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A kind of method for preparing difluoroacetate by gas-solid phase reaction

A technology of difluoroacetate and difluorochloroacetate alkyl ester is applied in the field of preparing difluoroacetate by gas-solid phase reaction, and can solve the problems of equipment corrosion, difficulty in obtaining difluoroacetonitrile, long process flow and the like

Active Publication Date: 2021-05-11
ZHEJIANG RES INST OF CHEM IND CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] Among the above four preparation methods: the fluoride salt fluorination method has problems such as long process flow, low total yield, and serious equipment corrosion; in the esterification method of difluoroacetyl fluoride and alcohol, the process route using tetrafluoroethylene as raw material exists Long process flow, need to use explosive raw materials, easy to generate highly toxic by-products, etc.; the reduction dechlorination method has high production costs; although the difluoroacetonitrile method has a simple process and high yield, the raw material difluoroacetonitrile is not easy to obtain and the production cost higher disadvantage

Method used

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  • A kind of method for preparing difluoroacetate by gas-solid phase reaction
  • A kind of method for preparing difluoroacetate by gas-solid phase reaction
  • A kind of method for preparing difluoroacetate by gas-solid phase reaction

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] Embodiment 1, Pd / AC catalyst (sample A)

[0056] Grind the activated carbon and screen out 10-20 meshes as a carrier, weigh 100g of activated carbon, put it into 300ml of hydrochloric acid solution with a concentration of 10%, in a water bath with a temperature of 80°C, stir and reflux for 6 hours, take it out, and dissolve it with distilled water The acid-washed activated carbon was washed to neutrality, and then dried at 100°C for use.

[0057] Weigh 0.77g of PdCl 2 , dissolved in 2ml of concentrated hydrochloric acid, added 15g of distilled water to make PdCl 2 After fully dissolving, add 2g of citric acid, add 14.5g of the above acid-washed activated carbon to the above solution, impregnate for 24h, and freeze-dry and dehydrate at -20°C for 20h. Roasting in a nitrogen atmosphere for 4h, cooled for later use.

Embodiment 2

[0058] Embodiment 2, Pd-Ce / AC catalyst (sample B)

[0059] Weigh 0.93g of Ce(NO 3 ) 3 ·6H 2 O, dissolved in 15g of distilled water, after fully dissolving, add 15g of activated carbon treated in Example 1, impregnate for 24h, dry at 100°C, then roast at 400°C for 4h in a nitrogen atmosphere, cool and set aside.

[0060] Weigh 0.51g of PdCl 2 , dissolved in 2ml of concentrated hydrochloric acid, added 10g of distilled water to make PdCl 2 After fully dissolving, add 1.3g of citric acid, then add 10g of activated carbon containing additive Ce after the above-mentioned treatment, impregnate for 24h, and freeze-dry and dehydrate at -20°C for 20h. Calcined in nitrogen atmosphere for 4h, cooled for later use.

Embodiment 3

[0061] Embodiment 3, preparation of methyl difluoroacetate

[0062] The sample A is used as a catalyst for preparing methyl difluoroacetate by catalytic hydrodechlorination of methyl difluorochloroacetate. The reaction was carried out in a fixed bed reactor made of stainless steel tube (inner diameter: 20mm, length: 600mm), filled with 10ml, about 5g of sample A catalyst, and the reaction temperature was set at 150°C, 200°C, 250°C and 300°C, the operating pressure is normal pressure, the raw material methyl difluorochloroacetate is vaporized by the vaporizer (150°C) and mixed with hydrogen, and the space velocity of the raw material gas is about 30h -1 , the flow ratio of reducing gas hydrogen and methyl difluorochloroacetate is about 4.

[0063] The reaction product is analyzed and determined by gas chromatography analysis method, and then the product is collected by low-temperature condensation, and the unreacted hydrogen is vented. The results of the reaction analysis are...

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Abstract

The invention discloses a method for preparing difluoroacetate, which comprises the steps of obtaining methyl difluoroacetate through a gas-phase hydrodechlorination reaction of methyl difluorochloroacetate and hydrogen under the action of a catalyst, the catalyst comprising an active Components and additives, the active component is Pd, and the additives are selected from at least one of Ce, Cu, La and Ni. The method provided by the invention has the advantages of mild reaction conditions and high product selectivity.

Description

technical field [0001] The invention relates to a gas-solid phase catalytic hydrodechlorination reaction, in particular to a method for preparing difluoroacetate by gas-solid phase reaction. Background technique [0002] Difluoroacetate is mainly used as an intermediate for pesticides, pharmaceuticals, and fluorine-containing fine chemicals, and can also be used as a solvent for lithium battery electrolytes. For the preparation route of difluoroacetate, following reports are arranged in the prior art: [0003] (1) Fluoride salt fluorination method [0004] Japanese patent JP6228043 discloses a production method of using dichloroacetic acid derivatives as raw materials, fluorinating with fluoride salts, and then synthesizing difluoroacetic acid. At a reaction temperature of 10°C, dichloroacetyl chloride was first reacted with diethylamine in toluene solvent to obtain 89% N,N-diethyldichloroacetamide, and then at a reaction temperature of 150°C, N,N-di Ethyl dichloroacetami...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C67/317C07C69/63B01J23/44B01J23/63
CPCB01J23/44B01J23/63C07C67/317C07C69/63
Inventor 刘武灿石能富马超峰李玲金佳敏
Owner ZHEJIANG RES INST OF CHEM IND CO LTD
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