Green synthesis method of ethyl bromodifluoroacetate

A technology of ethyl difluorobromoacetate and a synthesis method, applied in chemical instruments and methods, carboxylate preparation, carboxylic acid halide preparation and other directions, can solve the problems of small pollution, poor safety, and high pollution, and achieves increased Safety, Emission Reduction, High Product Yield Effects

Active Publication Date: 2017-11-28
山东飞源新材料有限公司
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Aiming at the current situation of poor safety and high pollution in the preparation process of ethyl difluorobromoacetate, the present invention provides a synthesis method of ethyl difluorobromoacetate with low pollution and high safety

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] (1) Add 80.0g of 1,1-difluoro-1,2-dichloroethane and 237g of 20% sodium hydroxide solution into the high-pressure reactor, use 1.5g of tetrabutylammonium bromide as the catalyst, and Stirring, elimination reaction occurs to obtain 1,1-difluoro-2-chloroethylene;

[0030] (2) Pass the 1,1-difluoro-2-chloroethylene produced in the previous step into 90.1g liquid bromine at a rate of 0.12 g / min, react for about 6 hours, and then pass it into the reaction at a rate of 0.06 g / min At the end, keep 5 °C during the reaction, and distill to obtain 1,1-difluoro-1,2-dibromo-2-chloroethane with a purity of 99.1% and a yield of 93.4% in the above two steps;

[0031] (3) Add 100g of 30% sodium hydroxide solution and 1.6g of tetrabutylammonium bromide into the reactor, and drop 96.9g of 1,1-difluoro-1,2-dibromo-2 at a rate of 1.0g / min - Chloroethane reaction to obtain 1,1-difluoro-2-bromo-2-chloroethylene;

[0032] (4) The 1,1-difluoro-2-bromo-2-chloroethylene produced in the previou...

Embodiment 2

[0037] (1) Add 80.0g of 1,1-difluoro-1,2-dichloroethane and 324g of 30% sodium acetate solution into the high-pressure reactor, and use 1.5g of benzyltriethylammonium chloride as a catalyst, Stir at room temperature, and the elimination reaction occurs to obtain 1,1-difluoro-2-chloroethylene;

[0038] (2) Pass the 1,1-difluoro-2-chloroethylene produced in the previous step into 91.0g liquid bromine at a rate of 0.1 g / min, react for about 7 hours, and then pass it into the reaction at a rate of 0.05 g / min At the end, keep at -5 °C during the reaction, and distill to obtain 1,1-difluoro-1,2-dibromo-2-chloroethane with a purity of 99.3% and a yield of 95.4% in the above two steps;

[0039] (3) Add 300 g of 20 % sodium acetate solution and 1.8 g of benzyltriethylammonium chloride to the reactor, and add 94.6 g of 1,1-difluoro-1,2-dibromide dropwise at a rate of 0.8 g / min -2-chloroethane reaction to get 1,1-difluoro-2-bromo-2-chloroethylene;

[0040] (4) The 1,1-difluoro-2-bromo-...

Embodiment 3

[0045] (1) Add 80.5g of 1,1-difluoro-1,2-dichloroethane and 190g of 25% sodium hydroxide solution to the high-pressure reactor, use 2.0g of 18-crown-6 as the catalyst, and Stirring, elimination reaction occurs to obtain 1,1-difluoro-2-chloroethylene;

[0046] (2) Pass the 1,1-difluoro-2-chloroethylene produced in the previous step into 90.0g liquid bromine at a rate of 0.2 g / min, react for about 4 hours, and then pass it into the reaction at a rate of 0.07 g / min At the end, keep 0 °C during the reaction, and distill to obtain 1,1-difluoro-1,2-dibromo-2-chloroethane with a purity of 99.7% and a yield of 94.2% in the above two steps;

[0047] (3) Add 200 g of 15 % sodium hydroxide solution and 2.0 g of 18-crown-6 into the reactor, and add 96.3 g of 1,1-difluoro-1,2-dibromo-2 dropwise at a rate of 1.2 g / min - Chloroethane reaction to obtain 1,1-difluoro-2-bromo-2-chloroethylene;

[0048] (4) The 1,1-difluoro-2-bromo-2-chloroethylene produced in the previous step was passed into...

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Abstract

The invention provides a green synthesis method of ethyl bromodifluoroacetate. According to the method, 1,1-difluoro-1,2-dichloroethane is used as a starting material; elimination reaction is performed to obtain 1,1-difluoro-2-chloroethylene; the 1,1-difluoro-2-chloroethylene and bromine are subjected to addition to obtain 1,1-difluoro-1,2-dibromo-2-chloroethane; then, the elimination reaction is performed to obtain a 1,1-difluoro-2-bromine-2-chloroethylene; then, the 1,1-difluoro-2-bromine-2-chloroethylene and the bromine are subjected to addition to obtain 1,1-difluoro-1,2,2-tribromo-2-chloroethane; then, sulfur trioxide is used for oxidizing the 1,1-difluoro-1,2,2-tribromo-2-chloroethane; 1,1-difluoro-1-bromoacetyl chloride is obtained; finally, the 1,1-difluoro-1-bromoacetyl chloride and ethyl alcohol are esterified to obtain 2,2-difluoro-2-ethyl bromoacetate. The synthesis method has the advantages that the problems of recovery and utilization of waste materials of 1,1-difluoro-1,2-dichloroethane (R132b) are solved; no organic solvents are used in the reaction process; the oxidation step uses SO3 for oxidation; high temperature and high pressure or concentrated sulfuric acid is not needed; the safety is enhanced; the discharging of waste acid is reduced; the green production requirement is met; the product yield is relatively high; the green synthesis method is suitable for industrial production.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a synthesis method of ethyl difluorobromoacetate. Background technique [0002] Ethyl difluorobromoacetate is an intermediate of the antineoplastic drug gemcitabine. The current commercial production method is to prepare ethyl difluorobromoacetate by reacting difluorobromoacetyl halide with ethanol. The key technology is the preparation of difluorobromoacetyl halide. At present, the reported synthetic methods have the following: [0003] Zhao Jingwei et al. (Chinese Journal of Chemistry, 27(6), 1163-1168; 2009) reported a 1,1,2-trifluoro-1,2-dibromo-2-chloroethane in fuming Under the catalysis of sulfuric acid and mercuric oxide, difluorobromoacetyl fluoride is prepared, and then reacted with ethanol to obtain ethyl difluorobromoacetate. This method uses oleum, produces a large amount of waste water and waste acid, and the use of mercuric oxide is harmful to the hum...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C67/14C07C69/63C07C51/305C07C53/48C07C17/04C07C19/14C07C17/25C07C21/18
CPCC07C17/04C07C17/25C07C51/305C07C67/14C07C69/63C07C53/48C07C19/14C07C21/18
Inventor 崔丽艳肖玉岭李江
Owner 山东飞源新材料有限公司
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