A kind of method that water method prepares methylsulfonamide

Abstract

The invention discloses a method for preparing methylsulfonamide by an aqueous method, which uses triethylamine as a catalyst, reacts methylsulfonyl chloride with ammonia water, and generates a mixed solution of ammonium chloride and methylsulfonamide; the mixed solution is passed through After separation of triethylamine, deamination and desalination, the methylsulfonamide can be obtained. The method is prepared by the water method, and no organic solvent is involved in the whole preparation process; the shortcomings of organic solvents such as high toxicity, high price, high risk, and high cost are overcome; the invention adds catalyst triethylamine to overcome the low selectivity of ammonia water reaction The disadvantages of the method greatly improve the yield of the process; in summary, the application has the characteristics of process safety, process environmental protection, high selectivity of raw materials, and high yield.

Description

technical field [0001] The invention belongs to the technical field of fine chemicals, in particular to a method for preparing methylsulfonamide by water method. Background technique [0002] Methylsulfonamide is an important fine chemical product intermediate, which can be widely used as a raw material for the synthesis of medicines and pesticides. . [0003] Regarding the preparation of methylsulfonamide, it is prepared by reacting methylsulfonyl chloride with ammonia as the main raw material, and there are mainly two processes of water method and organic solvent method. Organic solvent method has a lot, for example, use tetrahydrofuran, dioxolane and other cyclic ethers as reaction solvent and extraction solvent in U.S. patent application US4970339 and US5166431; Then use ethylene glycol dimethyl ether as reaction and extraction solvent in U.S. patent application US5159112 Solvent; U.S. Patent Application No. 5,455,377 uses aliphatic nitriles such as acetonitrile as a r...

AI Technical Summary

Problems solved by technology

But the use of organic solvent has following definite shortcoming: with respect to main raw material methanesulfonyl chloride and product methanesulfonamide, used solvent is expensive, so the recycling of solvent is necessary, and the rate of recovery of solvent determines The cost is high; the organic solvent has a low flash point, high volatility, and requires hot filtration, which greatly increases the danger of the production process, and it is difficult to achieve both separation effect and safety in industrial production; the separated by-product chlorine The ammonium chloride salt contains organic solvents, which also brings about the problem of solvent recovery in the salt and environmental protection problems

But this method has several serious problems: the one, ammoniacal liquor is used as reaction raw material, there is the side reaction of significant raw material methanesulfonyl chloride hydrolysis, and reaction selectivity is far lower than solvent method; (Because the presence of ammonium salts will cause the chlorine in the product to be high) If the replacement is clean, an excessive amount of sodium hydroxide must be added (that is, the system is strongly alkaline), which will easily cause deamination at high temperature (60-100°C) ) the alkaline hydrolysis of product methylsulfonamide in the process, thereby further reducing productive rate; The 3rd, the ammonium chloride that changes by-product is easy to sell is the sodium chloride that is difficult to commercially handle, has brought environmental protection problem

Patent CN102050765B only describes the process, but does not mention the quality and yield of the product