CN-121990954-A - Synthesis optimization process of isopropyl ethyl thiourethane

Abstract

The invention discloses a synthesis optimization process of isopropyl ethyl thiamine ester, which is characterized in that the dosage of liquid alkali is reduced by 13%, and the mode of adding residual chloroacetic acid (the residual chloroacetic acid is slowly and uniformly added for 60% 10min before ① and is stirred for 20min, then added for 15% and is added for 40min, then added for 15% and is continuously stirred for 80 min.) for 3 times in a reaction stage of preneutralization of 87% liquid alkali is adopted. The process can obviously inhibit side reactions, reduce the byproduct content at the position of chromatographic 5min from 0.25% to below 0.1%, realize the product content improvement of approximately 0.5% and the yield improvement of approximately 4.3%, greatly reduce the cost of liquid alkali raw materials, have better comprehensive benefits than the traditional process, are simple and convenient to operate, and are suitable for industrialized popularization.

Inventors

• LI WENQIANG

Assignees

• 李文强

Dates

Publication Date

20260508

Application Date

20260131

Claims (3)

1. 1. The synthesis optimization process of isopropyl ethyl thiamine ester is characterized by comprising the following steps of: Step 1, preneutralization, namely adding 87% of the total amount of liquid alkali which is reduced by 13% into a reaction container, mixing with chloroacetic acid neutralization dosage, stirring and neutralizing at room temperature, wherein the rotating speed is 500r/min, and the neutralization time is 10min; step 2, adding xanthate, namely adding sodium xanthate, and stirring at room temperature at the rotating speed; The intermediate in the step 3 is formed by adding 60% of residual chloroacetic acid slowly and uniformly for 10min before ① for 3 times, stirring for 20min, adding 15% of the residual chloroacetic acid, stirring for 40min, adding 15% of the residual chloroacetic acid, and continuing stirring for 80min; step 4, amination reaction, namely adding monoethylamine, stirring and aminating for 4 hours to obtain a crude product of the ethionamide ester; and 5, separating the crude product, wherein the non-aqueous phase is isopropyl ethyl thiourethane.
2. 2. The process according to claim 1, wherein the total amount of liquid alkali is reduced by 13% compared with the conventional process, and the process can significantly inhibit side reactions, and the byproduct content at 5min of chromatography is reduced from 0.25% to less than 0.1%.
3. 3. The process according to claim 1, wherein the content of the obtained ethionamide ester product is improved by about 0.5% compared with the traditional process, the yield is improved by about 4% compared with the traditional process, the cost of liquid alkali raw materials is reduced, and the comprehensive benefit is better than that of the traditional process.

Description

Synthesis optimization process of isopropyl ethyl thiourethane Technical Field The invention relates to the technical field of organic synthesis, in particular to a synthesis optimization process of isopropyl ethyl thiamine ester, which realizes multiple effects of reducing cost, improving quality and reducing side effects by improving a feeding mode and the dosage of liquid alkali. Background Isopropyl ethyl thiamine is an important mineral separation collector, and the traditional synthesis process generally adopts a mode of one-time neutralization of 100% liquid alkali and one-time full feeding of chloroacetic acid, and has the following defects: 1. The consumption of liquid alkali is large, and the cost of raw materials is high; 2. the chloroacetic acid is fed once, so that local pH fluctuation is easy to cause generation of sulfur-containing byproducts, and the purity of the product and the utilization rate of raw materials are low; 3. the yield and content fluctuation of the small-scale test and industrial production are large, and the process stability is insufficient. In the prior art, aiming at the optimization of thiamine ester, the optimization is focused on a single index (such as content or yield), and the cooperative optimization of liquid alkali reduction, byproduct inhibition and quality improvement is not realized. Therefore, developing a synthetic process with better comprehensive benefit has important industrial application value. Disclosure of Invention The invention aims to overcome the defects of the traditional process, and provides a synthesis optimization process of isopropyl ethyl thiamine ester, which realizes triple technical effects by accurately regulating and controlling the feeding mode and the liquid alkali consumption: 1. The liquid alkali decrement is 13 percent, compared with the traditional process, the liquid alkali consumption is reduced, the raw material cost is greatly reduced, and the optimal liquid alkali decrement of the process is 10 percent; 2. Chromatographic detection shows that the peak content of the characteristic byproducts at 5min is reduced from 0.25% to less than 0.1% in the traditional process, and the reduction is more than 60%; 3. The product quality is improved, the product content is positively improved by about 0.5 percent compared with the traditional process, and the raw material utilization rate and the process stability are obviously improved; 4. the yield is obviously improved by about 4.3 percent compared with the yield of the parallel traditional control group in the same period, and the process economy is further improved. The core technical scheme of the invention is as follows: the synthesis optimization process of isopropyl ethyl thiamine ester comprises the following steps: 1. pre-neutralization, namely adding 87% of the total amount of liquid alkali which is reduced by 13% into a reaction container, mixing with the neutralization adding amount of chloroacetic acid, and stirring and neutralizing at room temperature; 2. adding excessive sodium xanthate (10% -20% of excessive sodium xanthate), and stirring at room temperature at rotating speed; 3. Regulating the pH of the intermediate, namely adding the rest chloroacetic acid for 3 times, adding about 60% for the first time, adding about 20% after 20min, adding about 20% for 30min, and regulating the pH to a target value in times; 4. amination reaction, namely adding monoethylamine, stirring and amination to obtain a target product; 5. and (3) post-treatment, namely directly weighing (wet weight) the product after separating liquid, and detecting the content accounting yield by combining with chromatography. Detailed Description Experimental raw materials and instrument Raw materials including chloroacetic acid (purity is not less than 70%), liquid alkali (NaOH concentration is 30%), sodium xanthate (purity is not less than 84%), monoethylamine (purity is not less than 70%), and tap water; The apparatus comprises a beaker (1L), an electronic balance (precision 0.01 g), a pH meter, a stirrer and a gas chromatograph (GC-6890). Control group (traditional technology) 1. Pre-neutralization, namely adding the traditional full amount of liquid alkali (92.42 g) and the neutralization adding amount (97.51 g) of chloroacetic acid, stirring at room temperature (500 r/min) for neutralization, and cooling to room temperature; 2. adding 136.55g sodium xanthate, and stirring for 2.5h; 3. amination reaction, namely adding 49.18 monoethylamine, stirring and amination for 30min; 4. the post-treatment, weighing 76.34g of wet weight after liquid separation, detecting the content by chromatography to 98.18%, and obtaining 76.34% of yield (calculated by taking chloroacetic acid as a limiting reagent), wherein the content of byproducts at 5min of chromatography is 0.24%. Optimizing group (inventive process) 1. Pre-neutralization, namely adding 87 percent (80.32 g) of liquid alkali which is reduced by 13 percen