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Method for preparing difluoroethanol through catalytic hydrogenation

A technology of difluoroethanol and catalytic hydrogenation, applied in the field of catalytic chemistry, can solve the problems of high equipment cost, complicated operation, large investment and the like

Inactive Publication Date: 2017-01-11
ZHEJIANG UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

On the other hand, the preparation of difluoroethanol adopts the traditional ester hydrogenation fixed-bed process, which has complicated operation, high equipment cost, large investment, and cannot effectively recover the catalyst, so it is not suitable for small-scale production in the field of fine chemicals

Method used

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  • Method for preparing difluoroethanol through catalytic hydrogenation
  • Method for preparing difluoroethanol through catalytic hydrogenation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Take a dry and clean reactor, and add magnets into it. Weigh 0.5g of Pd / C on weighing paper with an electronic balance, weigh 10g of ethyl difluorochloroacetate, 30g of ethanol, and 2.8g of triethylamine with a beaker, add them to the reaction kettle in sequence, and tighten the lid of the reaction kettle. Inflate 4MPa hydrogen with an instrument to check whether the kettle is leaking. If there is no leak, release the gas. Repeat three times, and inflate to 1.0MPa for the last time. Put it in a silicone oil bath at 150°C to react for 24 hours. After the time is up, take it out and cool it until the temperature drops below 60°C, release the gas, unscrew the lid of the reaction kettle, take a sample with a dropper, and conduct chromatographic analysis. The results are shown in Table 1. .

Embodiment 2

[0032] Take a dry and clean reactor, and add magnets into it. Weigh 0.5g of Pd / C on weighing paper with an electronic balance, weigh 5g of ethyl difluorochloroacetate, 15g of ethanol, and 1.4g of triethylamine with a beaker, add them to the reaction kettle in sequence, and tighten the lid of the reaction kettle. Inflate 4MPa hydrogen with an instrument to check whether the kettle is leaking. If there is no leakage, deflate it. Repeat three times, and inflate to 0.5MPa for the last time. Put it in a silicone oil bath at 180°C to react for 5 hours. After the time is up, take it out and cool it until the temperature drops below 60°C, release the gas, unscrew the lid of the reaction kettle, take a sample with a dropper, and conduct chromatographic analysis. The results are shown in Table 1. .

Embodiment 3

[0034] Take a dry and clean reactor, and add magnets into it. Weigh 0.5g of Pd / C on weighing paper with an electronic balance, weigh 10g of ethyl difluorochloroacetate, 30g of ethanol, and 2.8g of triethylamine with a beaker, add them to the reaction kettle in sequence, and tighten the lid of the reaction kettle. Inflate 4MPa hydrogen with an instrument to check whether the kettle is leaking. If there is no leakage, deflate it. Repeat three times, and inflate to 1MPa for the last time. Put it in a silicone oil bath at 180°C to react for 24 hours. After the time is up, take it out and cool it until the temperature drops below 60°C, release the gas, unscrew the lid of the reaction kettle, take a sample with a dropper, and perform chromatographic analysis. The results are shown in Table 1. .

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Abstract

The invention provides a method for preparing difluoroethanol through catalytic hydrogenation. The method has the beneficial effects that hydrogenation reduction reaction is carried out by using ethyl chlorodifluoroacetate as the raw material, a Pd / C as a catalyst, triethylanmine as an acid-binding agent and ethanol as a solvent; the atom F has higher electronegativity and HF can not be generated in the ethyl chlorodifluoroacetate hydrogenation process, but the C-Cl bond is easy to hydrogenate and HCl is easy to generate, thus neutralizing generated HCl by adding the acid-binding agent triethylanmine, propelling reaction to be carried out positively and increasing the conversion rate of ethyl chlorodifluoroacetate; on the other side, used in ester hydrogenation reaction, the Pd / C catalyst has good characteristics of low hydrogen-ester ratio, high raw material conversion rate, high alcohol selectivity, stable catalyst, and the like; and therefore, the method has the effect of solving the problems that the reaction process in the traditional ester hydrogenation process is complex, is high in investment and is not suitable for small-scale production in the fine chemical industry field.

Description

technical field [0001] The invention relates to the technical field of catalytic chemistry, in particular to a method for preparing difluoroethanol by catalytic hydrogenation. Background technique [0002] Fluoroalcohols and fluoroesters are aliphatic fluorine-containing intermediates, which have very good development prospects in the fields of pesticides, pharmaceutical synthesis, materials, dyes, etc., and are important organic synthesis intermediates with high added value. At present, a variety of methods for the synthesis of difluoroethanol have been proposed, especially by reducing difluoroacetyl chloride with hydride [AL. Its reduction [Patent JP61268639 of Asahi Chemical, 24 / 05 / 85], or by reduction of ethyl difluoroacetate with sodium borohydride [M.Lewis and E.deClerck-J ChemRes., Miniprint 8(2001), 844-56 ] to prepare difluoroethanol. [0003] In the industry, carboxylic acid esters are generally used to prepare fluoroalcohols and fluoroesters by catalytic hydroge...

Claims

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Application Information

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IPC IPC(8): C07C31/38C07C29/149C07C29/58
CPCC07C29/149C07C29/58C07C31/38
Inventor 闫宗刚邬海亮邢闯葛繁龙杨黎辉汪婧妍曹磊冷彪杨瑞芹许茂乾
Owner ZHEJIANG UNIVERSITY OF SCIENCE AND TECHNOLOGY
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