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A kind of photooxidative preparation method of haloacetyl chloride

A halogenated acetyl and photooxidation technology, applied in the field of photooxidative preparation of halogenated acetyl chloride, can solve the problems of reducing the utilization rate of raw materials, harsh reaction conditions, easy by-products and the like, and achieves the improvement of utilization rate of raw materials and reaction conditions. Mild, avoids the effect of acid chloride photolysis

Active Publication Date: 2021-03-09
ZHEJIANG QUHUA FLUOR CHEM
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  • Application Information

AI Technical Summary

Problems solved by technology

Chinese Patent Publication No. CN102822134A reports that 1-alkoxy-1,1,2,2-tetrafluoroethane is used as a raw material to obtain difluoroacetyl chloride by contacting and thermally decomposing it with calcium chloride at a reaction temperature of 100-400°C, but The reaction temperature is high and the raw materials are not easy to obtain
Chinese Patent Publication No. CN103351292A reports heating 1,1,2-trichloro-2,2-difluoroethane (HCFC-122), oxygen and chlorine into a reactor at 90-200°C for photochemical reaction to prepare a The disadvantage of the method of chlorodifluoroacetyl chloride is that 1,1,1,2-tetrachloro-2,2-difluoroethane is easily by-produced by passing chlorine gas, and it is easily decomposed by direct irradiation with a high-pressure mercury lamp. Fluoride ions corrode the glass, thereby affecting the continuous operation of the reaction
Chinese Patent Publication No. CN103524325A reports the method of converting 1,1-difluorotetrachloroethane into chlorodifluoroacetyl chloride under the action of oxidant sulfur trioxide and catalyst chlorosulfonic acid. The disadvantage is that a large amount of liquid waste is produced as a by-product. And by-product more sulfuryl chloride
[0005] (1) Gas-phase catalytic oxidation method: Pass HCFC-123 and oxygen into a reactor equipped with a catalyst for oxidation. The catalyst is activated carbon or its metal-supported catalyst. The reaction temperature is 250-325 ° C, normal pressure, and the product selectivity is poor ( <75%), the disadvantage is that there are many kinds of decomposition products and the catalyst life is short
[0006] (2) Liquid-phase oxidation method: Japanese patent JP198241717 reports that HCFC-123 and oxygen are passed through at a temperature of 250-300°C and a pressure of up to 30kg / cm 2 In the reaction kettle, the conversion rate of HCFC-123 is greater than 90%, and the total selectivity of trifluoroacetyl chloride + trifluoroacetic acid is as high as more than 90%, but the reaction conditions are harsh, and the requirements for equipment are very high, so it is difficult to realize industrialization
[0007] (3) Photooxidation method: Chinese Patent Publication No. CN101735034A has reported that oxygen and chlorine gas are passed into a stirred reactor equipped with HCFC-123 liquid under light conditions to carry out a liquid phase reaction to obtain trifluoroacetyl chloride, requiring a gas-liquid phase interface There are light-shielding components below to prevent the generated trifluoroacetyl chloride from being radiated by the mercury lamp in the gas phase space, but the radiation of the mercury lamp into the liquid phase will still cause the decomposition of trifluoroacetyl chloride and corrode the glass, and the introduction of chlorine gas will make the reaction unsafe , while bringing trifluorotrichloroethane and other by-products, reducing the utilization rate of raw materials

Method used

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  • A kind of photooxidative preparation method of haloacetyl chloride

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] A copper sulfate solution with a concentration of 35.0g / L is poured into the quartz cold trap continuously and circularly at a flow rate of 11L / min as a filter solution to filter out ultraviolet light with a wavelength of less than 300nm. Oxygen and HCFC-123 are injected into the mixer at a molar ratio of 1.5:1, mixed and vaporized, and then passed into the reactor for photooxidation reaction. The reaction temperature is 40°C, the residence time is 3s, and the power of the metal halide lamp is 700W. The reaction has been running continuously for one month, and the reactor and components have no obvious corrosion. Sampling and analysis at the outlet of the reactor showed that the conversion rate of HCFC-123 was 97.1%, and the selectivity of trifluoroacetyl chloride was 99.6%.

Embodiment 2

[0037] A copper sulfate solution with a concentration of 20.0g / L is continuously injected into the quartz cold trap with a flow rate of 10L / min as a filter solution to filter out ultraviolet light with a wavelength of less than 300nm. Ozone and HCFC-123 are injected into the mixer at a molar ratio of 1.5:1, mixed and vaporized, and then passed into the reactor for photooxidation reaction. The reaction temperature is 30°C, the residence time is 3s, and the power of the high-pressure mercury lamp is 700W. The reaction has been running continuously for one month, and the reactor and components have no obvious corrosion. Sampling and analysis at the outlet of the reactor showed that the conversion rate of HCFC-123 was 98.3%, and the selectivity of trifluoroacetyl chloride was 99.9%.

Embodiment 3

[0039] A copper sulfate solution with a concentration of 50.0g / L is continuously injected into the quartz cold trap at a flow rate of 22L / min as a filter solution to filter out ultraviolet light with a wavelength of less than 300nm. Oxygen and HCFC-132a are injected into the mixer at a molar ratio of 2.5:1, mixed and vaporized, and then passed into the reactor for photooxidation reaction. The reaction temperature is 50°C, the residence time is 6s, and the power of the medium-pressure mercury lamp is 500W. The reaction has been running continuously for one month, and the reactor and components have no obvious corrosion. Sampling and analysis at the outlet of the reactor showed that the conversion rate of HCFC-132a was 96.6%, and the selectivity of difluoroacetyl chloride was 99.5%.

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Abstract

The invention discloses a photooxidative preparation method of haloacetyl chloride. The haloalkane is mixed and vaporized with an oxygen source, and then passed into a reactor for photooxidation reaction to obtain haloacetyl chloride. The temperature of the photooxidation reaction is 5-60°C. The residence time of the material is 1-50s, the molar ratio of the oxygen source to the halogenated alkanes is 0.1-5:1, the reactor is equipped with a quartz cold trap, the quartz cold trap is composed of a quartz inner shell and a quartz outer shell, and the quartz inner shell is equipped with A light source, a double-layer cold trap jacket is formed between the quartz inner shell and the quartz outer shell, and the double-layer cold trap jacket is filled with a circulating filter liquid, which absorbs the ultraviolet light less than 300nm produced by the light source filter out. The invention has the advantages of simple process, high yield, safety and environmental protection, and continuous operation.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a photooxidative preparation method of haloacetyl chloride. Background technique [0002] Difluoroacetyl chloride has a very wide range of applications as a medicine, pesticide intermediate, reaction reagent, especially as a reagent for introducing difluoromethyl or difluoroacetyl groups into organic compounds, and its preparation method has received more and more attention. Chinese Patent Publication No. CN102822134A reports that 1-alkoxy-1,1,2,2-tetrafluoroethane is used as a raw material to obtain difluoroacetyl chloride by contacting and thermally decomposing it with calcium chloride at a reaction temperature of 100-400°C, but The reaction temperature is high and the raw materials are not easy to obtain. U.S. Patent No. 5,905,169 reported that 1,1-dichloro-2,2-difluoroethane (HCFC-132a) and oxygen were used as raw materials to prepare difluoroacetyl chloride with a selectiv...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C51/58C07C53/48
CPCC07C51/58C07C53/48
Inventor 洪江永杨波张彦赵阳周华东吴承民
Owner ZHEJIANG QUHUA FLUOR CHEM