight based on the total charged amount of alcohol and (meth) acrylic acid as raw materials.
It is in the range of 0.1% by weight. When the amount of the polymerization inhibitor is less than 0.001% by weight, the polymerization inhibitory ability is not sufficiently exhibited, and the polymerization of alcohol, (meth) acrylic acid as a raw material, an esterified product as a product, or a mixture thereof is performed. When the amount of the polymerization inhibitor exceeds 1% by weight, the amount of the polymerization inhibitor remaining in the esterified product is increased.
It is not preferable in terms of quality and performance, and further effects corresponding to excessive addition cannot be obtained, which is not preferable from an economic viewpoint.

Further, in the esterification reaction of the present invention, the esterification reaction is carried out in a dehydrating solvent.
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. Examples of the dehydrating solvent include benzene, toluene, xylene, cyclohexane, dioxane, pentane, hexane, heptane, chlorobenzene, and isopropyl ether. Can be. Among them, the azeotropic temperature with water is 150 ° C or less, more preferably 60 to 90 ° C.
Are preferred, and specific examples 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 control of the temperature in the reaction system during the reaction and control of the condensation and liquefaction of the azeotrope).

It is desirable that the dehydrating solvent be refluxed while being azeotroped with the reaction water outside the reaction system, condensed and liquefied, and separated and removed from the reaction water. 1 to 100% by weight, preferably 2 to 100% by weight based on the total amount of alcohol and (meth) acrylic acid
〜50% by weight. When the amount of the dehydrating solvent used is less than 1% by weight, the reaction water generated during the esterification reaction cannot be sufficiently removed from the reaction system by azeotropic distillation, and the equilibrium reaction of the esterification does not easily proceed. Not
When the amount of the dehydrated solvent exceeds 100% by weight, the effect corresponding to the excessive addition cannot be obtained, and a large amount of heat is required to keep the reaction temperature constant. Absent.

It is desirable that the present inventors distill the reaction product water generated in the esterification reaction out of the reaction system, and act a polymerization inhibitor on the distillate containing the reaction product water. Is found. As a result, the polymerization reaction occurs at the stage of condensing and liquefying the low-boiling raw material distilled together with the reaction product water to form a gel-like substance which causes deterioration of product quality and blockage of equipment and the like. Can be prevented.

In the present invention, the esterification reaction can be performed either batchwise or continuously, but is preferably performed batchwise.

The reaction conditions for the esterification reaction may be any conditions under which the esterification reaction proceeds smoothly. For example, the reaction temperature is 30 to 140 ° C., preferably 6 to 140 ° C.
0 to 130 ° C, more preferably 90 to 125 ° C, particularly preferably 100 to 120 ° C.
This is a general (in a broad sense) condition of the esterification reaction of the present invention, in which the above-mentioned dehydrating solvent is azeotroped with the reaction product water outside the reaction system, and the reaction product water is condensed and liquefied, and is refluxed while being separated and removed. This is one example, and is included in these ranges, but does not completely match. ). If the reaction temperature is lower than 30 ° C., the reflux of the dehydrating solvent is slow and dehydration takes a long time, and the esterification reaction does not easily proceed, which is not preferable. On the other hand, when the reaction temperature exceeds 140 ° C., excessive amounts of diesters are generated by cutting the alcohol raw material, and in addition to the cement dispersing performance, the dispersing performance and the thickening property in various applications are reduced, and the raw material is polymerized. Also, the performance and quality of the esterified product, which is a product, are deteriorated, such as an increase in the amount of the raw material mixed into the azeotrope. The reaction time is such that the esterification rate is at least 70%, preferably at least 80%, as described later.
, But usually 1 to 50 hours, preferably 3 to 40 hours. 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.

[0050]

(Equation 2)

Esterification rate measurement conditions Analyzer: Waters Millennium chromatography manager Detector: Waters 410 RI detector Column used: GL Sciences Inertsyl ODS-2 3 columns Temperature: 40 ° C. Eluent: 8946 g of acetonitrile 6000 g acetic acid 54 g was 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 equation, 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 reached a specified value or more.

(II) Partial Neutralization Step Next, in the present invention, in the esterification step (I), when an ester reaction is carried out in the presence of an acid catalyst, the partial neutralization step described below is carried out. It is desirable to do. That is, the present inventors, when water is added in the step of distilling off the dehydrating solvent after the esterification reaction and azeotrope, or for further polymerization using an esterified product, after the esterification reaction, adjust water is added. When an aqueous solution of the produced esterified product is prepared, hydrolysis by an acid catalyst occurs to cause deterioration of the quality and performance of the esterified product, and also the product produced by the hydrolysis (hereinafter, also simply referred to as a hydrolysis product). Remains in the esterified product, when using the esterified product to synthesize a polymer used for various dispersants such as a cement dispersant or a thickener, the hydrolysis product is used for polymerization. Since the impurities become unrelated impurities, the polymerization rate (and thus the productivity) is reduced, and the quality and performance of the polymer are also deteriorated. Esterification After completion of the reaction by one in which an acid catalyst above 90 ℃ was found that it is desirable to neutralize with alkali. 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 reaction is carried out in the esterification step (I), the dehydration solvent is distilled from the reaction solution. To leave. When the esterification reaction is performed in the presence of an acid catalyst, the esterification reaction is performed in the esterification step (I), and then the acid catalyst is further processed in the partial neutralization step (II). Neutralizes some of the (meth) acrylic acid,
Next, the dehydrating solvent is distilled off from the reaction solution. At this time, an inert gas is brought into contact with the reaction solution.

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

In the solvent distilling step of the present invention, after the esterification reaction is completed (partial neutralization treatment is performed if necessary), when the dehydrating solvent is distilled off from the reaction solution, the solvent is not removed from the reaction solution. The present invention is characterized in that an active gas is brought into contact therewith, and is a feature of the present invention. As a result, the dehydrating solvent dissolved in the reaction solution can be expelled very efficiently by the inert gas, and the resulting esterified compound can be prevented from generating a solvent odor.

Here, the inert gas used is:
There is no particular limitation as long as it is inert to the components of the reaction solution. For example, a gas such as air, nitrogen gas, helium gas, argon gas, or carbon dioxide (preferably a gas containing no water vapor) And the like, but preferably, air and nitrogen gas from the viewpoint of economy. Also,
One of these inert gases may be used alone, or two or more of them may be used in combination. When the inert gas is brought into contact with the reaction solution during the esterification reaction or the polymerization reaction, the inert gas is heated to the same temperature as the solution temperature in advance by a suitable heating means so that the temperature of the reaction solution in the system does not fluctuate. It is preferable to supply the inert gas thus prepared.

The method for bringing the inert gas into contact with the reaction liquid is not particularly limited, and the inert gas may be flowed over the reaction liquid to make gas-liquid contact.
An inert gas may be blown into the reaction liquid to make gas-liquid contact. Above all, it is preferable to blow the inert gas into the reaction solution and bring it into gas-liquid contact because the contact efficiency is excellent. In particular, the bubbles of the inert gas are satisfactorily dispersed (in a state close to complete mixing uniformly) throughout the tank, and the contact area (gas-liquid interface area) and contact time are increased (contact efficiency is increased).
As described above, a predetermined flow rate of the inert gas is blown continuously or intermittently from the center of the bottom of the reaction tank, and the bubbles of the inert gas are divided into fine particles and the dispersed phase by an appropriate gas-liquid stirring device. A method in which the hold-up is increased, the contact area is increased, and gas-liquid contact is performed so as to reach the entire tank can be suitably used. That is, the reaction solution is stirred so that it can be brought into good gas-liquid contact with the inert gas. However, the gas-liquid mass transfer speed in such a stirring tank is mainly due to the contact interface area and the strength of liquid turbulence at the interface. Depends on. Since the strength of the liquid turbulence is contributed by the stirring power per unit volume of the liquid, in order to efficiently drive out the dehydrating solvent from the reaction liquid, regardless of the contact method, the contact area and the liquid at the interface are required. The optimum contact method may be appropriately determined according to the stirring tank and the stirring device used in consideration of the strength of the turbulence. In addition to the above, various conventionally known gas-liquid contact methods can be applied. For example, the top, side, and / or
Alternatively, an air nozzle or the like can be used to blow an inert gas into one or more of the bottom surface portion and further into the internal space of the reaction tank (for example, in the vicinity of the stirring blade) through a pipe or the like extending into the reaction tank. May be provided. In addition, the outlet portion may be one that only blows out the inert gas, and a plurality of pores are formed in the outlet portion, and by blowing through this,
A conventionally known gas-liquid contacting method can be applied, for example, the bubbles of the inert gas may be fragmented to some extent before stirring.

The amount of the inert gas used to drive off the remaining degreasing solvent depends on the contact method and the contact start time, but usually, the capacity of the reactor is larger than the reaction solution. In an amount exceeding 10% by volume, preferably 15 to 300% by volume, more preferably 20 to 200% by volume. When the amount of the inert gas used is 10% by volume or less of the capacity of the reactor, the dissolved dehydrating solvent cannot be driven out sufficiently, and the effect of removing the solvent odor is not sufficient. If the content exceeds 300% by volume, the intended purpose of driving out the dissolved dehydrated solvent is achieved, but the inert gas containing the dehydrated solvent recovered after gas-liquid contact is reused or discharged outside the system. Although it will be exhausted, in any case, it is necessary to separate and remove the dehydrating solvent from the inert gas.If a large amount of inert gas is used, the cost of the inert gas itself and the cost of its recovery are high. This is not preferred.

The relationship between the capacity of the reactor and the capacity of the reaction solution is that, in order to carry out the esterification reaction, it is necessary to maintain the reaction solution at a predetermined temperature, and that the reaction solution is filled to a certain extent from the viewpoint of reaction efficiency. It is desirable that, due to the progress of the reaction, part of the reaction product water is removed out of the system, an aqueous alkali solution is added in the partial neutralization treatment, or the volume of the reaction solution in the reactor fluctuates due to the removal of the dehydrating solvent. Therefore, it is inappropriate to unambiguously define the reaction volume, but the volume of the reaction solution at the start of the contact with the inert gas is approximately 30 to 90% of the volume of the reactor.
Range. This means that when an inert gas flows over the reaction surface of the reactor and comes into gas-liquid contact,
If there is an excessive volume of space above the surface of the reaction solution, the contact efficiency is poor and a large amount of inert gas needs to be ventilated. In addition, it is necessary to feed under pressure, and the inside of the tank may be pressurized. In the case where an inert gas is blown into the reaction solution in the reactor to make gas-liquid contact, the volume ratio of the reaction solution in the reactor does not matter.

The timing of starting contact of the reaction solution with an inert gas is such that after the esterification reaction is completed (partial neutralization is performed, if necessary), the dehydrating solvent is distilled off from the reaction solution. The contact of the inert gas may be started before the temperature is raised in accordance with the above, or conversely, after the temperature is raised and the dehydrating solvent is distilled off as described later, the contact of the inert gas is started separately. However, from the viewpoint of the efficiency of removing the dehydrated solvent, the operation of distilling off the dehydrated solvent can reduce the volume of the dehydrated solvent to 1% of the capacity of the reactor.
It is desirable to start contacting the reaction solution with an inert gas at the stage when the volume becomes equal to or lower than the volume%, preferably within the range of 0.1 to 0.9 volume%. The concentration of the dehydrated solvent remaining in the reactor (in the reaction solution) (% by volume based on the volume of the reactor)
Is a value measured from the gas chromatogram of the reaction solution.

The time and flow rate of contacting the reaction solution with the inert gas may be appropriately determined so that the time and flow rate of the inert gas fall within the range of the amount of the inert gas specified above. However, even if a large flow of inert gas is flown in a short time, the inert gas may not always be able to be efficiently expelled. It becomes difficult to disperse the active gas bubbles over the entire area of the tank in a state close to complete mixing, and the contact efficiency also deteriorates. In addition, since the contact time and the flow rate depend on the contact start timing and the temperature condition of the inert gas, it is inappropriate to univocally specify the contact time and the flow rate. The setting is not desirable, and the contact time is 20 to 300 minutes, preferably 3 minutes.
The volume ratio of the inert gas per unit time to the reactor volume is 0.02 to 0 to 180 minutes.
~ 9 / hour, more preferably 0.03-6 / hour. When the contact time is less than 20 minutes or when the volume ratio of the inert gas to the reactor volume per unit time exceeds 9 / hour, the amount of the inert gas per unit time supplied to the reaction tank is large. Become
In the case of blowing from an outlet having a predetermined diameter, the flow velocity is increased, the resistance to the stirring flow is increased, and the contact time is shortened because the gas passes through the reaction solution in a short time at the flow velocity. However, it may not always be possible to efficiently expel the inert gas. When the contact time exceeds 300 minutes or when the volume ratio of the inert gas per unit time to the reactor volume is less than 0.02 / hour, the amount of inert gas supplied per unit time is limited. Therefore, it is not possible to uniformly disperse the reactant in the reaction solution, and a reaction solution portion not in contact with the inert gas is formed, and the contact efficiency may be deteriorated.

The temperature conditions for bringing the reaction solution into contact with the inert gas are not particularly limited, as they may be before the temperature is raised to distill off the dehydrating solvent as described above. However, since it is desirable to start the process in the course of distilling off the dehydrating solvent as described above, the temperature in the system (temperature of the reaction solution (under normal pressure)) is 90
It is desirable that an inert gas be brought into contact with the reaction solution within a temperature range of -100 ° C. When it is out of the preferable range, that is, when the contact of the inert gas is started from less than 90 ° C.,
Undesirably, the dehydrated solvent during distillation does not remain, and the recovery rate of the dehydrated solvent is reduced and environmental pollution is caused.
If the temperature exceeds 100 ° C., the unreacted low-boiling material is azeotropic with water (specifically, the azeotropic temperature of acrylic acid-water is 99.85 ° C., the weight ratio is 0.4 / 99.6, and the weight ratio of methacrylic acid-water Has an azeotropic temperature of 99.3 ° C. and a weight ratio of 23.1 / 76.9.)
And polymerized in the line or condenser.

The pressure (vapor pressure) condition for bringing the inert gas into contact with the reaction solution is not particularly limited, and the reaction may be carried out at normal pressure, under pressure, or under reduced pressure. However, the temperature required for distilling off the dehydrating solvent and the azeotropic temperature of the unreacted low-boiling raw material and water also fluctuate depending on the pressure conditions, which makes it difficult to control, and also makes the dissolved dehydrating solvent inert. Even under the influence of the transfer speed to gas and the equipment (for example, the use of equipment such as the need for a pressure-resistant container is limited, etc.), even under normal pressure (about 1 kg /
cm ² ).

In the solvent distillation step, the conditions for distilling the dehydrated solvent out of the solution in the system are not particularly limited as long as the dehydrated solvent in the system can be suitably distilled (evaporated). Without being limited, the temperature in the system during the solvent distillation (liquid temperature in the system (under normal pressure)), for example,
When (1 ″) water is used, it is usually 80 to 120 ° C., preferably 90 to 110 ° C., and when (2 ″) water is not used, it is usually 80 to 160 ° C., preferably 90 to 15 ° C.
0 ° C. If the timing requirement for contacting the inert gas overlaps with the time for distilling off the dehydrating solvent, the temperature in the system at the time of contacting the inert gas and the temperature in the system during solvent distillation (the liquid in the system) Temperature), so it can be said that it may be controlled in any case. In any of the above (1 ") and (2"), if the temperature is lower than the temperature specified above, a temperature (calorific value) sufficient to evaporate the dehydrating solvent is used.
On the other hand, it is not preferable because it takes a long time to evaporate the dehydrating solvent. It is not preferable because it is consumed for evaporation. Also,
The pressure in the system (in the apparatus) may be either normal pressure or reduced pressure, but it is preferable to perform the pressure under normal pressure from the viewpoint of equipment. Further, as an apparatus system for distilling a solvent from a reaction solution containing a dehydrating solvent, the apparatus system (reaction tank) used in the esterification reaction is preferably used as it is. That is,
If the contents are separately transferred to another device after the esterification reaction, the equipment and management costs will increase, and in addition to the external factors (heat, light, transport temperature, transport pressure, Deterioration due to ambient gas),
It is necessary to prevent the substance from sticking in the transport route or to prevent impurities from being eluted or mixed in from the apparatus or the like during transport, which is not preferable because extra cost is generated.

The above is a detailed description of the method for producing an esterified product of the present invention.

Next, a method for producing a polymer using the esterified product of the present invention will be described below.

The process for producing a polymer using the esterified product of the present invention is carried out in a dehydrating solvent by the general formula (1)

[0068]

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(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 The repeating units of each R ² O may be the same or different, and when R ² O is in the form of a mixture of two or more types, the repeating units of each R ² O may be added in the form of a block or randomly. And n represents an average number of moles of the oxyalkylene group added, and 0 to 3
When an esterified product obtained by an esterification reaction between an alcohol represented by the formula (00) and (meth) acrylic acid is used as a monomer component, the polymerization reaction is carried out or after the polymerization reaction is carried out. It is characterized in that an inert gas is brought into contact with the reaction solution. That is, in the method for producing a polymer using the esterified product of the present invention, the esterified product (containing the residue of the dehydrated solvent) obtained by the esterification reaction in the dehydrated solvent can be handled without opening to the atmosphere. When the esterification product is used as an intermediate product and a polymerization reaction is immediately carried out in a reaction system (reaction apparatus), the problem due to the solvent odor does not occur even if the dehydration solvent remaining until the esterification product is obtained is not removed. The remaining dehydrated solvent may be driven out until the polymer finally obtained by the polymerization reaction is handled. This can solve the problem of bad smell due to the solvent smell when handling them, as described above.

Hereinafter, a preferred embodiment of the method for producing an esterified product of the present invention will be described step by step.

The method for producing a polymer using the esterified product of the present invention is as described above.
In a dehydrated solvent, an esterified product (an esterified product production process) obtained by an esterification reaction between an alcohol represented by the general formula (1) (hereinafter, also simply referred to as “alcohol”) and (meth) acrylic acid is used. When performing a polymerization reaction as a monomer component, it is desirable that an inert gas be brought into contact with the polymerization reaction solution, preferably after the polymerization reaction (polymerization step).

(I) Description of the process for producing the esterified product The process for producing the esterified product of the present invention is not particularly limited, and is carried out in the same manner as described in the method for producing the esterified product of the present invention. (However, here, it is not necessary to contact an inert gas with the reaction solution, particularly after the esterification reaction is completed), and a conventionally known method for producing an esterified product can be appropriately used. .

(II) Description of Polymerization Step A preferred embodiment of the above polymerization step will be described below.

In the polymerization step of the present invention, a polymer suitable for the intended use can be obtained by conducting a polymerization reaction using the esterified product obtained in the above-mentioned esterified product production process as a monomer component. There is no particular limitation as long as they are those described in JP-B-59-18338, JP-A-9-86990 and JP-A-9-28.
In the same manner as in a known method such as the method described in JP-A-6645, a (meth) acrylic acid (salt) and, if necessary, a monomer copolymerizable with a monomer component of these esterified products are subjected to a polymerization reaction. Can be offered. More specifically,
The esterified monomer is (meth) acrylic acid (salt)
It is subjected to a polymerization reaction together with a monomer and, if necessary, a monomer copolymerizable with these monomers.

Here, in order to obtain a desired polymer, it is only necessary to copolymerize the monomer components of the esterified product using a polymerization initiator. The copolymerization can be performed by a method such as polymerization in a solvent or bulk polymerization.

The polymerization in a solvent can be carried out either batchwise or continuously.
Water; lower alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane and 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 raw material esterified product and the obtained copolymer and the convenience of using the copolymer, at least one selected from the group consisting of water and lower alcohols having 1 to 4 carbon atoms. 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 the polymerization is carried out 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 can be used in combination. For polymerization using lower alcohols, aromatic hydrocarbons, aliphatic hydrocarbons, ester compounds or ketone compounds as solvents, peroxides such as benzoyl peroxide and lauroyl peroxide; hydroperoxides such as cumene hydroperoxide; An aromatic azo compound such as bisisobutyronitrile is used as a polymerization initiator. In this case, 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-mentioned various polymerization initiators or a combination of the polymerization initiator and the accelerator. The polymerization temperature is appropriately determined depending on the solvent and the polymerization initiator used.
It is performed within the range of 20 ° C.

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

For controlling the molecular weight of the obtained polymer, a thiol-based chain transfer agent can be used in combination. The thiol-based chain transfer agent used at this time has the general formula HS
-R ⁵ -E _g (provided that wherein R ⁵ represents an alkyl group having a carbon number of 1 to 2, E is -OH, -COOM ^2, -C
OOR ⁶ or —SO ₃ M ² represents a group, wherein M ² is hydrogen,
Represents a monovalent metal, a divalent metal, an ammonium group or an 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-mercaptopropionate, and the like. One or more of these can be used.

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

In the present invention, when the above-mentioned various polymerization reactions are performed and after the polymerization reaction is performed (for example, during the formation of a polymer salt by neutralization, or after the neutralization, and further, it is taken out of the system) (Before handling, there is no particular problem even after transport and storage in a storage tank in a closed system.)
Further, an inert gas is brought into contact with these polymerization reaction liquids. As a result, the dehydrating solvent remaining in the polymerization reaction solution (including the residue of the solvent separately used during the polymerization; hereinafter the same applies) can be expelled very efficiently by the inert gas, and the resulting polymer is dissolved in the solvent. Odor can be prevented from being generated.

Here, the inert gas used is:
If it is inert to the components of the polymerization reaction solution,
There is no particular limitation, and examples thereof include gases such as air, nitrogen gas, helium gas, argon gas, and carbon dioxide (preferably, a gas that does not contain water vapor). Air and nitrogen gas. These inert gases may be used alone or in a combination of two or more. Further, when the inert gas is brought into contact with the reaction solution during the polymerization reaction, the temperature of the polymerization reaction solution in the system does not fluctuate,
It is preferable to supply an inert gas previously heated to the same temperature as the liquid temperature by a suitable heating means.

The method of contacting the polymerization reaction solution with the inert gas in gas-liquid manner is not particularly limited. The inert gas may be flowed over the reaction solution to bring it into gas-liquid contact. Gas-liquid contact may be performed by blowing an inert gas into the inside, and the same method as in the above-described method for producing an esterified product, in which the inert gas is brought into contact with the reaction solution in a gas-liquid manner after the esterification reaction, can be applied. In addition, since it can be said that the preferred contact method is the same, a detailed description of the gas-liquid contact method of the inert gas with the polymerization reaction liquid is omitted here.

The amount of the inert gas required to drive out the remaining degreasing solvent is the same as that described in the method for producing the esterified product. That is, although depending on the contact method, the polymerization form (whether polymerization in an aqueous medium or polymerization in another solvent, etc.) and the timing of contact initiation, etc., usually, the polymerization reaction solution, An amount exceeding 10% by volume of the volume of the reactor (polymerization reaction tank), preferably 15 to 300% by volume, more preferably 20 to 200% by volume.
% By volume. When the amount of the inert gas used is 10% by volume or less of the capacity of the reactor, the dissolved dehydrating solvent cannot be driven out sufficiently, and the effect of removing the solvent odor is not sufficient. If the content exceeds 300% by volume, the intended purpose of driving out the dissolved dehydrated solvent is achieved, but the inert gas containing the dehydrated solvent recovered after gas-liquid contact is reused or discharged outside the system. Although it will be exhausted, in any case, it is necessary to separate and remove the dehydrating solvent from the inert gas.If a large amount of inert gas is used, the cost of the inert gas itself and the cost of its recovery are high. This is not preferred.

The relationship between the capacity of the reactor and the capacity of the weight reaction solution is that, in conducting the polymerization reaction, it is necessary to maintain the reaction solution at a predetermined temperature, and that the reaction solution is partially filled with the reaction solution in view of the reaction efficiency. It is desirable that the volume of the reaction solution in the reactor fluctuates due to the addition of an alkaline substance in the neutralization treatment after the polymerization reaction. The volume of the polymerization reaction solution at the start of the contact is approximately 30 to 90% of the volume of the reactor.
Range. This means that when an inert gas flows over the reaction surface of the reactor and comes into gas-liquid contact,
If there is an excessive volume of space above the surface of the reaction solution, the contact efficiency is poor and a large amount of inert gas needs to be ventilated. In addition, it is necessary to feed under pressure, and the inside of the tank may be pressurized. In the case where an inert gas is blown into the reaction solution in the reactor to make gas-liquid contact, the volume ratio of the polymerization reaction solution in the reactor does not matter.

As described above, when the contact of the polymerization reaction solution with the inert gas is started, the contact of the inert gas is started when the polymerization reaction is carried out (or before the start of the polymerization). Alternatively, gas-liquid contact of an inert gas may be performed during the polymerization reaction. On the other hand, after conducting the polymerization reaction (for example, before or during the formation of the polymer salt by neutralization, or after the neutralization, or before taking it out of the system and handling it, store it in a closed system. (It may be after transported to a tank or the like and stored), but the contact of the inert gas may be started.

In the case where the polymerization is carried out in a solvent other than water, the solvent used during the polymerization is distilled off.
At the stage when the solvent in the reactor has reached 1% by volume or less of the volume of the reactor, preferably in the range of 0.1 to 0.9% by volume, contact of the polymerization reaction solution with an inert gas is started. Is desirable. The concentration of the solvent remaining in the reactor (in the polymerization reaction liquid) (volume% based on the volume of the reactor) is a value measured by gas chromatogram analysis of the reaction liquid.

The time and flow rate of contacting the polymerization reaction solution with the inert gas may be appropriately determined so that the time and flow rate of the inert gas fall within the range of the usage amount of the inert gas specified above. However, even if a large flow of inert gas flows in a short time, it may not always be possible to efficiently expel the inert gas, and conversely, when flowing a small flow of inert gas over a long period of time, It becomes difficult to disperse the bubbles of the inert gas in the entire region of the tank in a state close to complete mixing, and the contact efficiency also deteriorates. In addition, since the contact time and the flow rate are also affected by the contact start timing and the temperature condition of the inert gas, it is inappropriate to univocally specify the contact time and the flow rate. The setting is not desirable, and the contact time is about 20 to 300 minutes, preferably 30 to 180 minutes, and the volume ratio of the inert gas to the reactor volume per unit time is 0.1.
It is desirable to carry out the reaction at a rate of 02 to 9 / hour, more preferably 0.03 to 6 / hour. When the contact time is less than 20 minutes or when the volume ratio of the inert gas per unit time to the volume of the reactor exceeds 9 / hour, the amount of the inert gas per unit time supplied to the polymerization reaction tank is reduced. In the case of blowing from an outlet having a predetermined diameter, the flow rate increases, and the resistance to the stirring flow increases.In addition, the contact time for passing through the polymerization reaction solution in a short time at the flow rate increases. In some cases, it is not always possible to efficiently expel the inert gas, for example, the length of the gas becomes shorter. When the contact time exceeds 300 minutes or when the volume ratio of the inert gas per unit time to the reactor volume is less than 0.02 / hour, the inert gas supplied per unit time is Because it is limited, it cannot be uniformly dispersed in the polymerization reaction liquid, and the reaction liquid part that is not in contact with the inert gas is formed,
Contact efficiency may be reduced.

The temperature condition for contacting the polymerization reaction solution with the inert gas is not particularly limited, as it may be before the temperature is raised for the polymerization reaction as described above. However, as described above, it is desirable to start after the polymerization reaction and before the temperature of the polymerization reaction solution falls, and the temperature in the system (temperature of the polymerization reaction solution) is 0 to 10
It is desirable that an inert gas be brought into contact with the polymerization reaction solution at a temperature of 0 ° C, more preferably 10 to 90 ° C.

The pressure (vapor pressure) condition for bringing the inert gas into contact with the polymerization reaction solution is not particularly limited, and it may be carried out at normal pressure, under pressure or under reduced pressure. Although good, the influence on the moving speed of the residual solvent to the inert gas and the equipment (for example, the use equipment is restricted such as the need for pressure-resistant containers, etc.), even under normal pressure ( It is desirable to carry out at about 1 kg / cm ² ).

The monomer component of the esterified product that can be used in the polymerization step is represented by the following general formula (2)

[0092]

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(However, R ¹ , R ² O and n are the same as those defined in the above general formula (1), and R ³ is a hydrogen atom or a methyl group). The monomer components of the esterification product may be used singly or as a mixture of two or more. In particular, when two or more kinds are used in combination, it is desirable to use a combination of different kinds of expression properties appropriately so that properties (functions, performances, etc.) according to the intended use can be exhibited. In the case of using as a cement dispersant as an example, the following two combinations are advantageous.

In the esterified product represented by the general formula (2), the average number of moles n added is an integer of 1 to 97, preferably 1 to 10. A first esterified product (a ¹⁾ represented by), the average addition mole number n is 4 to 100, preferably an integer of 11 to 100. The second indicated by
Esterified product (a ²⁾ a mixture of (provided that those who average addition mole number of the second esterified product (a ²⁾ is 3 or more larger than the average addition mol number of the first esterified product (a ¹⁾ ).

The method for producing such a mixture of the first esterified compound (a ¹ ) and the second esterified compound (a ² ) is as described in the above-mentioned step of producing the esterified compound. The first and second esterified products (a ¹ ) and (a ² ) may be separately produced by an esterification reaction, or may be produced by an esterification reaction of a corresponding alcohol mixture with a (meth) acrylic ester. It may be manufactured, and in particular, the latter method can provide an industrially inexpensive manufacturing method.

In this case, the weight ratio of the first esterified compound (a ¹ ) to the second esterified compound (a ² ) is 5: 95-9.
The ratio 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, and methoxy (poly) butylene glycol mono (meth) acrylate. ) 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) acryl Ethoxy (poly) propylene glycol mono (meth) acrylate, ethoxy (poly) butylene glycol mono (meth) acrylate, ethoxy (poly) ethylene glycol (poly) propylene glycol mono (eta) 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 ) has hydrophobicity in the short-chain alkoxypolyalkylene glycol in its side chain.

Further, from the viewpoint of easy copolymerization, the side chain preferably contains a large amount of ethylene glycol units. Therefore, (a ¹ ) is preferably an (alkoxy) (poly) ethylene glycol mono (meth) acrylate having an average addition mole number of 1 to 97, preferably 1 to 10.

Examples of the ^second esterified product (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, Examples include ethoxy polyethylene glycol (poly) propylene glycol mono (meth) acrylate, ethoxy polyethylene glycol (poly) butylene glycol mono (meth) acrylate, and ethoxy polyethylene glycol (poly) propylene glycol (poly) butylene glycol mono (meth) acrylate. You.

In order to obtain a high water-reducing property, it is necessary to disperse the cement particles by steric repulsion and hydrophilicity by an alkoxypolyalkylene glycol chain having an average addition mole number of the second esterified product (a ² ) of 4 to 100. is important. For this purpose, it is preferable that a large number of oxyethylene groups be introduced into the polyalkylene glycol chain, and a 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 (meth) acrylic acid (salt) monomer include acrylic acid, methacrylic acid, and monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts of these acids. And one or more of these can be used.

Further, examples of monomers copolymerizable with the monomer components of the esterified monomer and the (meth) acrylic acid (salt) monomer include maleic acid, fumaric acid, citraconic acid, mesaconic acid and the like. Dicarboxylic acids such as acids and itaconic acids;
These dicarboxylic acids and HO (R ¹¹ O) _r R ¹² (where R ¹¹ O represents a mixture of one or more oxyalkylene groups having 2 to 4 carbon atoms, and in the case of two or more, block May be added in a random or random manner, r is the average number of moles of the oxyalkylene group and represents an integer of 1 to 100, and R ¹² is hydrogen or a carbon atom having 1 to 22 carbon atoms, preferably Represents an alkyl group of 1 to 15); monoesters or diesters with alcohols represented by the following formulas: unsaturated amides such as (meth) acrylamide and (meth) acrylalkylamide; vinyls such as vinyl acetate and vinyl propionate Esters: vinylsulfonic acid, (meth) allylsulfonic acid, sulfoethyl (meth) acrylate, 2-methylpropanesulfonic acid (meth) acrylic acid Ruamido, unsaturated sulfonic acids and their monovalent metal salts, such as styrene sulfonic acid, divalent metal salts, Arumoniumu salts, organic amine salts; styrene, alpha
-Aromatic vinyls such as methylstyrene;
18, preferably 1 to 15 esters of a phenyl group-containing alcohol such as an aliphatic alcohol or benzyl alcohol with (meth) acrylic acid; polyalkylene glycol mono (meth) acrylate; polyalkylene glycol mono (meth) allyl ether And one or more of these can be used.

The weight average molecular weight of the polymer and / or polymer salt of the present invention is appropriately determined according to the purpose of use, and is not particularly limited. When used as the main component of
It is preferable to be in the range of 00000. If the weight average molecular weight is less than 500, the water dispersing performance of the cement dispersant decreases, which is not preferable. On the other hand, if the molecular weight exceeds 500,000, the water dispersibility of the cement dispersant and the ability to prevent slump loss are undesirably reduced.

The polymer (including a polymer salt) obtained by the above-mentioned polymerization step can be used as a main component of a cement dispersant having excellent cement dispersing ability, and a pigment such as calcium carbonate, carbon black, and ink. It can be used as a dispersant, scale inhibitor, gypsum / water slurry dispersant, CWM dispersant, thickener, and the like.

The above is a detailed description of the method for producing a polymer using the esterified product of the present invention.

[0106]

The present invention will be described more specifically with reference to the following examples. In the examples, unless otherwise specified,%
Represents parts by weight, and parts represents parts by weight.

Example 1 A jacketed glass reactor (content: 30 liters) equipped with a thermometer, a stirrer, a produced water separator, a reflux condenser as a condenser, and a nitrogen inlet tube was charged with methoxypoly (n = 2).
5) 16500 parts of ethylene glycol, methacrylic acid 4
740 parts, 235 parts of paratoluenesulfonic acid hydrate, 5 parts of phenothiazine and 1060 parts of cyclohexane were charged, and an esterification reaction was performed at a reaction temperature of 115 ° C. 2
It was confirmed that the esterification rate reached 100% in 0 hours.

The resulting esterification reaction solution (1) 2225
135 parts of 49% aqueous sodium hydroxide solution and water 48
90 parts was added to neutralize paratoluenesulfonic acid, 8 parts of hydroquinone was added, the temperature was raised to 105 ° C, and cyclohexane was distilled off azeotropically with water. The vapor pressure in the jacketed glass reactor was 1 kg / cm ² . The internal temperature of the jacketed glass reactor (temperature of the reaction solution) is 98 ° C
When the reaction liquid was raised, nitrogen was introduced into the reaction solution in the reactor at a rate of 18 l / hr for 90 minutes ((nitrogen flow rate × time / reactor volume) × 100 = equivalent to 90% by volume) and dissolved. Out of the cyclohexane. Then, conditioned water was added to obtain an 80% aqueous solution of the esterified product (1). With respect to the esterified product aqueous solution (1), the presence or absence of white turbidity was visually confirmed, and the presence or absence of cyclohexane odor was confirmed by smelling the nose with the nose, but neither was observed. Further, the gas chromatogram analysis of the reaction solution was used to measure the concentration of cyclohexane at the start of distillation in the cyclohexane distillation step and at the start of nitrogen blowing. As a result of the measurement, the cyclohexane concentration at the start of distillation was 4% by volume with respect to the capacity of the reactor, and the cyclohexane concentration at the start of nitrogen blowing was 0.47% by volume with respect to the capacity of the reactor. there were.

Next, 8200 parts by weight of water was charged into a glass reactor (containing 30 liters) equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser, and the reactor was stirred. 80 ° C under nitrogen atmosphere
Until heated. Next, a monomer mixture obtained by uniformly mixing 13100 parts by weight of the esterified aqueous solution (1) obtained by the esterification reaction and 694 parts of 14% mercaptopropionic acid as a chain transfer agent, and 1125 parts by weight of an 11% aqueous ammonium persulfate solution And the mixture was added dropwise over 4 hours and 5 hours, respectively, and further continued for 1 hour to maintain the reaction temperature at 80 ° C. to complete the polymerization reaction, and the weight average molecular weight (calculated as polyethylene glycol by GPC; hereinafter,
The same shall apply. ) A 20,000 polymer aqueous solution (1) was obtained. Further, the obtained polymer aqueous solution (1) was
The solution was neutralized with an aqueous sodium hydroxide solution until the pH became 7, thereby obtaining a polymer salt (1). With respect to the obtained polymer aqueous solution (1) and polymer salt (1), the presence or absence of cloudiness was visually confirmed, and the presence or absence of cyclohexane odor was confirmed by smelling with the nose, but neither was observed. Further, the concentration of cyclohexane in the obtained 40% by weight aqueous polymer solution (1) was measured by gas chromatogram analysis. As a result of the measurement, the cyclohexane concentration was 24 ppm with respect to the obtained 40% by weight polymer aqueous solution (1).

The reaction composition in the esterification step of this example,
The reaction conditions and the esterification ratio are shown in Table 1 below. Further, the composition in the neutralization step, the cyclohexane concentration at the start of distillation in the cyclohexane distillation step and the start of nitrogen blowing, the internal temperature (temperature of the reaction solution), the flow rate and time of nitrogen, the flow rate of nitrogen × time / Table 2 shows the volume ratio of the reactor, the presence or absence of turbidity and off-flavor of the obtained polymer aqueous solution, and the cyclohexane concentration of the polymer aqueous solution.

Example 2 Esterification reaction liquid (1) 22255 obtained in Example 1
135 parts of 49% aqueous sodium hydroxide solution and 489 parts of water
0 parts were added to neutralize paratoluenesulfonic acid, 8 parts of hydroquinone was added, the temperature was raised to 105 ° C, and cyclohexane was distilled off azeotropically with water. The vapor pressure in the jacketed glass reactor was 1 kg / cm ² . When the internal temperature (temperature of the reaction solution) of the jacketed glass reactor rose to 95 ° C., 18 liter / hr of nitrogen was introduced into the reaction solution in the reactor over 150 minutes ((flow rate of nitrogen × time) / Reactor volume) × 100 = 150% by volume
) And dissolved cyclohexane was expelled. Then, conditioned water was added to obtain an 80% esterified aqueous solution (2). With respect to the esterified product aqueous solution (2), the presence or absence of cloudiness was visually confirmed, and the presence or absence of cyclohexane was confirmed by smelling the nose with the nose, but neither was observed. Further, the gas chromatogram analysis of the reaction solution was used to measure the concentration of cyclohexane at the start of distillation in the cyclohexane distillation step and at the start of nitrogen blowing. As a result of the measurement, the cyclohexane concentration at the start of distillation was 4% by volume based on the capacity of the reactor, and the cyclohexane concentration at the start of nitrogen blowing was 0.35% by volume based on the capacity of the reactor. there were.

Next, 8200 parts by weight of water was charged into a glass reactor (containing 30 liters) equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser, and the reactor was stirred. 80 ° C under nitrogen atmosphere
Until heated. Next, 13100 parts by weight of an aqueous solution of the esterified product (2) obtained by the above esterification reaction and 14% mercaptopropionic acid 694 as a chain transfer agent.
Parts and a 1125 parts by weight aqueous 11% ammonium persulfate solution were added dropwise over 4 hours and 5 hours, respectively, and the reaction temperature was maintained at 80 ° C. for 1 hour, followed by polymerization. The reaction was completed to obtain a polymer aqueous solution (2) having a weight average molecular weight of 20,000. Further, the obtained polymer aqueous solution (2) was neutralized with a 15% aqueous sodium hydroxide solution until the pH reached 7, thereby obtaining a polymer salt (2). With respect to the resulting polymer aqueous solution (2) and polymer salt (2), the presence or absence of white turbidity was visually confirmed, and the presence or absence of cyclohexane odor was confirmed by smelling with the nose, but neither was observed. Further, the concentration of cyclohexane in the obtained 40% by weight aqueous polymer solution (2) was measured by gas chromatogram analysis. As a result of the measurement, the cyclohexane concentration was 33 ppm with respect to the obtained 40% by weight polymer aqueous solution (2).

The reaction composition in the esterification step of this example,
The reaction conditions and the esterification ratio are shown in Table 1 below. Further, the composition in the neutralization step, the cyclohexane concentration at the start of distillation in the cyclohexane distillation step and the start of nitrogen blowing, the internal temperature (temperature of the reaction solution), the flow rate and time of nitrogen, the flow rate of nitrogen × time / Table 2 shows the volume ratio of the reactor, the presence or absence of turbidity and off-flavor of the obtained polymer aqueous solution, and the cyclohexane concentration of the polymer aqueous solution.

Example 3 Esterification reaction solution (1) 22255 obtained in Example 1
135 parts of 49% aqueous sodium hydroxide solution and 489 parts of water
0 parts were added to neutralize paratoluenesulfonic acid, 8 parts of hydroquinone was added, the temperature was raised to 105 ° C, and cyclohexane was distilled off azeotropically with water. The vapor pressure in the jacketed glass reactor was 1 kg / cm ² . When the internal temperature (temperature of the reaction solution) of the jacketed glass reactor rose to 98 ° C., 15 liter / hr of nitrogen was introduced into the reaction solution in the reactor over 60 minutes ((flow rate of nitrogen × time). / Reactor volume) × 100 = equivalent to 50% by volume) to drive off the dissolved cyclohexane. And
Adjusted water was added to obtain an 80% esterified aqueous solution (3). With respect to the aqueous esterified product solution (3), the presence or absence of white turbidity was visually confirmed, and the presence or absence of the odor of cyclohexane was confirmed by smelling the nose with the nose, but neither was observed.
Further, the gas chromatogram analysis of the reaction solution was used to measure the concentration of cyclohexane at the start of distillation in the cyclohexane distillation step and at the start of nitrogen blowing. As a result of the measurement, the cyclohexane concentration at the start of distillation was 4% by volume with respect to the volume of the reactor, and the cyclohexane concentration at the start of nitrogen blowing was 0.50% by volume with respect to the volume of the reactor. there were.

Next, 8200 parts by weight of water was charged into a glass reactor (containing 30 liters) equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser, and the reactor was stirred. 80 ° C under nitrogen atmosphere
Until heated. Next, 13100 parts by weight of an esterified aqueous solution (3) obtained by the above esterification reaction and 14% mercaptopropionic acid 694 as a chain transfer agent.
Parts and a 1125 parts by weight aqueous 11% ammonium persulfate solution were added dropwise over 4 hours and 5 hours, respectively, and the reaction temperature was maintained at 80 ° C. for 1 hour, followed by polymerization. The reaction was completed to obtain a polymer aqueous solution (3) having a weight average molecular weight of 20,000. Further, the obtained polymer aqueous solution (3) was neutralized with a 15% aqueous sodium hydroxide solution until the pH reached 7, thereby obtaining a polymer salt (3). With respect to the obtained polymer aqueous solution (3) and polymer salt (3), the presence or absence of white turbidity was visually confirmed, and the presence or absence of cyclohexane odor was confirmed by smelling the odor with the nose, but neither was observed. Further, the concentration of cyclohexane in the obtained 40% by weight aqueous polymer solution (3) was measured by gas chromatogram analysis. As a result of the measurement, the cyclohexane concentration was 30 ppm with respect to the obtained 40% by weight polymer aqueous solution (3).

The reaction composition in the esterification step of this example,
The reaction conditions and the esterification ratio are shown in Table 1 below. Further, the composition in the neutralization step, the cyclohexane concentration at the start of distillation in the cyclohexane distillation step and the start of nitrogen blowing, the internal temperature (temperature of the reaction solution), the flow rate and time of nitrogen, the flow rate of nitrogen × time / Table 2 shows the volume ratio of the reactor, the presence or absence of turbidity and off-flavor of the obtained polymer aqueous solution, and the cyclohexane concentration of the polymer aqueous solution.

Comparative Example 1 Esterification reaction liquid (1) 22255 obtained in Example 1
135 parts of 49% aqueous sodium hydroxide solution and 489 parts of water
0 parts were added to neutralize paratoluenesulfonic acid, 8 parts of hydroquinone was added, the temperature was raised to 105 ° C, and cyclohexane was distilled off azeotropically with water. The vapor pressure in the jacketed glass reactor was 1 kg / cm ² . When the internal temperature of the jacketed glass reactor (temperature of the reaction solution) rose to 95 ° C., 18 liter / hr of nitrogen was introduced into the reaction solution in the reactor over 10 minutes ((flow rate of nitrogen × time). / Reactor volume) × 100 = 10% by volume) and dissolved cyclohexane was expelled. And
The adjusted water was added to obtain an 80% aqueous solution of a comparative esterified product (1). In the comparative esterified product aqueous solution (1), the presence or absence of white turbidity was visually confirmed, and the presence or absence of cyclohexane odor was confirmed by smelling the nose with the nose. Also, by gas chromatogram analysis of the reaction solution,
The cyclohexane concentration at the start of the distillation in the cyclohexane distillation step and at the start of the nitrogen blow were measured. As a result of the measurement, the cyclohexane concentration at the start of distillation was 4% by volume based on the capacity of the reactor, and the cyclohexane concentration at the start of nitrogen blowing was 0.45% by volume based on the capacity of the reactor. there were.

Next, 8200 parts by weight of water was charged into a glass reactor (containing 30 liters) equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser, and the reactor was stirred. 80 ° C under nitrogen atmosphere
Until heated. Next, 13100 parts by weight of a comparative aqueous solution of an esterified product (1) obtained by the above esterification reaction and 14% mercaptopropionic acid 69 as a chain transfer agent were used.
A monomer mixture obtained by uniformly mixing 4 parts and 1125 parts by weight of an 11% ammonium persulfate aqueous solution were added dropwise over 4 hours and 5 hours, respectively, and the reaction temperature was maintained at 80 ° C. for 1 hour. The polymerization reaction was completed to obtain a comparative polymer aqueous solution (1) having a weight average molecular weight of 20,000. Further, the obtained comparative polymer aqueous solution (1) was neutralized with a 15% aqueous sodium hydroxide solution to pH 7 to obtain a comparative polymer salt (1). For the obtained comparative polymer aqueous solution (1) and comparative polymer salt (1), the presence or absence of white turbidity was visually confirmed, and the presence or absence of cyclohexane odor was confirmed by smelling the nose with the nose. Did not. Further, the concentration of cyclohexane in the obtained 40% by weight aqueous solution of the comparative polymer (1) was measured by gas chromatogram analysis. As a result of the measurement, the cyclohexane concentration was 800 ppm with respect to the obtained 40% by weight comparative polymer aqueous solution (1).

Reaction composition in the esterification step of this comparative example,
The reaction conditions and the esterification ratio are shown in Table 1 below. Further, the composition in the neutralization step, the cyclohexane concentration at the start of distillation in the cyclohexane distillation step and the start of nitrogen blowing, the internal temperature (temperature of the reaction solution), the flow rate and time of nitrogen, the flow rate of nitrogen × time / Table 2 shows the volume ratio of the reactor, the presence or absence of turbidity and off-flavor of the obtained polymer aqueous solution, and the cyclohexane concentration of the polymer aqueous solution.

[0120]

[Table 1]

[0121]

[Table 2]

Reference Example A comparative polymer aqueous solution (1) obtained in Comparative Example 1 was placed in a glass reaction vessel (content: 30) equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser. Liters), the vapor pressure in the reactor was set to 1 kg / cm ² . While maintaining the internal temperature of the reactor (the temperature of the reaction solution) at 40 ° C., 1
8 liters / hr of nitrogen are introduced over 3 hours ((nitrogen flow rate × time / reactor volume) × 100 = 18)
(Equivalent to 0% by volume), and the dissolved cyclohexane was expelled to obtain a polymer aqueous solution (4). For the obtained polymer solution (4), as well as check for white turbidity visually, but the existence of cyclohexane odor by sniffing the nose was Check <br/>, was observed together. Further, the concentration of cyclohexane in the obtained 40% by weight aqueous polymer solution (4) was measured by gas chromatogram analysis. As a result of the measurement, the cyclohexane concentration was 20 ppm with respect to the obtained 40% by weight polymer aqueous solution (4).

[0123]

(1) In the method for producing an esterified product of the present invention, an esterification reaction between an alcohol represented by the above general formula (1) and (meth) acrylic acid is performed in a dehydrating solvent,
When the dehydration solvent is distilled off from the reaction solution after or after the esterification reaction, by contacting the reaction solution with an inert gas, the dehydration solvent can be sufficiently distilled off after the esterification reaction. , The dehydrated solvent dissolved in the reaction solution remains,
The reaction aqueous solution becomes cloudy, and when the esterified product is handled, for example, when the work is performed by opening to the atmosphere when performing storage or transport by taking out of the reaction system, the reaction solution remains in the reaction solution. The existing technical problem that the working environment of the handling operator deteriorates can be solved by evaporating (sustained release) of the dehydrated solvent that is present, and the working environment is extremely excellent. .

(2) In the present invention, in the method for producing an esterified product according to the above (1), an inert gas in an amount exceeding 10% by volume of the reactor capacity is brought into contact with the reaction solution. By doing so, the action and effect described in the above (1) can be exerted, and turbidity and an unpleasant odor (solvent odor) are caused in the aqueous solution of the obtained esterified product by any inert gas-liquid contact method. The concentration of the dehydrated solvent dissolved in the aqueous solution of the esterified product can be reduced to a level that cannot be confirmed (perceived) at times.

(3) Further, according to the present invention, the above (1)
Alternatively, in the method for producing an esterified product according to (2), when the amount of the dehydrated solvent becomes 1% by volume or less of the capacity of the reactor, contact of the reaction solution with an inert gas is started, whereby In addition to the effects described in (1) and (2), the dehydrated solvent can be distilled from the reaction solution without heating the reaction solution only to drive out the remaining dehydrated solvent by the gas-liquid contact treatment. By performing in the process of removing, it is possible to drive out the dehydrated solvent dissolved in the aqueous phase side by using only the amount of heat originally required for distillation,
Since the amount of heat used can be reduced, and most of the reaction solution remains as an aqueous solution, the inert gas can act extremely efficiently on the dehydrating solvent dissolved in the aqueous solution, and further, the gas It has the advantage that it is easy to recover the dehydrated solvent from the inert gas after being used for liquid contact.

(4) In the present invention, the above (1) to (3)
The method according to (1) to (3), wherein the reaction solution is brought into contact with an inert gas in the reactor at an internal temperature of 90 to 100 ° C. In addition to the effect, the dehydrated solvent in the distillate can be recovered extremely efficiently, and the risk of being disposed of outside the system is extremely low (sufficiently lower than the environmental standard value). Or, the ratio of low-boiling raw materials azeotropically azeotropic with water is extremely low. This is an extremely useful method that is also excellent.

(5) In the method for producing a polymer using the esterified monomer of the present invention, the esterification reaction between the alcohol represented by the general formula (1) and (meth) acrylic acid in a dehydrated solvent is carried out. The esterified product obtained by the above was used as a monomer component, when performing a polymerization reaction, or after performing the polymerization reaction, characterized by contacting an inert gas with respect to the polymerization reaction solution, was obtained. Even after producing a polymer that can be used for various applications using the esterified product, the dehydration solvent used during the esterification reaction remains in the polymerization reaction solution, and the polymerization reaction solution remains cloudy, for example, When the polymer is used for an application usually handled in a natural environment, such as a cement dispersant, the dehydrated solvent is vaporized (slowly released), so that a strong solvent smell is released, and Dispersant When compounding a cement composition by blending, it is possible to solve the conventional technical problem that the working environment of the worker handling the cement composition at a construction site or the like deteriorates, and the working environment is extremely excellent. I have.

(6) In the present invention, in the method for producing a polymer according to the above (5), an inert gas in an amount exceeding 10% by volume of the polymerization reactor is added to the polymerization reaction solution. By bringing the polymer into contact, the action and effect described in the above (5) can be exerted. In addition, particularly when the polymerization reaction is carried out in an aqueous medium, the polymer obtained can be obtained by any gas-liquid contact method with an inert gas. To reduce the concentration of the dehydrated solvent dissolved in the aqueous solution of the polymer (salt) to a level at which neither turbidity nor offensive odor (solvent odor) can be confirmed (not perceived) during the handling operation of the aqueous solution of the (salt). Can be done.

(7) Further, in the present invention, the above (5)
Alternatively, in the method for producing a polymer according to (6), when the solvent in the reactor becomes 1% by volume or less of the volume of the polymerization reactor, contact of the polymerization reaction solution with an inert gas is started. By doing so, the effects described in the above (5) and (6) can be exhibited, and in particular, when the polymerization reaction is carried out in a polymerization medium other than water, all the solvent including the remaining dehydrated solvent is brought into gas-liquid contact. The process is carried out in the process of distilling off the solvent from the polymerization reaction solution without heating the polymerization reaction solution only in order to drive it out by the treatment. Since the solvent dissolved on the phase side can be driven out, the amount of heat used can be reduced, and since most of the polymerization reaction solution remains as an aqueous solution, it is incompatible with the solvent dissolved in the aqueous solution. Make the active gas act very efficiently Can be further offers several advantages including it is easy to recover the dehydrating solvent from the inert gas after being used for the gas-liquid contact.

(8) In the present invention, the above (5) to (7)
In the method for producing a polymer according to the above, the inert gas is brought into contact with the polymerization reaction solution within a temperature range of 90 to 100 ° C. in the polymerization reactor, whereby the above (5) to (7) is described. In addition to the effects of the above, the solvent in the distillate can be recovered extremely efficiently, and the possibility of discharge to the outside of the system (atmosphere) is extremely low (sufficiently lower than the environmental standard value). It is a very useful method that does not bring.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-328346 (JP, A) JP-A-61-209275 (JP, A) JP-A-10-236859 (JP, A) International Publication 00/012577 (WO, A1) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 65/32-65/338

Claims (4)

(57) [Claims] 1. In a dehydrating solvent, a compound represented by the general formula (1): (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 the same.) And when R ² O is in the form of a mixture of two or more, the repeating units of each R ² O may be added in blocks or randomly. And n represents the average number of moles of the oxyalkylene group added and is a number from 0 to 300), and the esterification reaction between the alcohol and (meth) acrylic acid is carried out. A process for producing an esterified product, which comprises contacting the reaction solution with an inert gas in an amount exceeding 10% by volume of the reactor when or after removing the dehydrating solvent from the solution. 2. A reactor having a volume of 1
The method for producing an esterified product according to claim 1, wherein an amount of the inert gas exceeding 0% by volume is contacted for a period exceeding 10 minutes. 3. The method according to claim 1, wherein the dehydrating solvent is 1% by volume of the volume of the reactor.
3. The method for producing an esterified product according to claim 1, wherein contact of an inert gas with the reaction solution is started at the following stages. 4. An internal temperature of the reactor of 90 to 100 ° C.
The method for producing an esterified product according to any one of claims 1 to 3, wherein an inert gas is brought into contact with the reaction solution.