Preparation method of?bromofluoromethane

Abstract

The invention discloses a preparation method of bromofluoromethane. The method comprises the following steps: (1) subjecting 1,1,2,2-tetrafluoroethyl methyl ether to a catalytic cracking reaction in the presence of a catalyst, at the reaction temperature of 200-350 DEG C and the liquid space velocity at 0.3-0.8 / h, in order to obtain a reaction product containing CH3F, separating impurities in the reaction product and drying to obtain CH3F gas; and (2) mixing the CH3F gas obtained in the step (1) with Br2, preheating to 150-200 DEG C, and carrying out a thermal bromination reaction with reaction temperature of 400-800 DEG C, wherein a molar ratio of CH3F gas to Br2 is 1:0.8-5.5, separating impurities in the reaction products, removing water, cooling and distilling to obtain the bromofluoromethane product. The invention has the advantages of simple process, high yield, good selectivity and easy availability of raw materials.

Description

technical field [0001] The present invention relates to the preparation method of hydrobromocarbon, particularly a kind of preparation method of chlorofluoromethane. Background technique [0002] Bromofluoromethane (CH 2 BrF) is an important fluoromethylation reagent, which is more active than chlorofluoromethane when introducing a fluoromethyl group. It plays an important role in the synthesis of organic intermediates, fluorine-containing medicines, fluorine-containing pesticides and other chemicals. As we all know, it has Cephalosporins with broad-spectrum antibacterial activity have recently been found to have broader antibacterial activity after the introduction of fluoromethyl groups, especially for Pseudomonas aeruginosa; Ester, is an important cure for asthma drugs. [0003] Currently reported bromofluoromethane synthesis techniques have high raw material costs and complex processes. [0004] For example, in US5189229, the reduction of dibromofluoromethane with tri...

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Problems solved by technology

[0003] Currently reported bromofluoromethane synthesis technology has high cost of raw materials and complex process

[0004] As US5189229 uses tributyltin hydride to reduce dibromofluoromethane, although the yield is higher as 81.8%, the raw material tributyltin hydride is expensive, the production cost is high, and the process operation is complicated

[0005] EP0317125 uses sodium amalgam to reduce dibromofluoromethane, but the disadvantages are high raw material cost, complicated process and poor product selectivity

[0006] EP0503792 and EP0503793 respectively use high-valent metal fluorides and transition metal oxyfluorides to react with methylene bromide to synthesize bromofluoroalkanes. The disadvantage is that not only the yield of bromofluoromethane is low, but also the source of high-valent metal fluorides and transition metal oxyfluorides is difficult. complex process issues

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