RU2486210C1 - Method of producing epoxidated 1,2-polybutadienes - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: present invention relates to production of polymer products based on 1,2-polybutadienes, which contain epoxide groups in macromolecules. Described is a method of producing epoxidated 1,2-polybutadienes, involving reaction of a polymer solution in an organic solvent with an epoxidation agent containing hydrogen peroxide, characterised by that sodium molybdate and phosphoric acid are further added to the epoxidation agent, and epoxidated 1,2-polybutadienes are obtained in the presence of a phase transfer catalyst - cetylpyridinium chloride, wherein the molar ratio 1,2-polybutadiene:hydrogen peroxide is equal to 1:0.4-1.1; 1,2-polybutadiene:sodium molybdate is equal to 1:0.07-0.5; 1,2-polybutadiene:phosphoric acid is equal to 1:0.08-0.7; 1,2-polybutadiene:cetylpyridinium chloride is equal to 1: 0.22; reactants react at temperature of 50-55°C for 3 hours; pH of the reaction medium is kept at 2-3 by adding 0.1 M aqueous sodium hydrophosphate solution.

EFFECT: improved quality of the end product, low power consumption.

1 tbl, 14 ex

Description

The invention relates to the field of macromolecular compounds, in particular to the production of polymer products based on 1,2-polybutadiene containing epoxy groups in the composition of macromolecules.

Epoxidized polymer products are characterized by a high complex of physical and mechanical properties, good adhesive properties and can be used in adhesive compositions, sealants, paints, and as modifiers in various compositions of thermoplastics and elastomers.

Epoxidized 1,2-polybutadiene can be obtained by chemical modification of 1,2-polybutadiene containing double carbon-carbon bonds in macromolecules of the main and side chains, which are synthesized in industry by polymerization of 1,3-butadiene on complex catalysts [RF Patent 2072362, cl. C08F 136/06, C08F 36/06, C08F 136/00, C08F 36/00; publ. 01/27/1997. RF patent 2177008, cl. C08F 136/06, C08F 36/06, C08F 36/04, C08F 4/70; publ. 12/20/2001. RF patent 2283850, cl. C08F 36/06, C08F 136/06; publ. 09/20/2006. U.S. Patent 4,182,813, CL C08F 136/06, C08F 36/00, C08F 4/00; publ. 01/08/1980. RF patent 2139299, cl. C08F 136/06; publ. 10/10/1999].

The method of producing epoxidized 1,2-polybutadiene is based on the interaction of 1,2-polybutadiene with an epoxidizing agent, which is used as molybdenum peroxo complexes. The most widely used method of epoxidation of 1,2-polybutadiene, in which the peroxocomplex is generated directly in the reaction flask by the interaction of an aqueous solution of hydrogen peroxide with sodium molybdate in the presence of phosphoric acid and an interphase catalyst.

A known method for producing epoxy-modified atactic 1,2-polybutadiene by monoperphthalic acid [Wen-Kuei Huang, Ging-Ho Hsiue, Wei-Hsin Hou. Epoxidation of polybutadiene and styrene-butadiene triblock copolymers with monoperoxyphthalic acid: Kinetic and conformation study, Journal of Polymer Science Part A: Polymer Chemistry, V.26, (7). p. 1867-1883, 1988]. The disadvantages of this method include the allocation during the reaction of phthalic acid formed from monoperphthalic acid, and the need to filter the reaction mixture.

A known method of epoxidation of 1,2-polybutadiene by the action of meta-chloroperbenzoic acid in toluene, benzene, methylene chloride [US Patent 5034471, cl. C08F 136/06, C08F 36/00, C08F 4/00; publ. 07/23/1991]. To a solution of 1,2-polybutadiene in methylene chloride, meta-chloroperbenzoic acid is added but dropwise at a molar ratio of 1,2-PB: acid = 1: 1, at a temperature. The reaction mass is a suspension, where meta-chlorobenzoic acid, formed during the process, is released into the solid phase. After 4 hours, the reaction mixture was cooled to -15 ° C and filtered. The cooling and filtration procedures are repeated until solid impurities disappear in the filtrate. This method allows to obtain modified polymer products with an epoxidation degree of up to 90%.

The disadvantages of this method include the high cost of the used epoxidizing agent, the need to filter the reaction mass at low temperatures. The disadvantage of this method is the complexity of the process, requiring repeated filtering of the reaction mass. In addition, the use of meta-chloroperbenzoic acid as an epoxidizing agent leads to secondary reactions of the opening of oxirane groups.

The closest to the invention in technical essence and the achieved effect is a method for producing epoxidized syndiotactic 1,2-polybutadiene, which consists in the interaction of a solution of 1,2-polybutadiene in an organic solvent (toluene, benzene, chloroform) with an epoxidizing agent, which is used as a mixture of peroxide hydrogen and carboxylic acids containing from 1 to 10 carbon atoms [US Patent 4,528,340, cl. C08C 19/06; C08G 59/16; C08C 19/00; C08G 59/00; publ. 07/09/1985]. The molar ratio of polymer: carboxylic acid: hydrogen peroxide is 1: 0.3-1: 0.5-1.5. The consumption of carboxylic acid is 0.01-5 mol, hydrogen peroxide from 0.1 to 5 mol per 100 g of polymer. A polymer solution in an organic solvent is preliminarily prepared. The reaction is carried out at a temperature of from 5 to 90 ° C, gradually dosing for 20 minutes a solution of carboxylic acid and 30% aqueous hydrogen peroxide solution to the polymer solution with vigorous stirring for 5-8 hours. The resulting reaction mass is washed with distilled water, the polymer reprecipitated from the organic phase with methyl alcohol. The degree of functionalization (conversion of unsaturated units to epoxy groups) of syndiotactic 1,2-polybutadiene is 5-60%.

The disadvantages of this method are the high energy costs due to the need to carry out the process at elevated temperatures (up to 90 ° C) and for a long time the possibility of adverse reactions associated with the opening of epoxy groups in the modified polymer.

The technical task of this invention is to develop a method for producing epoxidized 1,2-polybutadiene, which improves the quality of the target product, reduces energy costs.

In the proposed method for producing epoxidized 1,2-polybutadiene, this technical problem is achieved by the interaction of a solution of 1,2-polybutadiene in an organic solvent with an epoxidizing agent. As an epoxidizing agent, a mixture of hydrogen peroxide, phosphoric acid and sodium molybdate is used in the presence of an interfacial catalyst cetylpyridinium chloride. The interaction of the reagents is carried out at a molar ratio of 1,2-polybutadiene: hydrogen peroxide = 1: 0.4-1.1; 1,2-polybutadiene: sodium molybdate = 1: 0.07-0.5; 1,2-polybutadiene: phosphoric acid = 1: 0.08-0.7; 1,2-polybutadiene: cetylpyridinium chloride = 1: 0.22 at a temperature of 55 ° C for 2-3 hours. The pH of the aqueous medium 2-3 was maintained by introducing a 0.1 M aqueous solution of sodium hydrogen phosphate. As the starting 1,2-polybutadiene, an atactic or syndiotactic polymer with a number average molecular weight M _n from 1000 to 150,000 and a content of 1,2- and 1,4-polymerization units in the macromolecules of 70-85 mol% and 15-30 mol. %, respectively.

When implementing the proposed method used industrial samples of 1,2-polybutadiene produced by JSC "Ephraim Plant SK" and polymers of the brand JSR RB produced by "Japan Synthetic Rubber Co." (Japan). A 1,2-polybutadiene sample was purified by reprecipitation in the chloroform-ethanol system, then the polymer was washed twice with alcohol and dried under vacuum at 60 ° C to constant weight. As the starting components of the epoxidizing agent, a 30-40% hydrogen peroxide solution was used in accordance with GOST 177-88 grade A, sodium molybdate in accordance with GOST 18289-78, phosphoric acid in accordance with GOST 10678-76.

The invention is illustrated by the following examples.

Example 1. Used purified syndiotactic 1,2-polybutadiene with a number average molecular weight M _n = 150,000, containing 1,2- and 1,4-polymerization units of 86 and 14 mol%, respectively. 3 g (0.056 mol) of 1,2-polybutadiene were charged into a glass reactor equipped with a stirrer, reflux condenser and dropping funnel. 114.3 ml of toluene was added and mixed until completely dissolved. 1.15 g of sodium molybdate (0.0056 mol), 1.68 g of 98% phosphoric acid (0.0168 mol), 3.6 g of a 37% hydrogen peroxide solution (0.0392 mol) were added to the resulting solution. ) and 4.2 g of cetylpyridinium chloride (0.0123 mol). The molar ratio of polymer: hydrogen peroxide = 1: 0.7; polymer: sodium molybdate = 1: 0.1; polymer: phosphoric acid = 1: 0.3; polymer: cetylpyridinium chloride = 1: 0.22. The pH of the aqueous medium 2-3 was maintained by introducing a 0.1 M aqueous solution of sodium hydrogen phosphate. The reaction mass was stirred at 55 ° C for 2-3 hours. After the synthesis was completed, the organic phase was washed with distilled water until pH 7 was reached. The polymer was precipitated from the reaction mass with ethanol, purified by reprecipitation in the chloroform-ethanol system, and dried in vacuum at 40 ° C. . Received 2.67 g of epoxidized syndiotactic 1,2-polybutadiene with a degree of functionalization of 26.1%. In the IR spectrum of the modified epoxidized syndiotactic 1,2-polybutadiene there are no signals in the region of 3000-3600 cm ^-1 characteristic of hydroxyl groups. This allows us to conclude that during epoxidation, no side reactions of the opening of epoxy groups occurred.

Example 2. In a glass reactor equipped with a stirrer, reflux condenser and dropping funnel, 3 g (0.055 mol) of 1,2-polybutadiene were charged, 114.3 ml of toluene was added and stirred until complete dissolution. 1.15 g of sodium molybdate (0.0056 mol), 1.68 g of 98% phosphoric acid (0.0168 mol), 3.6 g of a 37% hydrogen peroxide solution (0.0392 mol) were added to the resulting solution. ) and 4.2 g of cetylpyridinium chloride (0.0123 mol). The molar ratio of polymer: hydrogen peroxide = 1: 0.7; polymer: sodium molybdate = 1: 0.1; polymer: phosphoric acid = 1: 0.3; polymer: cetylpyridinium chloride = 1: 0.22. The pH of the aqueous medium 2-3 was maintained by introducing a 0.1 M aqueous solution of sodium hydrogen phosphate. The reaction mass was stirred at 55 ° C for 2-3 hours. After the synthesis was completed, the organic phase was washed with distilled water until pH 7 was reached. The polymer was precipitated from the reaction mass with ethanol, purified by reprecipitation in the chloroform-ethanol system, and dried in vacuum at 40 ° C. . Received 2.72 g of epoxidized syndiotactic 1,2-polybutadiene with a degree of functionalization of 31.1%. In the IR spectrum of the modified epoxidized syndiotactic 1,2-polybutadiene there are no signals in the region of 3000-3600 cm ^-1 characteristic of hydroxyl groups. This allows us to conclude that during epoxidation, no side reactions of the opening of epoxy groups occurred.

The mass fraction of epoxy groups in the polymer was determined by the following procedure [Jay, RR Direct Titration of Erohu Compounds and Aziridines, Anal. Chem., 1964, 36 (3): 667-668]: the calculated amount of HClO ₄ solution was added to the solution of the analyzed sample in toluene and stirred for 2 hours. Then phenolphthalein was added to the solution and titrated with an aqueous solution of sodium hydroxide. The degree of epoxidation is calculated by the formula:

, $$\mathrm{FROM}tePenb\mathrm{uh}P\mathrm{about}\mathrm{to}\mathrm{from}\mathrm{and}d\mathrm{and}R\mathrm{about}\mathrm{at}\mathrm{but}n\mathrm{and}\mathrm{I\; am}=\frac{\left(V_{\mathrm{one}}-V_0\right)\cdot N\cdot 70}{10\cdot w}$$

,

where V ₀ and V ₁ are the volumes of the HClO ₄ solution (ml) spent on titration for the blank and analyzed samples, respectively; w - sample weight (g); N is the molar concentration of the HClO ₄ solution (mol / L); 70 - molecular weight of epoxidized butadiene units.

Examples 3-14. All operations were carried out in accordance with example 1. The experimental results are shown in the table.

The molar ratio polymer: hydrogen peroxide = 1: 0.7 seems to be the most optimal (experiment 1-2). With an increase in the concentration of hydrogen peroxide, its non-productive decomposition accelerates more and the quality of the target product deteriorates due to the crosslinking of polymer macrochains (experiment 3). Maintaining the concentration of hydrogen peroxide in the reaction medium below the required value does not allow to achieve the desired degree of epoxidation of the final product (experiment 4). The molar ratio of polymer: sodium molybdate = 1: 0.1. With an increase in the concentration of sodium molybdate, turbidity of the aqueous phase is observed (experiment 5), and a decrease in concentration leads to a decrease in the degree of epoxidation (experiment 6). A decrease in the concentration of phosphoric acid in the reaction mass leads to a decrease in the degree of functionalization of the final product (experiment 7). An increase in the concentration of phosphoric acid causes the hydrolysis of epoxy groups and the gelation of polydiene (experiment 8). The temperature range of 50-55 ° C allows to obtain modified products with the highest yield and with minimal unproductive decomposition of hydrogen peroxide. At temperatures above 55 ° C, the non-productive decomposition of hydrogen peroxide increases and product gelation occurs (experiment 9), and at temperatures below 50 ° C the epoxidation rate decreases and the yield of the target product decreases (experiment 10). A significant influence on the quality of the product has a pH of the aqueous medium. When the pH of the medium above 3 and below 2 decreases the degree of epoxidation of the target product (experiment 11-12). The pH of the reaction medium is maintained by introducing a special buffer system into the reaction medium. The interaction within 2.5 hours ensures the completeness of the process of epoxidation.

In the proposed method for producing epoxidized 1,2-polybutadiene, an aqueous solution of sodium molybdate, hydrogen peroxide and phosphoric acid is used as the epoxidizing agent. The epoxidation process is carried out at a temperature of 50-55 ° C for 2.5 hours, thereby reducing energy costs and eliminating the possibility of a side reaction of the disclosure of epoxy groups, which improves the quality of the target product.

Thus, the proposed method enables the targeted production of polymer products containing epoxy groups based on 1,2-polybutadiene with a given degree of functionalization (content of epoxy groups) from 3.9 to 32.4%, molecular weight 1000-150000 and content in macromolecules of 1,2-polymerization units 70-85 mol.% depending on the requirements for the polymer.

The results of experiments on the synthesis of epoxidized polybutadiene No. 1,2-PB Process conditions The degree of epoxidation,% Note the molar ratio of 1,2-PB: H ₂ O ₂ molar ratio of 1,2-PB: Na ₂ MoO ₄ molar ratio of 1.2-PB: H ₃ PO ₄ t ° C pH τ, h one from 1: 0.7 1: 0.1 1: 0.3 55 2,5 3 26.1 2 but 1: 0.7 1: 0.1 1: 0.3 55 2,5 3 31.1 3 A., p. 1: 1,1 1: 0.1 1: 0.3 55 2,5 3 ~ 7.1 gelation rm four A., p. 1: 0.4 1: 0.1 1: 0.3 55 2,5 3 14.7 decline in CE 5 A., p. 1: 0.7 1: 0.5 1: 0.3 55 2,5 3 26.5 6 A., p. 1: 0.7 1: 0.07 1: 0.3 55 2,5 3 15.9 decline in CE 7 A., p. 1: 0.7 1: 0.1 1: 0.7 55 2,5 3 ~ 3.3 gelation rm 8 A., p. 1: 0.7 1: 0.1 1: 0.08 55 2,5 3 17.3 decline in CE 9 A., p. 1: 0.7 1: 0.1 1: 0.3 45 2,5 3 22.0 decline in CE 10 A., p. 1: 0.7 1: 0.1 1: 0.3 60 2,5 3 18.8 partial city eleven A., p. 1: 0.7 1: 0.1 1: 0.3 55 four 3 > 7.2 decline in CE 12 A., p. 1: 0.7 1: 0.1 1: 0.3 55 1,5 3 14.2 partial city 13 A., p. 1: 0.7 1: 0.1 1: 0.3 55 2,5 6 ~ 9.4 gelation rm fourteen A., p. 1: 0.7 1: 0.1 1: 0.3 55 2,5 one 13.5 decline in CE S.E. - degree of epoxidation; m - reaction mass; g. - hydroxylation; but. - atactic 1,2-polybutadiene; from. - syndiotactic 1,2-polybutadiene

Claims (2)

1. The method of producing epoxidized 1,2-polybutadiene, which consists in the interaction of a polymer solution in an organic solvent with an epoxidizing agent, including hydrogen peroxide, characterized in that sodium molybdate and phosphoric acid are added to the epoxidizing agent, and the preparation of epoxidized 1,2-polybutadiene carried out in the presence of an interphase catalyst cetylpyridinium chloride, a molar ratio of 1,2-polybutadiene: hydrogen peroxide = 1: 0.4-1.1; 1,2-polybutadiene: sodium molybdate = 1: 0.07-0.5; 1,2-polybutadiene: phosphoric acid = 1: 0.08-0.7; 1,2-polybutadiene: cetylpyridinium chloride = 1: 0.22, the interaction of the reactants is carried out at a temperature of 50-55 ° C for 3 hours, the pH of the reaction medium 2-3 is maintained by introducing a 0.1 M aqueous solution of sodium hydrogen phosphate. 2. The method according to claim 1, characterized in that atactic or syndiotactic 1,2-polybutadiene is used with a number average molecular weight M _n from 1000 to 150,000 and a content of 1,2-polymerization units of 70-85 mol% in the macromolecules.