Process for preparing high-purity methylsulfonic acid

Abstract

The invention discloses a process for preparing high-purity methylsulfonic acid. The process comprises the following steps: generating methylsulfonic sodium in a mixed reactor by the reaction of a sodium sulfite solution and monochloro methane at the temperature of 70-110 DEG C, then adding concentrated hydrochloric acid after dewatering, and generating a methylsulfonic acid solution and a corresponding sodium chloride salt precipitate; distilling off a hydrochloric acid solution from filtrate obtained after filtering sodium chloride salt, then distilling off acid water by depressurization, decompressing and distilling to obtain the methylsulfonic acid with high yield and high purity. The filtered salt sodium chloride can be used as a raw material for industrial electroanalysis, all the water which is distilled out is recovered as an assistant material, and the recovered hydrochloric acid solution is recovered for circular mechanical application. The invention has no pungent odor, no generation of waste water and waste residues, single reaction, easy acquirement of raw materials, simple operation and low cost, is suitable for industrialized scale production and is an environment-friendly industrialized process for preparing the high-purity methylsulfonic acid.

Description

field of invention [0001] The invention belongs to the technical field of organic chemistry industry, and in particular relates to a process for preparing high-purity methanesulfonic acid. Background technique [0002] In recent years, methanesulfonic acid has shown its unique use in the preparation of circuit boards of electronic products, and its application in the electroplating industry has become more and more extensive. The reports on the application of methanesulfonic acid and its salt system in electroplating are increasing year by year, and the market is increasing year by year. Methanesulfonic acid and its salts have unique uses as the main salt in brush plating copper, zinc, tin and cadmium plating. For example, copper methanesulfonate has two types in brush plating copper plating solution , that is, acid high-speed copper and high-accumulation alkali copper, which have excellent performance and a wide range of uses, which cannot be compared with other copper sal...

AI Technical Summary

Problems solved by technology

(1) Methanesulfonic acid (US2697722, US3509206, US3948922, WO0210123, US4859373) was prepared by methyl mercaptan-chlorine oxidative hydrolysis (US3392095, US4239696) and dimethyl disulfide-chlorine oxidative hydrolysis (US2697722, US3509206, US3948922, WO0210123, US4859373). However, there are serious air and water pollution, high raw material prices, and easily corroded equipment, which is not conducive to the development of enterprises

(2) adopt hydrogen peroxide to oxidize dimethyl disulfide or methyl mercaptan to make methanesulfonic acid technology, see patent documents US3392095, US4239696, CN1031838A (1989), CN93110559.5 (1993) and CN1165136A (1996), the The process realizes no pollution and no waste water discharge, but the price of raw materials is relatively high, hydrogen peroxide is a volatile substance, and storage and transportation are inconvenient

However, nitric acid is not easy to control during the oxidation reaction process, and produces toxic gas of nitric oxide, which has serious air and water pollution, and disadvantages such as inconvenient storage and transportation of raw materials.

It is not conducive to the large-scale safe production of small and medium-sized enterprises, and it is not in line with my country's chemical green and sustainable development strategy

(4) direct production (US1313853) with methyl thiocyanate direct oxidation method, its technique is simple, product is specific, has multiple oxidants, but all generates nitric oxide poisonous gas, is unfavorable for environmental protection

However, dimethyl sulfate is highly toxic, which is not good for transportation and storage

(6) BASF company improved into sulfur trioxide and methane or acetic acid reaction (US6207025, 2001), the raw material price of this method is lower, and synthesis yield is all very high, but process catalytic equipment and catalyst cost are higher, and equipment requirement is strict, And there is the problem of tail gas absorption, which is not conducive to the development of intermittent production scale of small and medium-sized enterprises in my country

This method is suitable for industrial production, but the process is not perfect at present, and there are process problems

And the price of sodium thiosulfate is on the high side, and the productive rate is on the low side, only about 40-45%

and environmental pollution problems

[0004] In short, the current synthesis processes of methanesulfonic acid have different advantages and disadvantages, especially in terms of environmental protection, cost, process operability, and sustainability of equipment utilization.