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Industrialized synthetic method of ethyl difuoroacetate

A technology of difluoroacetate and synthesis method, which is applied in chemical instruments and methods, preparation of carboxylic acid esters, preparation of organic compounds, etc., can solve the problem of inability to synthesize products, diethylamine is not suitable for large-scale production, and does not have issues of authenticity

Inactive Publication Date: 2013-01-16
上海品沃化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the preparation process of difluoroacetyldiethylamine provided by this patent is to use dichloroacetyldiethylamine and anhydrous KF in sulfolane as a solvent and tetrabutylammonium bromide as a phase transfer catalyst to undergo a fluorine substitution reaction. The solvent sulfolane used for fluorine substitution will decompose in a small amount above 140°C to produce SO 3 The gas will have an adverse effect on the reaction, and there is no fluorination reaction rate as high as 84% ​​as reported in the patent. The laboratory has concluded through research that this process is a process that cannot synthesize products. It is not difficult to find out through comprehensive analysis This process should be the product of the combination of academic research by the company and the college, and it does not have the authenticity of industrialization. Moreover, the key raw material diethylamine used in this process is not suitable for large-scale production, and it is difficult to recover in industry, which is not conducive to reducing product production costs.

Method used

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  • Industrialized synthetic method of ethyl difuoroacetate
  • Industrialized synthetic method of ethyl difuoroacetate
  • Industrialized synthetic method of ethyl difuoroacetate

Examples

Experimental program
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Effect test

example 1

[0027] 1.1 Add 2Kg of toluene and 500g of chloroacetyl chloride into a 5L four-necked flask, seal the system (with a buffer ball), cool down in an ice-salt bath to 0-5°C, and slowly and quantitatively inject 315g of dimethylamine gas into the dimethylamine cylinder. Naturally rise to room temperature and react for 3-5 hours, filter with suction, wash the filter cake with an appropriate amount of toluene, concentrate the filtrate to obtain the crude product, and rectify at 57-62°C to obtain the pure product N,N-dimethyl-dichloro Acetamide 499.7g, yield 94.5%, collect amine salt filter cake for recovery of dimethylamine for later use.

[0028] 1.2 Add 468g of pure N,N-dimethyl-dichloroacetamide, 1170g of diethylene glycol, and 442g of anhydrous KF to a 3L four-neck flask, connect to a drying tube, stir, and heat up to 150-160°C for 12-16 hours . After cooling down to room temperature, rectification under reduced pressure at 65-68°C (vacuum degree 70-80 mmHg) yielded 283.6 g of ...

example 2

[0031] 2.1 Add 2Kg of toluene and 500g of dichloroacetyl chloride into a 5L four-neck flask, seal the system (with a buffer ball), cool down in an ice-salt bath to 0-5°C, slowly and quantitatively inject 315g of dimethylamine gas into the dimethylamine cylinder, and end Then naturally rise to room temperature to react for 3-5 hours, filter with suction, wash the filter cake with an appropriate amount of toluene, concentrate the filtrate to obtain the crude product, (vacuum degree 0-5mmHg) rectify at 57-62°C to obtain the pure product N,N-dimethyl-di Chloroacetamide 506.6g, yield 95.8%, collect the amine salt filter cake for recovery of dimethylamine for later use.

[0032] 2.2 Add 468g of pure N,N-dimethyl-dichloroacetamide, 1170g of diethylene glycol, and 442g of anhydrous KF to a 3L four-neck flask, connect to a drying tube, stir, and heat up to 150-160°C for 12-16 hours . After cooling down to room temperature, rectification under reduced pressure at 65-68°C (vacuum degree...

example 3

[0035] 3.1 Put the dimethylamine hydrochloride collected by amination into the flask after the esterification reaction, add 500g of toluene, add 40% concentrated NaOH aqueous solution dropwise, control the material at 40-50°C, and the dimethylamine gas generated by the reaction passes through After drying the tube with alkali, it is directly passed into a 5L amination (500g dichloroacetyl chloride) reaction flask. After the dimethylamine gas is released, the amination reaction takes 1 hour, and the reaction is quenched with ethanol for sampling and filtration. 6-7% is detected by GC. The raw material dichloroacetyl chloride was not completely reacted, and 22g of dimethylamine gas was introduced into the dimethylamine steel cylinder, then raised to room temperature and reacted for 3 to 5 hours, then suction filtered, the filter cake was washed with an appropriate amount of toluene, and the filtrate was concentrated to obtain a crude product, (vacuum degree 0 to 5mmHg ) at 57-62°...

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Abstract

The invention discloses an industrialized synthetic method of ethyl difluoroacetate. Difluoroacetate is generated through catalysis of difluoroacetamide and low alcohols under strong acid, and the selectivity of the difluoroacetate reaches more than 95%. The method is characterized in that dichloro-acetamide is prepared from secondary amide that is easy to recover and can be in continuous operation at the same time, the problem that fluorine substitution reaction is difficult to carry out under the combination of a common solvent and a catalyst is solved through a solvent, and the solvent has the effect of a phase transfer agent, and is low in cost and convenient to recover.

Description

technical field [0001] The present invention relates to an industrial synthesis method of difluoroacetate represented by the following general formula (3) useful for synthesizing pesticide intermediates. [0002] [0003] (R in the general formula 1 Represents an alkyl group with 1 to 4 carbon atoms, which can be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl) Background technique [0004] Difluoroacetate is an intermediate for the synthesis of various special medicines and pesticides, and there are many synthetic methods at present. [0005] EP0694523 discloses a method in which tetrafluoroethylene and methanol undergo an addition reaction under catalytic conditions, and the product undergoes catalytic cracking to obtain difluoroacetyl fluoride, and then undergoes an esterification reaction with alcohol to obtain difluoroacetate. [0006] CA2154847 discloses a method similar to EP0694523, using alkoxytetrafluoroethane to undergo catalytic ...

Claims

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Application Information

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IPC IPC(8): C07C69/63C07C67/20C07C233/05C07C231/02C07C231/12
Inventor 张奇方
Owner 上海品沃化工有限公司
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