KR100650143B1 - A method for preparing alkoxy polyalkyleneglycol (meth)acrylate - Google Patents

Abstract

A method for preparing an alkoxypolyalkylene glycol (meth)acrylate is provided to inhibit undesired side reactions, to obtain excellent reaction stability, and to improve purity of the final product. The method for preparing an alkoxypolyalkylene glycol (meth)acrylate represented by the following formula 3 comprises a step of carrying out transesterification of an alkoxypolyethylene glycol represented by the following formula 1 with a (meth)acrylate represented by the following formula 2 in the presence of a mixed catalyst containing lithium hydroxide and calcium oxide. In the above formulae 1-3, R1 is a C1-C4 alkyl; R2O is a polyalkylene group formed by block or random addition of at least one C2-C4 oxyalkylene group; R3 is H or CH3; R4 is a C1-C4 alkyl; and each of m and n represents an average addition mole number, each being an integer of 1-50.

Description

Method for producing alkoxypolyalkylene glycol (meth) acrylate {A METHOD FOR PREPARING ALKOXY POLYALKYLENEGLYCOL (METH) ACRYLATE}

[Industrial use]

The present invention relates to a method for producing alkoxypolyalkylene glycol (meth) acrylate, and more particularly to a method for producing a high purity alkoxypolyalkylene glycol (meth) acrylate.

[Private Technology]

In general, a method for obtaining an alkoxypolyalkylene glycol (meth) acrylate includes a direct esterification method in which an alkoxypolyalkylene glycol and (meth) acrylic acid are reacted in the presence of an acid catalyst and the resulting water is removed out of the system. There is a transesterification reaction in which an alkoxypolyalkylene glycol and (meth) acrylate are reacted under a basic catalyst and the resulting alcohol is removed out of the system.

The direct esterification reaction in the presence of an acid catalyst uses a hydrocarbon solvent such as benzene or cyclohexane as a co-solvent to remove water produced as a by-product, and after the reaction, a strong acid catalyst such as sulfuric acid or paratoluenesulfonic acid, and an unreacted Since (meth) acrylic acid has to be removed, a large amount of wastewater is generated due to neutralization and washing with water, and there is a problem in that the process is long.

For this reason, transesterification reactions using inorganic base catalysts are currently mainly used.

Japanese Patent Laid-Open No. 1979-041815 discloses methyl methacrylate and 2-ethylhexanol in combination with lithium compounds such as lithium hydride, alkyl lithium, phenyl lithium, lithium aluminum hydride, lithium salts of organic or inorganic acids, lithium acetylacetonate, lithium A method for causing an accelerated ester substitution reaction with an oxide or a catalyst such as lithium metal is introduced.

Japanese Patent Application Laid-Open No. 1980-105676 introduces a method for synthesizing glycidyl (meth) acrylate by transesterification of methyl (meth) acrylate and glycidol in the presence of a halogenated alkali metal catalyst, particularly lithium chloride. .

Japanese Laid-Open Patent Publication No. 1980-127380 introduces a method for transesterifying glycidol and other organic carboxylic acid esters in the presence of a halogenated alkali metal catalyst, sodium bromide.

However, the transesterification catalysts used in these prior arts still have problems with product quality, environmental and economic problems, and in terms of process, there is a high risk of unnecessary polymerization during the reaction. There is a high possibility of side reactions due to selectivity.

Therefore, it is necessary to develop an economical and environmentally friendly process for obtaining a high quality ester compound under stable conditions.

The present invention is to solve the above problems, an object of the present invention is a method of economically producing a high yield of alkoxypolyalkylene (meth) acrylate in the production of waste water in a short process, less side reactions To provide.

In order to achieve the above object, the present invention provides an alkoxypolyalkylene glycol (meth) acrylate comprising a transesterification reaction of alkoxy polyethylene glycol and (meth) acrylate in the presence of a mixed catalyst of lithium hydroxide and calcium oxide Provide a method.

Hereinafter, the present invention will be described in more detail.

In the present invention, (meth) acrylate is used by the name including both methacrylate and acrylate.

Alkoxypolyethylene glycol (meth) acrylate is a monomer used as a raw material for the cement admixture, and the cement admixture prepared from the monomer has excellent dispersibility.

A method for producing an alkoxypolyalkylene glycol (meth) acrylate of the present invention is to prepare an alkoxypolyethylene glycol represented by the following formula (1) and (meth) acrylate represented by the following formula (2) in the presence of a mixed catalyst of lithium hydroxide and calcium oxide Exchange reaction.

[Formula 1]

[Formula 2]

[Formula 3]

Where

R ¹ is an alkyl group having 1 to 4 carbon atoms,

R ² O is a polyalkylene group in which one or two or more oxyalkylene groups having 2 to 4 carbon atoms are added in block form or added in random form,

R ³ is hydrogen or a methyl group,

R ⁴ is an alkyl group having 1 to 4 carbon atoms,

m and n are the integers of 1-50 each independently in the average added mole number of an oxyalkylene group.

Among the alkali catalysts used in the prior art, strong base catalysts such as sodium hydroxide are very sensitive to moisture, and therefore, an anhydride-type catalyst should be used because polymerization may occur when the moisture content of the raw material is high.

In addition, a strong base catalyst such as sodium hydroxide is likely to cause a polymerization reaction between (meth) acrylates and a polymerization reaction between alkoxypolyalkylene glycol (meth) acrylates during the transesterification reaction. In addition, when the alkali metal catalyst is used alone, side reactions such as the Michale addition reaction, the production reaction of the (meth) acrylate salt, and the like inevitably occur.

However, in the present invention, the weak base lithium hydroxide can be used to significantly reduce the possibility of side reaction polymerization, and the catalysis of lithium hydroxide can be further enhanced by the cocatalyst calcium oxide. Calcium oxide helps dissociation of lithium hydroxide, induces the transesterification reaction to proceed to the forward reaction, and plays a role of minimizing the delay and suppression of the reaction by the reverse reaction.

Lithium hydroxide used in the transesterification reaction of the present invention may be used both in the form of anhydride containing no water, or in the form of a hydrate in which water is present.

Therefore, in the present invention, a mixed catalyst containing lithium hydroxide and calcium oxide is used, and the use of the mixed catalyst increases the selectivity of the reaction, and the conversion rate is improved to obtain a high yield of the final product.

The lithium hydroxide catalyst and the calcium oxide catalyst may be used in a total amount injection method in which the entire amount is added before the start of the transesterification reaction, or a partial dropwise injection method in which the lithium hydroxide catalyst is periodically divided in the middle of the reaction.

The amount of each catalyst added in the transesterification step is not particularly limited, but in order to obtain a sufficient reaction rate, the amount of lithium hydroxide is preferably 0.1 parts by weight or more based on 100 parts by weight of alkoxy polyethylene glycol, and waste of the catalyst. The amount is preferably 5 parts by weight or less, and more preferably 0.2 to 1.5 parts by weight in order to facilitate the removal of the catalyst. Moreover, it is preferable that the addition amount of calcium oxide is 0.5-7 weight part with respect to 1 weight part of said lithium hydroxide.

The transesterification step is i) a mixed catalyst of lithium hydroxide and calcium oxide by mixing alkoxy polyethylene glycol represented by the formula (1) and (meth) acrylate represented by the formula (2) in a molar ratio of 1: 1 to 1:10. Reacting in the presence of, and ii) removing the azeotrope of (meth) acrylate and the reaction by-product alcohol (hereinafter referred to as 'produced alcohol') out of the reaction system and simultaneously removing the (meth) acrylate during the reaction. It is preferable to include a step of maintaining a molar ratio of 1: 1 to 1:10 of the alkoxy polyethylene glycol and the (meth) acrylate represented by the formula (2) by supplying a new.

Since the transesterification reaction is a reversible reaction in which the forward reaction and the reverse reaction occur at the same time, when a certain amount of the generated alcohol is present in the reaction system, the probability of occurrence of a reverse reaction that suppresses the forward reaction increases. Therefore, as the reaction proceeds, the produced alcohol must be removed to the outside without reflux into the reaction system, wherein unreacted (meth) acrylate is removed out of the reaction system together with the produced alcohol by azeotropic distillation.

Therefore, the (meth) acrylate in the reaction system is preferably present in excess of alkoxypolyethylene glycol, and in order to increase the conversion rate of the transesterification reaction, the initial molar ratio of alkoxypolyethylene glycol and (meth) acrylate is 1: 1 or more. In consideration of problems such as process time and energy for removing excess unreacted (meth) acrylate and yield of the final product, the initial molar ratio is preferably 1:10 or less, and 1: 2 to 1: 7. More preferred. However, the upper limit of the molar ratio does not limit the scope of the invention, which means that a maximum of about 1:10 is sufficient.

In addition, since the amount of unreacted (meth) acrylate is also removed in the step of removing the produced alcohol, as the reaction proceeds, the molar ratio of (meth) acrylate to the alkoxypolyethylene glycol gradually decreases, and the preferred molar ratio. In order to maintain the (meth) acrylate must be newly supplied to the reaction system.

At this time, the (meth) acrylate is preferably added so that the molar ratio of the alkoxy polyethylene glycol and the (meth) acrylate in the reaction system is 1: 1 to 1:10. Also in this case, the upper limit of the molar ratio is not limited, meaning that 1:10 is sufficient.

The method of removing the generated alcohol is the same as the conventional method, and can be removed by appropriately adjusting the pressure and temperature of the reaction system, the detailed description thereof is omitted in the present invention.

However, since the change in enthalpy (ΔH) of the overall reaction in the transesterification step is a negative value (−), it corresponds to an exothermic reaction that generates heat of reaction. In the reaction step, side reactions in which (meth) acrylates are produced may occur, and control of the reaction temperature is very important because such side reactions occur better at higher reaction temperatures.

Therefore, in order for the transesterification reaction to occur smoothly, the reaction temperature is preferably 50 ° C. or higher, and in order to prevent generation of oligomers due to heat generation and polymerization (Polymerization), the reaction temperature is preferably 95 ° C. or lower, and 70 to 95 ° C. More preferred. Products that produce a lot of oligomers may have problems of poor filter during the filtration process, in addition to the problem of poor polymer properties after polymerization.

In addition, the reaction can be carried out at both normal and reduced pressure, but in order to increase the reaction rate and effectively remove the produced alcohol and the like, it is preferable to keep the reaction at 500 torr or less, and in order to prevent the reaction system from excessively boiling. It is preferable that the pressure is 200 torr or more.

The reaction of the present invention can be carried out in a reactor equipped with a packed column for separating (meth) acrylate and alcohol from the (meth) acrylate / alcohol mixture in a vaporized state. In order to effectively control the supply amount of (meth) acrylate, the temperature of the packed column is preferably maintained at 30 to 90 ℃.

In the packed column, particles having a large surface area are preferably filled, and more preferably, lash healing is filled in a glass tube shape of 0.2 to 0.5 cm in length. The vaporized materials pass through filled short tubular lashings, causing partial separation of the low-boiling and high-boiling materials, with some of the high-boiling material (meth) acrylate going back into the reactor and some producing It is removed out of the reaction system with the alcohol.

However, the size of the rash healing is described as an example, and can be adjusted according to the size of the reactor is not limited to the above range in the present invention.

The reaction time can be adjusted in an appropriate range in consideration of the yield and the process time of the reaction, but the reaction is preferably carried out for 1 hour or more, and the reaction time is preferably 9 hours or less to prevent waste of the process time. More preferably 3 to 8 hours.

In order to prevent unnecessary polymerization in the transesterification step, it is preferable to add a polymerization inhibitor together with the polymerization reaction. Preferred examples of the polymerization inhibitor include 3-butylcatechol, phenol, aminophenol, diphenolamine, phenyl-beta-naphthalamine, hydroquinone monomethyl ether, t-butylhydroxytoluene, 2,4-dimethyl6-t At least one selected from the group consisting of -butylphenol and phenothiazine, among which, it is more effective to use hydroquinone monomethyl ether in view of the color of the final product and the reactivity when applied to the polymerization reaction. to be. Moreover, you may make it react, introducing oxygen into a reaction liquid as needed.

The polymerization inhibitor is preferably added in an amount of 0.01 parts by weight or more based on 100 parts by weight of the total amount of alkoxy polyethylene glycol and (meth) acrylate in order to prevent the occurrence of excessive polymerization of (meth) acrylate, and the final product is alkoxy polyethylene glycol. In order to prevent the reaction characteristic deterioration at the time of polymerization of (meth) acrylate, it is preferable to add in 1 weight part or less, and it is more preferable to add in 0.1-0.3 weight part.

The progress of the transesterification reaction is judged from the analysis of the composition of the reaction solution using liquid chromatography, hydroxyl group measurement (OH value measurement) and the like, and the amount of alcohol produced. To finish.

Since the alkoxypolyalkylene glycol used in the reaction cannot be removed because the boiling point is very high, it is preferable to control the conversion rate at the reaction of 99.5% or more.

After the reaction is completed, a significant amount of unreacted (meth) acrylate is present in the reactant in addition to the produced alkoxypolyalkylene glycol (meth) acrylate.

Therefore, after the transesterification reaction, it is preferable to proceed with the step of removing the unreacted (meth) acrylate from the reaction product, the reaction is completed, the step of removing the unreacted (meth) acrylate using a conventional vacuum distillation method Can be. At this time, the decompression conditions are not particularly limited, but it is preferable to set it as 200 to 40 torr at 70 to 90 ° C in view of shortening of the process time.

In addition, lithium hydroxide, which is used as a catalyst, and calcium oxide are present in the reactant in addition to unreacted (meth) acrylate, and salts generated by side reactions may also be present as solid impurities. Therefore, it is preferable that the manufacturing method of the present invention further includes the step of removing these impurities.

The order of the impurity removal step and the removal of the unreacted (meth) acrylate is not particularly limited, but if the impurity removal step is performed first, the filtration workability may deteriorate due to the smell of the unreacted (meth) acrylate. It is preferable to remove (meth) acrylate first.

The impurities may be removed by a general filtration method, and more preferably, may be removed by vacuum suction filtration using diatomaceous earth or pressure filtration. At this time, the amount of diatomaceous earth is preferably 0.05 parts by weight or more based on 100 parts by weight of the alkoxypolyalkylene glycol (meth) acrylate produced to completely remove the catalyst and side reaction salt, 5.0 in view of the filtration rate and waste generation amount It is preferable that it is below a weight part. Hereinafter, preferred embodiments of the present invention are described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

EXAMPLE

Example 1

9 kg (15 moles) of methoxypolyethylene glycol # 600 (average moles of oxyethylene groups: 13 moles), methyl methacrylate, in a 20 liter reactor equipped with a stirrer, a thermometer, and a packed column packed with rash healing. 4.5 kg (45 mol), 40.6 g of lithium hydroxide monohydrate, 130.5 g of calcium oxide, and 9 g of hydroquinone monomethyl ether were added, and the mixture was heated and stirred at 80 to 85 ° C. for 6 hours under a reduced pressure of 400 torr. Proceeded.

The reaction mixture was heated to reflux in the course of the reaction, the reflux ratio was adjusted to maintain the temperature of the top of the packed column in the range of 55 to 65 ℃ and the resulting methyl alcohol was removed as azeotrope with methyl methacrylate.

At this time, methyl methacrylate was constantly introduced into the reactor at a rate of 3 kg / hr (30 mol / hr) to adjust the reaction molar ratio of methyl methacrylate and methoxypolyalkylene glycol in the reaction system.

After completion of the transesterification reaction, the pressure was gradually reduced from 400 torr to 40 torr to remove unreacted methyl methacrylate, and 300 g of diatomaceous earth was put into a reactor and filtered under reduced pressure to 100 torr again.

Purity of the methoxy polyethylene glycol methyl methacrylate obtained in the reaction was measured by using NMR and liquid chromatography, the yield is obtained through the final reduced pressure filtration relative to the theoretical production of methoxy polyethylene glycol glycol (meth) acrylate Calculated from the weight ratio of.

Example 2

Methoxypolyethylene glycol # 1000 (average added moles of oxyethylene group: 23 mol) 9 kg (9 mol), 3 kg (30 mol) methyl methacrylate, 40.6 g of lithium hydroxide monohydrate, 130.5 g of calcium oxide, and hydroquinone A methoxy polyethylene glycol methyl methacrylate was prepared in the same manner as in Example 1 except that 9 g of monomethyl ether was added and the reaction was performed for 7 hours.

Example 3

Methoxypolyethylene glycol # 430 (average added moles of oxyethylene group: 9 mol) 9 kg (21 mol), 6 kg (60 mol) methyl methacrylate, 40.6 g of lithium hydroxide monohydrate, 130.5 g of calcium oxide, and A methoxypolyethylene glycol methyl methacrylate was prepared in the same manner as in Example 1 except that 9 g of hydroquinone monomethyl ether was added and the reaction was performed for 5 hours.

Example 4

Methoxypolyethylene glycol # 1300 (average added moles of oxyethylene group: 30 moles) 9 kg (6.9 moles), methyl methacrylate 2.1 kg (21 moles), lithium hydroxide monohydrate 40.6 g, calcium oxide 130.5 g, hydroquinone mono A methoxypolyethylene glycol methyl methacrylate was prepared in the same manner as in Example 1 except that 9 g of methyl ether was added and the reaction was performed for 8.5 hours.

Example 5

Methoxypolyethylene glycol # 600 (average added moles of oxyethylene group: 13 moles) 9 kg (15 moles), 4.5 kg (45 moles) methyl methacrylate, 40.6 g of lithium hydroxide monohydrate, 130.5 g of calcium oxide, and hydroquinone 9 g of monomethyl ether was added and the reaction proceeded for 20 hours, and methoxy polyethylene glycol methyl methacrylate was prepared in the same manner as in Example 1 except that no additional methyl methacrylate was added to the reactor. .

Example 6

Methoxypolyethylene glycol # 600 (average added moles of oxyethylene group: 13 moles) 9 kg (15 moles), 15 kg (150 moles) methyl methacrylate, 40.6 g of lithium hydroxide monohydrate, 130.5 g of calcium oxide, and hydroquinone 9 g of monomethyl ether was added and the reaction proceeded for 14 hours, and methoxy polyethylene glycol methyl methacrylate was prepared in the same manner as in Example 1 except that no additional methyl methacrylate was added to the reactor. .

Example 7

Methoxypolyethylene glycol # 600 (average added moles of oxyethylene group: 13 moles) 9 kg (15 moles), 4.5 kg (45 moles) methyl methacrylate, 40.6 g of lithium hydroxide monohydrate, 130.5 g of calcium oxide, and hydroquinone 9 g of monomethyl ether was added and the reaction proceeded for 9 hours. Methyl methacrylate was added to the reactor in the same manner as in Example 1 except that 1.5 kg / hr (15 mol / hr) was added to the reactor. Methyl methacrylate was prepared.

Comparative Example 1

40.6 g of lithium hydroxide monohydrate was used as a single catalyst and methoxy polyethylene glycol methyl methacrylate was prepared in the same manner as in Example 1 except that the reaction was carried out for 7 hours.

Comparative Example 2

30 g of sodium hydroxide was used as a monocatalyst, and the reaction proceeded for 3 hours, and methyl methacrylate was not added to the reactor in the same manner as in Example 1, except that methoxy polyethylene glycol methyl methacrylate was used. Was prepared.

The reaction was terminated due to polymerization occurring in 3 hours, conversion measurement was impossible, and filtration was impossible.

Reaction time, conversion rate, selectivity, side reactions of the methoxy polyethylene glycol methyl methacrylate obtained from the process according to Examples 1 to 7 and the process according to Comparative Examples 1 to 2, and the production rate of the methyl methacrylate salt as a side reaction, And final purity is summarized in Table 1 below.

Conversion was measured by liquid chromatography.

Selectivity was measured by NMR and liquid chromatography methods.

The incidence of side reactions was calculated from NMR and the amount of salt precipitated upon filtration.

Final purity was determined by NMR and liquid chromatography.

 TABLE 1

catalyst Response time (hrs) Additional MMA % Conversion Selectivity (%) Polymerization rate (%) Final purity (%) Example 1 Mixed catalyst 6 50 g / min 100 98 0 ＞ 99.5 Example 2 Mixed catalyst 7 50 g / min 100 98 0 ＞ 99.5 Example 3 Mixed catalyst 5 50 g / min 100 98 0 ＞ 99.5 Example 4 Mixed catalyst 8.5 50 g / min 100 98 0 ＞ 99.5 Example 5 Mixed catalyst 20 0 91 98 0 91 Example 6 Mixed catalyst 14 0 97 98 0.1 97 Example 7 Mixed catalyst 9 1.5 kg / hr 100 98 0 ＞ 99.5 Comparative Example 1 LiOH alone 7 3 kg / hr 99 85 0 85 Comparative Example 2 NaOH alone 3 0 - - ＞ 20 -

As shown in Table 1, the production method of the present invention can be seen that the conversion and selectivity is high, the reaction time is short, the side reaction occurrence rate is significantly low.

 In the production method of the present invention, not only the side reaction is suppressed, the reaction selectivity is high, the polymerization reaction is suppressed, and the reaction stability is excellent.

Claims (10)

The alkoxypolyalkylene glycol of the formula (3) comprising the step of transesterifying the alkoxypolyethylene glycol represented by the formula (1) and the (meth) acrylate represented by the formula (2) in the presence of a mixed catalyst of lithium hydroxide and calcium oxide (meta A method of making the acrylate: [Formula 1]

[Formula 2]

[Formula 3]

Where R ¹ is an alkyl group having 1 to 4 carbon atoms, R ² O is a polyalkylene group in which one or two or more oxyalkylene groups having 2 to 4 carbon atoms are added in block form or added in random form, R ³ is hydrogen or a methyl group, R ⁴ is an alkyl group having 1 to 4 carbon atoms, m and n are the integers of 1-50 each independently in the average added mole number of an oxyalkylene group. The method of claim 1, In the transesterification step, the amount of lithium hydroxide is included in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of alkoxypolyethylene glycol, and the amount of calcium oxide is 0.5 to 7 parts by weight based on 1 part by weight of the lithium hydroxide. Method for producing lene glycol (meth) acrylate. The method of claim 1, The transesterification step is i) mixing the alkoxy polyethylene glycol represented by Chemical Formula 1 and the (meth) acrylate represented by Chemical Formula 2 in a molar ratio of 1: 1 to 1:10 to react in the presence of a mixed catalyst of lithium hydroxide and calcium oxide; And ii) while removing the azeotrope of (meth) acrylate and the alcohol by-product of the reaction out of the reaction system during the reaction, the (meth) acrylate is newly supplied to the reaction system to represent the alkoxypolyethylene glycol and the formula (2) Maintaining a molar ratio of 1: 1 to 1:10 of acrylate Method for producing alkoxypolyalkylene glycol (meth) acrylate comprising a. The method of claim 1, The transesterification step is a method for producing an alkoxypolyalkylene glycol (meth) acrylate to maintain the reaction temperature of the reaction system at 50 to 95 ℃, the reaction pressure of the reaction system at 200 to 500 torr. The method of claim 1, The transesterification step is 3-butylcatechol, phenol, aminophenol, diphenolamine, phenyl-beta-naphthalamine, hydroquinone monomethyl ether, t-butylhydroxytoluene, 2,4-dimethyl-6-t A method for producing an alkoxypolyalkylene glycol (meth) acrylate, which is further proceeded by further adding at least one polymerization inhibitor selected from the group consisting of -butylphenol and phenothiazine. The method of claim 5, The polymerization inhibitor is a method for producing an alkoxypolyalkylene glycol (meth) acrylate is added to 0.01 to 1 part by weight of 100 parts by weight of alkoxy polyethylene glycol and (meth) acrylate. The method of claim 1, The preparation method further comprises the step of removing the unreacted (meth) acrylate from the reaction is completed after the transesterification reaction alkoxypolyalkylene glycol (meth) acrylate. The method of claim 7, wherein The step of removing the unreacted (meth) acrylate is a method for producing an alkoxypolyalkylene glycol (meth) acrylate using a vacuum distillation method. The method of claim 1, The method of producing alkoxypolyalkylene glycol (meth) acrylate further comprises the step of removing the lithium hydroxide, calcium oxide, and side reaction salt from the reaction is completed after the transesterification reaction. The method of claim 9, Removing the lithium hydroxide, calcium oxide, and the side reaction salt is a method for producing an alkoxypolyalkylene glycol (meth) acrylate by vacuum suction filtration using diatomaceous earth, or pressure filtration.