Method of manufacturing thioacetic acid

Abstract

The invention discloses a preparation method of the thioacetic acid. The method is that the sodium sulphide produced by the carbon and the mirabilite is adopted to react with the hydrochloric acid to prepare the hydrogen sulfide, and then under the good air-tightness, the hydrogen sulphide gas processed by the dryer reacts with the acetic anhydride to gain the nearly colorless thioacetic acid with content not less than 95 per cent, boiling range of 88 DEG C. to 91DEG C., heavy metals less than 0.0002 per cent, melting point less than minus 17 DEG C. and flash point less than 1 DEG C. through reduced pressure distillation and rectification. The preparation method has convenient operation, which avoids the pollution on the external environment during production, greatly increases the purification of the product content and the product quality and lowers the production cost.

Description

technical field [0001] The present invention relates to a kind of preparation method of thioacetic acid. Background technique [0002] Thioacetic acid is a basic industrial raw material used in flavors, fragrances, pharmaceutical and chemical industries, molecular formula: C 2 h 4 OS, structural formula: [0003] [0004] Molecular weight: 76, content ≥98% (or ≥95%); color GB5, almost colorless; heavy metal <0.0001% (or <0.0002%); boiling range 87-91°C; specific gravity 1.075; melting point <-17°C ; Flash point 1°C. At present, the methods used to synthesize thioacetic acid mainly include the reaction of glacial acetic acid and phosphorus pentasulfide to produce, because of its difficult separation, low yield, poor quality, high cost, and serious environmental pollution, or the synthesis reaction of acetic anhydride and hydrogen sulfide Production of thioacetic acid, but this method is technically difficult, difficult to operate, and in the process of synthes...

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Problems solved by technology

At present, the methods used by people to synthesize thioacetic acid mainly include the reaction of glacial acetic acid and phosphorus pentasulfide to produce, because of its difficult separation, low yield, poor quality, high cost, and serious environmental pollution, or the synthesis reaction of acetic anhydride and hydrogen sulfide Production of thioacetic acid, but this method is technically difficult, difficult to operate, and in the process of synthesis and preparation, it is easy to generate H 2 The leakage of S gas and waste glacial acetic acid by-products cause pollution to the external environment, and the thioacetic acid produced by synthesis is severely decomposed and separated in the subsequent purification process, and the yield and content are very low, and the content is lower than 93%. , not only reduces the quality of the product, but also causes a certain waste of materials

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