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Method for preparing fluorine-containing compound ch2f-r (r=h or -cf3) by pyrolysis of difluoromethane

A technology of CH2F-R and difluoromethane, which is applied in the field of preparing fluorine-containing compound CH2F-R, and achieves the effect of easy operation and control and good repeatability

Active Publication Date: 2019-03-22
BEIJING INSTITUTE OF TECHNOLOGYGY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] Up to now, there is no public literature report on the technology of preparing HFC-134a and monofluoromethane (HFC-41) by pyrolysis of difluoromethane as raw material

Method used

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  • Method for preparing fluorine-containing compound ch2f-r (r=h or -cf3) by pyrolysis of difluoromethane
  • Method for preparing fluorine-containing compound ch2f-r (r=h or -cf3) by pyrolysis of difluoromethane
  • Method for preparing fluorine-containing compound ch2f-r (r=h or -cf3) by pyrolysis of difluoromethane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] The tubular reactor made of Incon alloy with an inner diameter of 1 / 2 inch and a length of 30 cm is heated up to 800-1000° C., and difluoromethane (HFC-32) is introduced to react, and the residence time of difluoromethane in the reactor is controlled to be 15 seconds, the reaction pressure is normal pressure, after the reaction product is washed with water, alkali washed, dried to remove water, and reacted for 10 hours, a gas phase sample is taken for gas chromatography detection, and the results are shown in Table 6.

[0032] Table 1 The reaction result of pyrolysis of difluoromethane alone

[0033]

Embodiment 2

[0035] The tubular reactor made of Incon alloy with an inner diameter of 1 / 2 inch and a length of 30 cm is heated to 800-1000 ° C, and difluoromethane (HFC-32) is introduced to react with methane, and the molar ratio of difluoromethane to methane is controlled as 1:1, the residence time of difluoromethane and methane in the reactor is 15 seconds, and the reaction pressure is normal pressure. After the reaction product is washed with water, washed with alkali, dried to remove water, and reacted for 10 hours, a gas phase sample is taken for gas chromatography detection , the results are shown in Table 7.

[0036] Table 2 Reaction results of co-pyrolysis of difluoromethane and methane

[0037]

Embodiment 3

[0039] The tube reactor made of Incon alloy with an inner diameter of 1 / 2 inches and a length of 30 cm is heated to 700-1000 °C, and difluoromethane (HFC-32) is introduced to react with ammonia gas, and the moles of difluoromethane and ammonia gas are controlled The ratio is 1:1, the residence time of difluoromethane and ammonia in the reactor is 15 seconds, and the reaction pressure is normal pressure. After the reaction product is washed with water, washed with alkali, dried to remove water, and reacted for 10 hours, the gas phase sample is taken for analysis. Gas chromatography detection, the results are shown in Table 8.

[0040] Table 3 Reaction results of co-pyrolysis of difluoromethane and ammonia

[0041]

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Abstract

The invention discloses a method for preparing a fluorinated compound CH2F-R (R is H or CF3) through difluoromethane pyrolysis. According the method, the fluorinated compound is obtained through a gas-phase reaction between difluoromethane and CH4, NH3, H2O or H under the circumstance that no catalyst exists. The following reaction conditions of the method are achieved: the reaction pressure is 0.1-1.5 MPa; the reaction temperature is 700-1000 DEG C; the mole ratio of difluoromethane to any one or more of CH4, NH3, H2O and H is 1:(0-40); and the residence time is 0.1-50 s. The method disclosed by the invention has the advantages that the raw material, namely difluoromethane, is easy to obtain; no catalyst needs to use; the operation and the control are easy; and the experimental repeatability is high.

Description

technical field [0001] The invention relates to a method for preparing fluorine-containing compound CH by pyrolysis of methane 2 F-R (R=H or -CF 3 ) method, especially related to a separate pyrolysis of difluoromethane, or difluoromethane and CH 4 , NH 3 、H 2 Any one or several of O and hydrogen undergo co-pyrolysis to prepare the fluorine-containing compound CH 2 F-R (R=H or -CF 3 )Methods. Background technique [0002] 1,1,1,2-Tetrafluoroethane is an important environmentally friendly refrigerant. Currently, there are hundreds of synthetic routes for 1,1,1,2-tetrafluoroethane. [0003] The literature (European Journal of Organic Chemistry, 1999, 11:3151-3153) uses 1,1-difluoroethylene as raw material to react with xenon difluoride to obtain HFC-134a, and its conversion rate is 92%. [0004] Literature (Journal of Catalysis, 164:378-386) obtained HFC-134a by hydrogenolysis of 1,1-dichlorotetrafluoroethane, and its conversion rate was 83%. [0005] Document (Journal...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C17/00C07C17/26C07C19/08C07C21/18C07C21/185C07C9/04C07C5/02
CPCC07C5/02C07C17/00C07C17/26C07C19/08C07C21/18C07C21/185C07C9/04
Inventor 权恒道张呈平张小玲贾晓卿庆飞要
Owner BEIJING INSTITUTE OF TECHNOLOGYGY