Preparation method of sulfydryl inverse ester

Abstract

The invention discloses a preparation method of sulfydryl reverse ester, and relates to the field of fine chemical engineering. The invention relates to a sulfydryl inverse ester preparation method, which comprises: carrying out a reaction 1 on an esterification reaction raw material, a solid superacid anion resin catalyst and / or an antioxidant to obtain a reaction 1 mixture; vacuumizing the reaction 1 mixture, and drying and dehydrating; and cooling the vacuum pipeline, carrying out a reaction 2, and cooling and filtering to obtain the mercapto inverse ester. The sulfydryl reverse ester product prepared by the preparation method is high in purity and low in production cost.

Description

Technical Field

[0001] The invention relates to the field of fine chemicals, and in particular to a method for preparing a mercapto reverse ester. Background Art

[0002] Mercapto reverse ester is a key intermediate for the synthesis of reverse ester methyltin mercaptide. It is widely used in various polymer materials such as thermal transparent sheets, pipes, and fittings due to its wide range of raw material sources, low tin content, and relatively low price compared to traditional methyltin mercaptide. As an important organic tin stabilizer, reverse ester methyltin mercaptide has excellent thermal stability and processing properties, and can significantly improve the heat resistance and mechanical strength of polymer materials.

[0003] The traditional synthesis method of mercapto reverse ester mainly relies on strong acid catalysts such as concentrated sulfuric acid, methanesulfonic acid, and toluenesulfonic acid. Although these catalysts can effectively promote the esterification reaction, they have serious corrosion effects on reaction equipment, vacuum pipelines, etc. during use. As a strong oxidizing acid, concentrated sulfuric acid is easy to cause side reactions, leading to oxidation or polymerization of sulfhydryl groups, thereby deepening the color of the product mercapto reverse ester, and reducing purity and yield. In addition, methanesulfonic acid and toluenesulfonic acid are difficult to completely remove after the reaction is completed, and remain in the mercapto reverse ester, resulting in the final produced reverse ester type methyltin mercaptan product being easy to precipitate.

[0004] In order to solve these problems, the conventional refining method usually adopts water washing, drying and distillation to purify the crude mercapto reverse ester. However, this method not only requires the addition of additional equipment, pipelines and instruments, but also produces a large amount of waste water and consumes a large amount of energy. In addition, due to the loss during the purification process, the yield of mercapto reverse ester will be reduced, thereby significantly increasing the production cost.

[0005] In summary, the existing methods for synthesizing mercapto reverse esters have a series of problems such as catalyst corrosion of equipment, induction of side reactions, low product purity, reduced yield, and complex purification process and high cost. Summary of the invention

[0006] The purpose of the present invention is to overcome the above technical deficiencies, provide a method for preparing a mercapto reverse ester, and solve the problems of low purity and high cost of mercapto reverse ester products in the prior art.

[0007] In order to achieve the above technical purpose, the technical solution of the present invention provides a method for preparing a mercapto reverse ester, comprising the following steps:

[0008] S1, reacting the esterification reaction raw materials, the solid superacid anion resin catalyst and / or the antioxidant to obtain a reaction mixture;

[0009] S2, vacuumizing the reaction mixture to dry and dehydrate;

[0010] S3, cooling the vacuum pipeline, carrying out reaction 2, and obtaining the mercapto reverse ester by cooling and filtering.

[0011] Preferably, the esterification reaction raw materials in S1 include mercaptoethanol and an organic acid.

[0012] Preferably, the organic acid is one or more of oleic acid, isooctanoic acid, lauric acid, stearic acid, n-butyric acid, and pivalic acid.

[0013] Preferably, the mass ratio of the mercaptoethanol to the organic acid is 0.3-1.479:1.

[0014] Preferably, the solid superacid anion resin catalyst has a feed mass of 0.8-2% of the organic acid, and the antioxidant has a feed mass of 0.5-1.2% of the organic acid. The antioxidant can be β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate.

[0015] Preferably, the reaction temperature of reaction 1 in S1 is 50-65° C., and the reaction time is 1-2 hours.

[0016] Preferably, the drying and dehydration in S2 is carried out at a temperature of 65-75° C. and for 3-6 hours.

[0017] Preferably, the reaction temperature of reaction 2 in S3 is 75-90° C., and the reaction time is 1-2 hours.

[0018] In the method of the present invention, the first step is to carry out a normal pressure heat preservation reaction on the esterification reaction raw materials, the solid superacid anion resin catalyst and the antioxidant; the second step is to carry out a reduced pressure drying dehydration reaction on the reaction synthesis liquid; the third step is to carry out a negative pressure heat preservation on the synthesis reaction liquid after the dehydration reaction is completed; the fourth step is to cool the reaction liquid and filter and recover the solid superacid anion resin catalyst to obtain a light yellow-green clear and transparent liquid, namely, a mercapto reverse ester. The mercapto reverse ester synthesized by using the solid superacid anion resin catalyst can reduce the equipment and instrument costs, reduce equipment corrosion, reduce the amount of wastewater generated and environmental pollution, reduce production energy consumption, increase the purity of the mercapto reverse ester and reduce the color number compared with the traditional method for synthesizing mercapto reverse ester (the catalyst uses concentrated sulfuric acid, toluenesulfonic acid, methanesulfonic acid, etc.).

[0019] The solid superacid anion resin catalyst is composed of a skeleton part, active groups and exchangeable ions. Skeleton part: It is composed of styrene polymers, such as copolymers of styrene and divinylbenzene, in which divinylbenzene plays a cross-linking role to form a stable three-dimensional network structure, which provides mechanical strength and stability for the catalyst. Active groups: Mainly sulfonic acid groups (-SO H), which are the key groups that make the resin strongly acidic, can provide acidic catalytic active centers, play an important role in catalytic reactions, and can reduce the activation energy of the reaction through processes such as proton transfer between the reactants, thereby promoting the reaction. Exchangeable ions: Generally hydrogen ions (H+), which can be exchanged with cations in the reactants and then participate in the catalytic reaction process.

[0020] Compared with the prior art, the beneficial effects of the present invention include:

[0021] Solid superacid anion resin catalyst has extremely high acid strength and high catalytic activity, which can significantly increase the rate of esterification reaction, thereby increasing the yield of mercapto reverse ester. Compared with traditional strong acid catalysts such as concentrated sulfuric acid, solid superacid anion resin catalyst has better selectivity, can reduce the occurrence of side reactions, and improve the purity of the main product. In addition, the catalyst is in solid form and can be separated from the reaction mixture by simple filtration after the reaction is completed, avoiding the problem of catalyst residue and reducing production costs.

[0022] The addition of antioxidants can effectively inhibit the oxidation of acid catalysts, reduce the oxidation or polymerization of mercaptoethanol, and thus improve the purity and yield of mercapto reverse esters. The addition of antioxidants can prevent the color of the product from deepening and ensure the quality of mercapto reverse esters. The use of antioxidants and vacuum operation effectively reduce the occurrence of side reactions and ensure the purity of the main product. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] This embodiment provides a method for preparing a mercapto reverse ester, comprising the following steps:

[0025] S1, reacting mercaptoethanol, oleic acid, a solid superacid anion resin catalyst and β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester 1, the reaction temperature is 50° C., the reaction time is 2 hours, to obtain a reaction 1 mixture, the mass ratio of the mercaptoethanol to the organic acid is 0.30:1, the feed mass of the solid superacid anion resin catalyst is 0.8% of the organic acid, and the feed mass of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester is 0.5% by weight of the organic acid;

[0026] S2, vacuum drying the reaction mixture at 65° C. for 3 hours;

[0027] S3. After the vacuum pipeline is completely cooled, the temperature is raised to 75° C. to carry out reaction 2 for 1 hour. After cooling and filtering, the mercapto reverse ester is obtained, and the solid superacid anion resin catalyst is recovered.

[0028] The sulfur content of the mercapto reverse ester sample was detected to be 8.52%, the acid value was 2.32 mgKOH / g, and the yield was 91.03% based on the acid.

[0029] Example 2

[0030] This embodiment provides a method for preparing a mercapto reverse ester, comprising the following steps:

[0031] S1, mercaptoethanol, isooctanoic acid, a solid superacid anion resin catalyst and β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate are reacted 1, the reaction temperature is 65° C., the reaction time is 1 hour, and a reaction mixture 1 is obtained, wherein the mass ratio of the mercaptoethanol to the organic acid is 0.65:1, the feed mass of the solid superacid anion resin catalyst is 2% of the organic acid, and the feed mass of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate is 1.2% of the organic acid;

[0032] S2, vacuum drying the reaction mixture at 75° C. for 6 hours;

[0033] S3. After the vacuum pipeline is completely cooled, the temperature is raised to 90° C. to carry out reaction 2 for 2 hours. The mercapto reverse ester is obtained by cooling and filtering.

[0034] The sulfur content of the mercapto reverse ester sample was detected to be 15.78%, the acid value was 2.15 mgKOH / g, and the yield was 99.37% based on the acid.

[0035] Example 3

[0036] This embodiment provides a method for preparing a mercapto reverse ester, comprising the following steps:

[0037] S1, reacting mercaptoethanol, lauric acid, a solid superacid anion resin catalyst and β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester 1, the reaction temperature is 60° C., the reaction time is 1.5 hours, and a reaction mixture 1 is obtained, the mass ratio of the mercaptoethanol to the organic acid is 0.429:1, the feed mass of the solid superacid anion resin catalyst is 1% of the organic acid, and the feed mass of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester is 1% of the organic acid;

[0038] S2, vacuum drying the reaction mixture at 68° C. for 4 hours;

[0039] S3. After the vacuum pipeline is completely cooled, the temperature is raised to 80° C. to carry out reaction 2 for 1.5 hours. After cooling and filtering, the mercapto reverse ester is obtained.

[0040] The sulfur content of the mercapto reverse ester sample was detected to be 12.22%, the acid value was 3.24 mgKOH / g, and the yield was 99.27% ​​based on the acid.

[0041] Example 4

[0042] This embodiment provides a method for preparing a mercapto reverse ester, comprising the following steps:

[0043] S1, reacting mercaptoethanol, stearic acid, a solid superacid anion resin catalyst and β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester 1, the reaction temperature is 65° C., the reaction time is 2 hours, and a reaction mixture 1 is obtained, wherein the mass ratio of the mercaptoethanol to the organic acid is 0.3296:1, the feed mass of the solid superacid anion resin catalyst is 1% of the organic acid, and the feed mass of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester is 1% of the organic acid;

[0044] S2, vacuum drying the reaction mixture at 75° C. for 4 hours;

[0045] S3. After the vacuum pipeline is completely cooled, the temperature is raised to 80° C. to carry out reaction 2 for 1 hour. After cooling and filtering, the mercapto reverse ester is obtained.

[0046] The sulfur content of the mercapto reverse ester sample was detected to be 9.05%, the acid value was 3.18 mgKOH / g, and the yield was 97.31% based on the acid.

[0047] Example 5

[0048] This embodiment provides a method for preparing a mercapto reverse ester, comprising the following steps:

[0049] S1, reacting mercaptoethanol, n-butyric acid, a solid superacid anion resin catalyst and β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester 1 to obtain a reaction 1 mixture, wherein the mass ratio of the mercaptoethanol to the organic acid is 1.479:1, the feed mass of the solid superacid anion resin catalyst is 1% of the organic acid, and the feed mass of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester is 1% of the organic acid;

[0050] S2, vacuum drying the reaction mixture at 70° C. for 5 hours;

[0051] S3. After the vacuum pipeline is completely cooled, the temperature is raised to 80° C. to carry out reaction 2 for 1 hour. After cooling and filtering, the mercapto reverse ester is obtained.

[0052] The sulfur content of the mercapto reverse ester sample was detected to be 26.95%, the acid value was 2.79 mgKOH / g, and the yield was 99.37% based on the acid.

[0053] Example 6

[0054] This embodiment provides a method for preparing a mercapto reverse ester, comprising the following steps:

[0055] S1, reacting mercaptoethanol, pivalic acid, a solid superacid anion resin catalyst and β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester 1 to obtain a reaction 1 mixture, wherein the mass ratio of the mercaptoethanol to the organic acid is 0.841:1, the feed mass of the solid superacid anion resin catalyst is 1% of the organic acid, and the feed mass of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester is 0.6% of the organic acid;

[0056] S2, vacuum drying the reaction mixture at 75° C. for 6 hours;

[0057] S3. After the vacuum pipeline is completely cooled, the temperature is raised to 90° C. to carry out reaction 2 for 2 hours. The mercapto reverse ester is obtained by cooling and filtering.

[0058] The sulfur content of the mercapto reverse ester sample was detected to be 19.58%, the acid value was 2.93 mgKOH / g, and the yield was calculated to be 99.14%.

[0059] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a mercapto reverse ester, characterized in that: The following steps are involved: S1, reacting the esterification reaction raw materials, the solid superacid anion resin catalyst and / or the antioxidant to obtain a reaction mixture; S2, vacuumizing the reaction mixture to dry and dehydrate; S3, cooling the vacuum pipeline, carrying out reaction 2, and obtaining the mercapto reverse ester by cooling and filtering.

2. The method for preparing a mercapto reverse ester according to claim 1, wherein The esterification reaction raw materials in S1 include mercaptoethanol and an organic acid.

3. The method for preparing a mercapto reverse ester according to claim 2, wherein The organic acid is one or more of oleic acid, isooctanoic acid, lauric acid, stearic acid, n-butyric acid and pivalic acid.

4. The method for preparing a mercapto reverse ester according to claim 3, wherein The mass ratio of the mercaptoethanol to the organic acid is 0.3-1.479:

1.

5. The method for preparing a mercapto reverse ester according to claim 4, wherein The feed weight of the solid superacid anion resin catalyst is 0.8-2% of the organic acid, and the feed weight of the antioxidant is 0.5-1.2% of the organic acid.

6. The method for preparing a mercapto reverse ester according to claim 1, wherein The reaction temperature of reaction 1 in S1 is 50-65°C, and the reaction time is 1-2 hours.

7. The method for preparing a mercapto reverse ester according to claim 1, wherein The drying and dehydration in S2 is carried out at a temperature of 65-75° C. for 3-6 hours.

8. The method for preparing a mercapto reverse ester according to claim 1, wherein The reaction temperature of reaction 2 in S3 is 75-90° C., and the reaction time is 1-2 hours.