Thiodiglycolic acid ethylene ester and preparation method thereof

Abstract

The invention discloses a preparation method of ethidene thiodiglycolate, which is characterized by comprising the following steps: (1) mixing sodium sulfide and ethyl chloroacetate in a solvent for reaction; (2) after the reaction is finished, carrying out suction filtration, washing and drying to obtain a crude product; (3) purifying the crude product by utilizing high-temperature distillation to obtain high-purity thiodiglycolic acid ethylene ester; and (4) recovering and recycling the solvent and unreacted intermediate products. The barium chemical by-product sodium sulfide (the content of sodium sulfide is about 50%) is used as a reactant, so that the cyclic utilization of raw materials is realized, and the cost is reduced; by recycling the solvent and the intermediate product, the utilization efficiency of resources is improved, and the environmental pollution is reduced; the reaction conditions are optimized, and the yield and the purity of the thiodiglycolic acid ethanedioate are improved; the purification process is simplified, the production cost is reduced, and the economic benefit is improved.

Description

Technical Field

[0001] The invention relates to the field of organic synthesis, and in particular to a method for preparing ethylene thiodiglycolate. The method uses sodium sulfide, a byproduct of barium chemical industry, as a reactant and realizes the recycling of solvents and intermediate products to improve the conversion rate. Background Art

[0002] Ethylene Dithiocarbamate (EDTC), as a key organosulfur compound, plays a pivotal role in multiple industries. In the pharmaceutical field, it is used as a precursor for the synthesis of certain antibiotics and antifungal drugs; in the pesticide industry, it is an effective component of fungicides and insecticides; and in materials science, it is used to synthesize new materials due to its unique chemical properties. However, the traditional preparation method of EDTC not only has high raw material costs, but also generates a lot of environmental pollution during the production process, which runs counter to the current global pursuit of sustainable development and green chemistry.

[0003] In addition, the existing technology often fails to fully consider the effective utilization of by-products in the process of preparing EDTC, which not only causes a waste of resources, but also reduces the efficiency of the entire production process. In order to solve these problems, this technology proposes an innovative preparation method, which uses sodium sulfide, a by-product of the barite industry, as a reaction substrate. Sodium sulfide is produced in large quantities in the barite industry, but is usually treated as waste. This technology converts it into a valuable chemical raw material, which not only increases the economic value of sodium sulfide, but also realizes the recycling of resources. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing ethylene thiodiglycolate, which uses low-purity sodium sulfide, a by-product of barium chemical industry, as a key reactant, significantly improves the reaction conversion rate and the purity of the product by recycling solvents and intermediates, and reduces production costs and environmental pollution.

[0005] The invention has the beneficial effects of: a method for preparing ethylene thiodiglycolate, comprising the following steps: (1) mixing sodium sulfide and ethyl chloroacetate in a solvent to react; (2) after the reaction is completed, obtaining a crude product by suction filtration, washing and drying; (3) purifying the crude product by high-temperature distillation to obtain high-purity ethylene thiodiglycolate; and (4) recovering and recycling the solvent and unreacted intermediate products.

[0006] The sodium sulfide is a byproduct of barium chemical industry, and the content of sodium sulfide is 50%.

[0007] The raw material ratio is sodium sulfide:ethyl chloroacetate=0.4:1 to 0.7:1.

[0008] The solvent is cyclohexane, which is recovered and recycled through high-temperature distillation.

[0009] The reaction was carried out at 80 degrees Celsius for 3 hours.

[0010] The high temperature distillation is carried out under a vacuum degree of 140 to 180 degrees Celsius to improve the purity of the product.

[0011] The purity of the product is not less than 89%, and the yield is not less than 31%.

[0012] It also includes a step for determining the purity of sodium sulfide to ensure the stability of the reaction and the quality of the product. Through the method of this application, not only the production cost of EDTC is reduced, the impact on the environment is reduced, but also the production efficiency is improved. This innovative preparation process provides a new idea for the sustainable production of organic sulfur compounds, and is expected to have a far-reaching impact in many fields such as chemical industry, medicine and agriculture. With the increasing awareness of environmental protection and resource recycling, the promotion and application of this technology will have important social and economic value.

[0013] Specifically, sodium sulfide (the sodium sulfide content is about 50%), which is a byproduct of barium chemical industry, is intermittently added to react with ethyl chloroacetate, and the solvent and byproducts are separated and circulated into the reaction system, thereby realizing the recycling of raw materials, reducing costs, improving resource utilization efficiency, reducing environmental pollution, and optimizing reaction conditions. The synthesis process reported in the literature does not analyze and recycle the byproducts of the reaction, and can only achieve a yield of 80% and a purity of 90%. The present invention improves the yield and purity of ethylene thiodiglycolate through the recycling of byproducts; simplifies the purification process. The existing purification process needs to be separated by chromatography columns and requires a large amount of solvents. The present invention reduces production costs and improves economic benefits through a simple distillation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a high performance liquid chromatogram of the product of Example 2 of the present application, showing a purity of 96%;

[0015] Figure 2 This is a high performance liquid chromatogram of the product of Example 3 of the present application, which shows that the purity is 98%. DETAILED DESCRIPTION

[0016] Embodiment 1: add 7.8g sodium sulfide (0.06mol) and 30ml cyclohexane in a three-necked flask, add 12.25g ethyl chloroacetate (0.1mol) dropwise, and react for 3 hours at 80 degrees Celsius. After the reaction is completed, a crude product is obtained by suction filtration, washing and drying. The crude product is purified by high-temperature distillation to obtain high-purity ethylene thiodiglycolate, with a purity of 95% and a yield of 40.7%. The solvent and by-products that are steamed are then put into the next cycle reaction, and 100% recycling can be achieved.

[0017] Embodiment 2: 15.6g sodium sulfide (0.12mol) and 30ml cyclohexane were added to a three-necked flask, 12.25g ethyl chloroacetate (0.1mol) was added dropwise, and the mixture was reacted at 80 degrees Celsius for 3 hours. Through similar separation and purification steps, ethylene thiodiglycolate with a purity of 96% was obtained, and the yield was 35%. The solvent and by-products distilled out were then put into the next cycle reaction, and 100% recycling could be achieved.

[0018] Example 3: Sodium sulfide 12.48g (0.08mol ground), ethyl chloroacetate 12.25g (0.1mol), solvent cyclohexane 35mol. After the addition, the temperature was raised to 80 degrees Celsius, reacted for 3 hours, filtered and the filtrate was retained, the filter cake was washed with cyclohexane, and the filtrate was filtered at 60 degrees Celsius. The product was 5.81g, the yield was 35%, and the purity was 98%. The evaporated solvent and by-products were then put into the next cycle reaction, and 100% recycling could be achieved.

[0019] The above embodiments are only preferred embodiments of the present invention, and their purpose is to illustrate the technical solution of the present invention, and not to limit the protection scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing ethylene thiodiglycolate, characterized in that: The following steps are involved: (1) mixing sodium sulfide and ethyl chloroacetate in a solvent and reacting them; (2) after the reaction, obtaining a crude product by suction filtration, washing and drying; (3) purifying the crude product by high-temperature distillation to obtain high-purity ethylene thiodiglycolate; and (4) recovering and recycling the solvent and unreacted intermediate products.

2. A method for preparing ethylene thiodiglycolate according to claim 1, characterized in that: The sodium sulfide is a byproduct of barium chemical industry, and the content of sodium sulfide is 50%.

3. A method for preparing ethylene thiodiglycolate according to claim 1, characterized in that: The raw material ratio is sodium sulfide:ethyl chloroacetate=0.4:1 to 0.7:

1.

4. A method for preparing ethylene thiodiglycolate according to claim 1, characterized in that: The solvent is cyclohexane, which is recovered and recycled through high-temperature distillation.

5. A method for preparing ethylene thiodiglycolate according to claim 1, characterized in that: The reaction was carried out at 80 degrees Celsius for 3 hours.

6. A method for preparing ethylene thiodiglycolate according to claim 1, characterized in that: The high temperature distillation is carried out under a vacuum degree of 140 to 180 degrees Celsius to improve the purity of the product.

7. A method for preparing ethylene thiodiglycolate according to claim 1, characterized in that: The purity of the product is not less than 89%, and the yield is not less than 31%.

8. A method for preparing ethylene thiodiglycolate according to claim 1, characterized in that: The method also includes a step of determining the purity of sodium sulfide to ensure the stability of the reaction and the quality of the product.

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