Method for synthesizing difluoroethanol

A technology of difluoroethanol and its synthesis method, which is applied in the fields of chemical instruments and methods, preparation of hydroxyl compounds, and preparation of organic compounds, etc., which can solve problems such as difficult difluoroethanol treatment process, difficult operation, and increased synthesis cost, and achieve convenient continuous Production operation, high synthesis yield and easy operation

Active Publication Date: 2012-01-04
许茂乾
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  • Abstract
  • Description
  • Claims
  • Application Information

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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 solv

Method used

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  • Method for synthesizing difluoroethanol
  • Method for synthesizing difluoroethanol
  • Method for synthesizing difluoroethanol

Examples

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preparation example Construction

[0029] The steps of the synthetic method of difluoroethanol are as follows:

[0030] 1) In the reaction kettle, add a polar or weakly polar solvent and an initiator with a mass ratio of 300:1 to 30:1, heat to 50°C to 150°C, and continuously feed in a molar ratio of 1:1.05 to 1: 2.05% vinylidene fluoride gas and hydrobromic acid gas are reacted and distilled to obtain 1,1-difluoro-2-bromoethane, and the tail gas is absorbed with lye;

[0031] 2) In the reaction kettle, add 1,1-difluoro-2-bromoethane with a molar ratio of 2.5:1 to 1.2:1 and an aqueous sodium carbonate solution with a mass concentration of 10% to 30%, and stir the reaction under reflux conditions 2 hr to 5 hr, cool, add toluene, remove most of the water through azeotropic distillation of toluene and water, and then rectify to obtain difluoroethanol with a purity greater than 98%.

[0032] The polar or weakly polar solvent is N,N-dimethylformamide or acetonitrile. The used solvent is stable in property and good ...

Embodiment 1

[0045] 1) In a reaction kettle equipped with a gas inlet tube, a reflux condenser and a thermometer, add solvent acetonitrile and initiator azobisisobutyronitrile with a mass ratio of 40:1, and heat to 70°C; continuously feed in a molar ratio of 1: 1.2 Vinylidene fluoride gas and hydrogen bromide gas, react and distill to obtain 1,1-difluoro-2-bromoethane, and the tail gas is absorbed with lye.

[0046] 2) In a reactor equipped with a stirrer, a reflux condenser and a thermometer, add 1,1-difluoro-2-bromoethane with a molar ratio of 2.5:1 and an aqueous solution of sodium carbonate with a mass concentration of 30%. The reaction was stirred under reflux for 2 hr. Cool, add toluene, remove most of the water through azeotropic distillation of toluene and water, and then rectify to obtain difluoroethanol with a purity of 98% and a yield of 95%.

Embodiment 2

[0048] 1) In a reaction kettle equipped with a gas inlet tube, a reflux condenser and a thermometer, add the solvent N,N-dimethylformamide and the initiator azobisisobutyronitrile with a mass ratio of 100:1, and heat to 100 ℃; Continuously feed vinylidene fluoride gas and hydrogen bromide gas with a molar ratio of 1:1.1 for reaction and distillation to obtain 1,1-difluoro-2-bromoethane, and the tail gas is absorbed with lye.

[0049] 2) In a reactor equipped with a stirrer, a reflux condenser and a thermometer, add 1,1-difluoro-2-bromoethane with a molar ratio of 2:1 and an aqueous solution of sodium carbonate with a mass concentration of 20%. The reaction was stirred under reflux for 5 hr. Cool, add toluene, remove most of the water through azeotropic distillation of toluene and water, and then rectify to obtain difluoroethanol with a purity of 98.5% and a yield of 92%.

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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...

Claims

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Application Information

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IPC IPC(8): C07C31/38C07C29/124
Inventor 程桂林孟博许茂乾
Owner 许茂乾
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