Production methods
1. It is obtained by the reaction of inorganic or organic sulfur compounds with sodium and potassium salts of monochloroacetic acid. For example, monochloroacetic acid reacts with sodium sulfide and sulfur to form dithiodiacetic acid, and then reduces with zinc and acid. Or thiocarbamate reacts with monochloroacetic acid and the product is prepared by hydrolysis; Monochloroacetic acid reacts with thiourea to produce isothiourea acetic acid, and then converts barium hydroxide to precipitate, and then makes sulfhydryl acetic acid aqueous solution by sulfuric acid. 60%-70% solution can be prepared by evaporation, the yield is above 70%.
2. In less than 25 ºC temperature, sodium carbonate solution is added to chloroacetic acid to ph 7 ~ 8, then add the thiourea reaction, generate acetic acid, urea, acetic acid from thiourea in thermal reaction with sodium hydroxide under 78 ~ 80 ºC for 2 h, the reaction after cooling to 40 ºC, adding concentrated hydrochloric acid to ph value of 3, reoccupy ether extraction, extraction of the ether layer after stir in fully activated carbon filtration, the filtrate after add zinc powder reduced pressure distillation, a quick tasted glucosinolates glycolic acid. The reaction equation of the process is:
3. Mix 16% chloroacetic acid solution with 15% potassium thiohydride solution,ClCH2COOH∶KHS= 1:2 (molar ratio). After heating, add barium chloride saturated solution of the same quality as chloroacetic acid, then add 25% concentrated ammonia water, stir evenly, then stand, filter, add concentrated hydrochloric acid of the same volume in the filtrate, then use ether extraction, distillation to remove ether, finally, distillation at 2000Pa, collect 104 ~ 106ºC fraction, obtain thioglycolic acid. The reaction equation is:
4. Sodium thiohydride and chloroacetic acid are prepared under the action of hydrogen sulfide and nitrogen.
5. Chloroacetic acid, sodium thiosulfate and sodium hydroxide were synthesized, and then the product was obtained by acid hydrolysis, extraction and distillation.