Method for synthesizing difluoroethanol

Abstract

The invention discloses a method for synthesizing difluoroethanol. The method comprises the following steps of: (1), in a reaction kettle, adding polar or weak polar solvent and initiator in a mass ratio of (300: 1) to (30: 1); heating to 50-150 DEG C and continuously feeding vinylidene fluoride gas and hydrobromic acid gas in a mol ratio of (1: 1.05) to (1: 2.05); distilling to obtain 1,1-difluoro-2-bromoethane and absorbing tail gas by alkali solution; and (2), in the reaction kettle, adding 1,1-difluoro-2-bromoethane and sodium carbonate water solution with the mass concentration of 10-30% in a mol ratio of (2.5: 1) to (1.2: 1) and agitating under a backflow condition and reacting for 2-5 hours; cooling, adding methylbenzene, and distilling most water by co-boiling methylbenzene and water; then rectifying to obtain the difluoroethanol with the purity of more than 98%. The method provided by the invention has the advantages of high synthesis yield, less pollution, simple process, convenience in continuous operation of self-made vinylidene fluoride and hydrobromic acid gases, safety and reliability.

Description

technical field [0001] The invention relates to a compound synthesis method, in particular to a synthesis method of difluoroethanol. Background technique [0002] Difluoroethanol contains a special structure of difluoromethyl, so its properties are different from other alcohols, and it can participate in a variety of organic synthesis reactions, especially for the synthesis of fluorine-containing medicines, pesticides and dyes, and is an excellent choice for fluorine-containing fine chemicals One of the important intermediates. 2,2-Difluoroethanol is a colorless liquid at room temperature, with a boiling point of 96°C, a melting point of -28.2°C, a relative density of 1.71, and a refractive index of 1.338. Its acidity is equivalent to that of phenol. It is soluble in water, acid, ethanol, ether and other solvents. It is poisonous. Stable in nature. [0003] Existing the synthetic method of difluoroethanol now, as follows: [0004] W.G.Reifenrath et al [W.G.Reifenrath. J.M...

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Problems solved by technology

[0018] The disadvantage of this type of reaction is that the market price of the catalyst is more expensive, the hydrogen peroxide reagent is more dangerous, and the reactant is gas, there are certain difficulties in operation, and the yield is not ideal

[0019] In summary, these reactions or some auxiliary catalysts and solvents have higher market prices, resulting in increased synthesis costs; or some reaction synthesis methods are more complicated; or there is a shortcoming that the post-treatment process of difluoroethanol is relatively difficult, Overall cause its productive rate to drop obviously, can not make the product of high quality

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