KR101590446B1 - Method for preparing highly pure epoxy reactive diluent modified with branched monocarboxylic acid - Google Patents

Abstract

The present invention relates to a process for preparing a high-purity branched monocarboxylic acid-modified epoxy reactive diluent, and more particularly, to a process for producing a high purity branched monocarboxylic acid-modified epoxy reactive diluent without a volatile organic substance in a wide range of resin coatings and coating applications such as epoxy, unsaturated polyester, alkyd, and urethane To a process for preparing a high-purity branched monocarboxylic acid-modified epoxy reactive diluent usable as a viscosity modifier.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for preparing a high-purity branched monocarboxylic acid-modified epoxy reactive diluent,

The present invention relates to a process for preparing a high-purity branched monocarboxylic acid-modified epoxy reactive diluent, and more particularly, to a process for producing a high purity branched monocarboxylic acid-modified epoxy reactive diluent without a volatile organic substance in a wide range of resin coatings and coating applications such as epoxy, unsaturated polyester, alkyd, and urethane To a process for preparing a high-purity branched monocarboxylic acid-modified epoxy reactive diluent usable as a viscosity modifier.

The branched monocarboxylic acid-modified epoxy reactive diluent is a compound having a primary addition reaction in which epichlorohydrin is additionally bound to a branched monocarboxylic acid in the presence of a metal ammonium catalyst and a primary addition reaction in which the hydrolyzable chlorine atom structure in the primary addition polymerization product is alkaline Can be obtained by a second-stage epoxy ring-closing reaction which is ring-opened by a metal catalyst, that is, caustic soda to form an epoxy functional group. The detailed reaction mechanism is as follows.

[Reaction Mechanism in the Preparation of Bifurcated Monocarboxylic Acid Modified Epoxy Reactive Diluent]

Primary addition reaction: branched Monocarboxylic acid and Epichlorohydrin  Additional binding

Secondary epoxy Ring closure reaction

(Wherein R1, R2 and R3 are organic groups such as an alkyl group).

However, when caustic soda used as a catalyst in each reaction step of the above-described mechanism is added in the form of aqueous solution, hydrolysis proceeds as follows by the water in the caustic soda solution and the reaction condensation water generated during the secondary epoxy cyclization reaction, Hydrolysis residues are generated due to the progress of the decomposition, and problems such as an increase in the epoxy equivalent, an increase of the side reactant content, and an increase in the viscosity are caused by the participation of the hydrolysis residue in the reaction mixture. The mechanism of this hydrolysis reaction is as follows.

[Mechanism of hydrolysis reaction]

reaction Intermediate  Hydrolysis

Hydrolysis of the final compound

(Wherein R1, R2 and R3 are organic groups such as an alkyl group).

When such a hydrolyzate is generated, a large amount of side reaction occurs due to the nature of the epoxy functional group exhibiting strong reactivity under strong alkaline conditions, resulting in problems such as lowered purity, lowered functional group content, increased viscosity, and color change do.

Korean Patent Registration No. 10-0663575 discloses a process for the preparation of epihalohydrin, which comprises adding a water-soluble alcohol stabilizer and water in the addition reaction of a monocarboxylic acid and an epihalohydrin, adding a metal hydroxide to the addition reaction and adding an equimolar amount of a metal hydroxide There has been disclosed a method for producing a glycidyl ester of a side chain carboxylic acid by proceeding with an epoxy ring closure reaction by adding a side chain. However, in this case, moisture remains in the reaction system and the hydrolysis and side reaction are more likely to occur , Lowering of epoxy functional group content and viscosity increase due to lowering of purity, discoloration and the like may occur.

Korean Patent Laid-Open Publication No. 10-2012-0016313 discloses a method for producing glycidyl ester of branched monocarboxylic acid by adding metal hydroxide of 1.4 to 1.6 times mol per mol of monocarboxylic acid in the ring closure reaction (epoxy ring-closing reaction) Lt; / RTI > However, when an excessive amount of a strong alkali metal hydroxide is added in the presence of moisture in the reaction system during the cyclization reaction, hydrolysis and side reactions are accelerated to decrease the content of epoxy functional groups, increase viscosity, Can cause problems.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made in an effort to solve the problems of the prior art as described above, and it is an object of the present invention to minimize the occurrence of hydrolysis and side reactions during the epoxycycloalkane reaction in the production of a branched monocarboxylic acid- To provide a method capable of producing a branched monocarboxylic acid-modified epoxy reactive diluent with high purity.

In order to accomplish the above object, the present invention provides a process for producing polylactic acid comprising the steps of (1) subjecting a branched monocarboxylic acid and epichlorohydrin to an addition reaction in the presence of a catalyst; (2) performing epoxycyclohexylation reaction of the resultant addition product of step (1) while azeotropically boiling water and epichlorohydrin and refluxing epichlorohydrin under the presence of metal hydroxide and under reduced pressure; (3) removing unreacted epichlorohydrin from the resulting mixture of step (2); (4) adding metal hydroxide to the result of step (3), stirring, and then separating the upper organic layer; And (5) adding a nonpolar organic solvent and water to the organic layer collected as a result of the step (4), stirring the mixture, separating the upper organic layer and removing the nonpolar organic solvent therefrom, There is provided a process for producing a terpene monocarboxylic acid-modified epoxy reactive diluent.

According to the present invention, it is possible to provide an epoxy resin composition which has excellent viscosity control ability by realizing an excellent curing reaction participation rate and low viscosity when applied to an epoxy curing type paint due to high epoxy functional group content and also has a hydrolyzable chlorine Min and a high-purity branched monocarboxylic acid-modified epoxy reactive diluent having a low ionic impurity content can be produced.

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

In the step (1) of the method for producing a branched monocarboxylic acid-modified epoxy reactive diluent of the present invention, a branched monocarboxylic acid and epichlorohydrin are addition-reacted in the presence of a catalyst.

Examples of the catalyst that can be used in step (1) include metal ammonium catalysts such as tetramethylammonium chloride and tetraethylammonium chloride, and alkali metal catalysts such as sodium hydroxide and potassium hydroxide. However, And any known catalyst known to be usable for the addition reaction of carboxylic acid with epichlorohydrin can be used without limitation. There is no particular limitation on the amount of the catalyst to be used. For example, 0.01 to 1 part by weight of the catalyst may be used based on 100 parts by weight of the sum of the branched monocarboxylic acid and epichlorohydrin as reactants.

Examples of the branched monocarboxylic acid usable in the step (1) include branched alkanoic monocarboxylic acids having 3 to 20 carbon atoms, more preferably 5 to 15 carbon atoms, and more specifically, But are not limited to, neodecanoic acid, 2-ethylnucleosanoic acid, and the like, but are not limited thereto and can be used without limitation as long as they can react with epichlorohydrin to form a modified epoxy reactive diluent.

The amount of the branched monocarboxylic acid and epichlorohydrin to be used in the step (1) is preferably 1: 2 to 1: 5, more preferably 1: 2.5 to 1: 4. If the amount of epichlorohydrin to be used is too small as compared with the branched monocarboxylic acid, there may be a problem that the molecular weight increase and the epoxy equivalent are increased due to the side reaction. On the contrary, when the amount of epichlorohydrin is excessively large, There may be a problem that the process takes a long time.

In the step (1), the addition reaction conditions of the branched monocarboxylic acid and epichlorohydrin are not particularly limited, and known reaction conditions may be used as they are or appropriately modified. Concretely, the reaction of step (1) may be carried out at atmospheric pressure at 70 to 100 ° C (more preferably at 80 to 90 ° C) for 1 to 4 hours (more preferably for 1.5 to 3 hours) But is not limited thereto.

In the step (2) of the method for producing a branched monocarboxylic acid-modified epoxy reactive diluent of the present invention, water and epichlorohydrin are azeotropically mixed with water in the presence of a metal hydroxide and under reduced pressure, and epichlorohydrin is refluxed The epoxy cyclization reaction of the resultant addition product of step (1) is carried out.

Examples of the metal hydroxide which can be used as the catalyst in the step (2) include caustic soda (sodium hydroxide), potassium hydroxide, and the like, but the present invention is not limited thereto. Can be used without limitation. There is no particular limitation on the amount of the metal hydroxide used in the step (2), and the molar ratio of the branched monocarboxylic acid: metal hydroxide is preferably 1: 0.9 to 1: 1.1, more preferably 1: 0.95 to 1: 1.05 Of the metal hydroxide is more preferable.

The pressure in the reactor is preferably 100 to 200 torr, more preferably 120 to 180 torr, and even more preferably 130 to 170 torr. (2) If the pressure of the step reaction is less than 100 torr, there may be a problem that the reflux process is not smooth due to the excessive leakage of reactants and residual epichlorohydrin, and when the pressure exceeds 200 torr, the water remaining in the reaction system is effectively removed There is a possibility that hydrolysis and side reaction are caused by residual moisture.

The temperature condition of the step (2) is preferably 50 to 70 ° C, more preferably 60 to 65 ° C. If the temperature condition of the step (2) reaction is less than 50 캜, there may be a problem that the epoxy ring-closing reaction can not be performed smoothly, and if it exceeds 70 캜, there may be a problem of increase in molecular weight and epoxy equivalent due to side reaction.

In the conventional processes, the ring-closing reaction is carried out while moisture generated during the epoxy ring-closing reaction corresponding to the step (2) is left in the reaction system. However, in the present invention, the decompression is performed during the ring- Continue to remove and proceed the reaction. More specifically, when the inside of the reaction vessel is maintained at a constant temperature and a reduced pressure, azeotropic distillation occurs due to decompression, and the effluent discharged as azeotropic distillation is discharged as a mixture of water and excess epichlorohydrin, The effluent is transferred to a separator and is phase separated by moisture and epichlorohydrin due to the specific gravity difference, and epichlorohydrin having relatively high specific gravity is trapped in the phase separated phase. The collected epichlorohydrin is re-introduced into the reaction tank to keep the concentration of epichlorohydrin in the reaction system constant. When the water is removed by using the decompression azeotropic distillation phenomenon, it is possible to effectively remove water even at a temperature significantly lower than 100 ° C required for removing water at normal pressure, thereby preventing hydrolysis due to moisture retention and side reaction And the side reaction between the reaction products can be prevented by keeping the concentration of epichlorohydrin in the reaction system constant.

In the step (3) of the method for producing a branched monocarboxylic acid-modified epoxy reactive diluent of the present invention, unreacted epichlorohydrin is removed from the resultant mixture of the step (2). The removal of epichlorohydrin can be carried out under elevated temperature and reduced pressure conditions. Specifically, the reaction mixture is heated to 110 to 140 ° C (more specifically, 120 to 130 ° C) after completion of the reaction in step (2) The residual epichlorohydrin can be removed by increasing the decompression degree in the stepwise manner to a final pressure of 10 torr or less (for example, 1 to 10 torr).

In step (4) of the method for producing a branched monocarboxylic acid-modified epoxy reactive diluent of the present invention, metal hydroxide is added to the resultant product of step (3), and the mixture is subjected to layer separation to collect an upper organic layer .

Examples of the metal hydroxide that can be used in the step (4) include caustic soda (sodium hydroxide), potassium hydroxide, and the like. However, the present invention is not limited thereto. Can be used. The amount of the metal hydroxide to be used in the step (4) is not particularly limited. For example, the amount of the metal hydroxide may be 0.1 to 5 parts by weight (more preferably 0.5 to 2 parts by weight) relative to 100 parts by weight of the sum of the branched monocarboxylic acid and epichlorohydrin, Parts by weight of metal hydroxide may be used.

The temperature condition in the step (4) is preferably 60 to 100 ° C, more preferably 65 to 95 ° C. In addition, the metal hydroxide may be added to the result of the step (4) to the step (3), followed by stirring for 1 to 3 hours. Further, an appropriate amount of water may be added for separation of the layers after the stirring.

The result of the completion of the epoxycyclohexylation reaction and the removal of the unreacted epichlorohydrin contains a significant amount (e.g., about 10,000 ppm) of hydrolyzed chlorine, and other minor amounts of side products. When hydrolyzed chlorine and a small amount of minor reactants remain, corrosion resistance and water resistance may be deteriorated when the diluent of the present invention is applied to the coating material applied to the metal adherend. In addition, the above-described decrease in purity and side effects may occur have. In the present invention, the cyclization reaction of residual hydrolyzable chlorine is further promoted through the step (4), and the minor residual reactants are over-reacted to precipitate in a solid phase and can be easily removed.

In the step (5) of the method for producing a branched monocarboxylic acid-modified epoxy reactive diluent of the present invention, the nonpolar organic solvent and water are added to the organic layer collected as a result of the step (4) and stirred, The organic layer is collected, and the non-polar organic solvent is removed therefrom.

As the nonpolar organic solvent, a nonpolar aliphatic or aromatic organic solvent which is commonly used in this technical field may be used, and more specifically, toluene, xylene, methylisobutylketone, and mixtures thereof may be used.

The amount of the nonpolar organic solvent to be used in the step (5) is not particularly limited. For example, the amount of the nonpolar organic solvent may be 5 to 50 parts by weight (more preferably 10 to 30 parts by weight per 100 parts by weight of the sum of the branched monocarboxylic acid and epichlorohydrin, By weight) of nonpolar organic solvent may be used. There is no particular limitation on the amount of water to be used. For example, 10 to 50 parts by weight (more preferably 15 to 30 parts by weight) of water may be used based on 100 parts by weight of the sum of the branched monocarboxylic acid and epichlorohydrin as reactants have.

Preferably, in step (5), an additional acid may be added to the organic layer in step (4). The acid added further removes and precipitates ionic impurities from the organic layer in the step (4). The acid usable in the step (5) may be an organic acid, an inorganic acid or a combination thereof. More specifically, acetic acid, phosphoric acid, and a combination thereof may be used. There is no particular limitation on the amount of the acid to be used. For example, 0.01 to 2 parts by weight (more preferably 0.02 to 0.5 part by weight) of an acid may be used based on 100 parts by weight of the sum of the branched monocarboxylic acid and epichlorohydrin as reactants have.

In the step (5), the temperature condition of the step of introducing the nonpolar organic solvent and the water into the organic layer in the step (4) and stirring the mixture is preferably 60 to 100 ° C, more preferably 65 to 95 ° C Do. The removal of the nonpolar organic solvent from the upper organic layer collected after the layer separation may be performed under elevated temperature and reduced pressure conditions. Specifically, the removal may be performed at a temperature of 110 to 150 ° C (more specifically, 120 to 140 ° C) (E.g., 10 to 100 torr).

In step (4), ionic impurities remain in the resultant product. If such ionic impurities remain in the final product, a branched monocarboxylic acid-modified epoxy-reactive diluent, similar to the case of hydrolyzable chlorine residues There may be a problem of deterioration of rustproofing property and water resistance when applying a paint. These ionic impurities can not be easily removed by conventional filtration or the like. In the present invention, the ionic impurities can be effectively removed through the step (5). The ionic impurities exhibit hydrophilic and water-soluble properties and can be easily removed using properties that are not compatible with non-polar materials. Accordingly, by adding a certain amount of a nonpolar solvent having compatibility to the mixture containing the branched monocarboxylic acid-modified epoxy reactive diluent obtained as a result of the above step (4), a mixture of the branched monocarboxylic acid-modified epoxy reactive diluent and the nonpolar solvent By maximizing the non-polarity of the system, the ionic impurities in the mixture are discharged to the outside of the mixture system, and the discharged ionic impurities are also water-soluble, coagulated and precipitated due to the addition of water and a small amount of organic acid and inorganic acid. When the mixture is allowed to stand in an agitation-stopping state, phase separation occurs between the organic layer, which is a mixture of the branched monocarboxylic acid-modified epoxy reactive diluent and the nonpolar solvent, and the aqueous layer containing the ionic impurities. By removing the aqueous layer containing the ionic impurities, Ionic impurities can be removed.

Hereinafter, the present invention will be described more specifically by way of examples. However, the following examples are intended to assist the understanding of the present invention, and the scope of the present invention is not limited to the examples in any sense.

[ Example ]

Example  One

(1) 384 g of neodecanoic acid and 618.8 g of epichlorohydrin were charged into a 2-liter flask equipped with a stirrer, a thermometer, a nitrogen inlet tube, a reflux condenser and a condenser, Respectively. After the completion of the heating, 9.6 g of a 50% aqueous solution of tetramethylammonium chloride was added, the mixture was heated to 80 to 90 ° C by natural heating, and then maintained for 2 ± 0.5 hours.

(2) Thereafter, 178.4 g of a 50% aqueous solution of caustic soda was homogeneously introduced for 2 ± 0.5 hours while the reactor temperature was maintained at 63 ± 2 ° C and the inside of the reactor was reduced to 150 ± 30 torr, The epoxy cyclization reaction was carried out. The effluent from the reflux tube during the reaction was separated into water and epichlorohydrin through phase separation and the collected epichlorohydrin was re-introduced into the reaction vessel.

(3) After the addition of caustic soda 50% aqueous solution was completed, the temperature was raised to 125 ± 5 ℃ under reduced pressure, and after the temperature was raised to 125 ± 5 ℃, the decompression degree was gradually increased to reduce the residual epichlorohydrin to less than 10 torr. Respectively.

(4) After completion of the removal of epichlorohydrin, the resultant was cooled to 90 ± 5 ° C, and 14.7 g of water and 17.3 g of 50% caustic soda aqueous solution were added, followed by holding for 80 ± 20 minutes. Thereafter, 460 g of water was added and stirred at 70 賊 5 째 C for 30 minutes to dissolve the salt generated during the reaction. After that, the contents were transferred to a separating funnel and kept for 30 minutes to phase-separate into an upper organic layer and a lower brine layer, and the lower brine layer was removed.

(5) The upper organic layer was transferred to a flask, and then 125 g of toluene, 270 g of water and 0.5 g of phosphoric acid were added thereto. The mixture was kept at 70 ± 5 ° C. for 30 minutes with stirring. The contents were transferred to a separatory funnel, . After removing the lower aqueous layer in the same manner as described above, the upper organic layer was transferred to a flask, and the temperature was raised to 130 ° C to remove the toluene first. Then, the toluene was removed under a reduced pressure of less than 100 torr to remove the toluene, thereby obtaining a branched monocarboxylic acid denatured reactive epoxy diluent .

The epoxy equivalence (EEW) of the branched monocarboxylic acid-modified reactive epoxy diluent thus prepared was 240.7 g / eq and the hydrolyzable chlorine content was 112 ppm.

Comparative Example  One

Except that 178.4 g of a 50% aqueous solution of caustic soda was added for 2 ± 0.5 hours while the condensation water was not removed by depressurization, the same procedure as in Example 1 was carried out to obtain a branched monocarboxylic acid denatured reactive epoxy diluent . The epoxy equivalent (EEW) of the resultant product was 288.7 g / eq, and the hydrolyzable chlorine content was 212 ppm.

Comparative Example  2

14.7 g of water and 17.3 g of 50% caustic soda aqueous solution were added in the step (4) of Example 1, and the process of maintaining the temperature for 80 ± 20 minutes was not carried out, and the subsequent step was carried out in the same manner as in Example 1 , A branched monocarboxylic acid-modified reactive epoxy diluent was prepared. The epoxy equivalent (EEW) of the resultant product was 240.3 g / eq, and the hydrolyzable chlorine content was 11,052 ppm.

Claims (10)

(1) addition reaction of a branched monocarboxylic acid and epichlorohydrin in the presence of a catalyst;
(2) performing epoxycyclohexylation reaction of the resultant addition product of step (1) while azeotropically boiling water and epichlorohydrin and refluxing epichlorohydrin under the presence of metal hydroxide and under reduced pressure;
(3) removing unreacted epichlorohydrin from the resulting mixture of step (2);
(4) adding metal hydroxide to the result of step (3), stirring, and then separating the upper organic layer; And
(5) adding a nonpolar organic solvent and water to the organic layer collected as a result of the step (4) and stirring the mixture, separating the organic layer to collect the upper organic layer, and removing the nonpolar organic solvent therefrom.
A process for producing a branched monocarboxylic acid-modified epoxy reactive diluent. The process for producing a branched monocarboxylic acid-modified epoxy reactive diluent according to claim 1, wherein the branched monocarboxylic acid is a branched alkanoic monocarboxylic acid having 3 to 20 carbon atoms. The method of claim 1, wherein the metal hydroxide is caustic soda. The method according to claim 1, wherein the reaction of step (2) is carried out under a pressure of 100 to 200 torr. The process according to claim 1, wherein the reaction of step (2) is carried out at a temperature of 50 to 70 ° C. The method according to claim 1, wherein in step (4), the metal hydroxide is used in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the total of the branched monocarboxylic acid and epichlorohydrin. A process for producing a monocarboxylic acid modified epoxy reactive diluent. The process for preparing a branched monocarboxylic acid-modified epoxy reactive diluent according to claim 1, wherein the step (4) is carried out at a temperature of 60 to 100 ° C. The process according to claim 1, wherein the non-polar organic solvent used in step (5) is selected from toluene, xylene, methyl isobutyl ketone, and mixtures thereof. Way. The process for producing a branched monocarboxylic acid-modified epoxy reactive diluent according to claim 1, wherein an acid is further added in the step (5). 10. The method of claim 9, wherein the acid is selected from acetic acid, phosphoric acid, and combinations thereof.