Method for preparing fluorinated compound CFR1=CFR2 (R1, R2=F or -CF3) through trifluoromethane thermolysis

Abstract

The invention discloses a method for preparing a fluorinated compound CFR1=CFR2 (R1, R2=F or -CF3) through trifluoromethane thermolysis. The method comprises the following steps that under the condition of no catalyst, trifluoromethane takes a gas phrase reaction with CH4, NH3, H2O or hydrogen gas to obtain the fluorinated compound under the reaction conditions that the reaction pressure is 0.1 to 1.5 MPa; the reaction temperature is 700 to 1000 DEG C; the mol ratio of the trifluoromethane to any one or several kinds of materials of CH4, NH3, H2O or hydrogen gas is (1:0) to (1:40); and the dwell time is 0.1 to 50s. The method provided by the invention has the advantages that the raw materials can be easily obtained; a catalyst does not need to be used; the operation and the control are easy; in addition, the experiment repeatability is high; and meanwhile, the conversion and reutilization of HFC-23 are well realized.

Description

technical field [0001] The invention relates to a fluorine-containing compound CFR prepared by pyrolysis of trifluoromethane 1 =CFR 2 (R 1 , R 2 =F or -CF 3 ) method, relate in particular to a kind of pyrolysis of trifluoromethane alone, or trifluoromethane and CH 4 , NH 3 , H 2 Co-pyrolysis of any one or several of O and hydrogen to prepare fluorine-containing compound CFR 1 =CFR 2 (R 1 , R 2 =F or -CF 3 )Methods. Background technique [0002] Trifluoromethane (HFC-23), one of the six high greenhouse gases listed in the 2010 "Kyoto Protocol", its GWP 100 A value of 12400 gives an atmospheric lifetime of 222 years. The Kyoto Protocol controls the emissions of all hydrofluorocarbons (HFCs). Therefore, it is extremely important to study the elimination or transformation and utilization of HFC-23. At present, plasma or high-temperature incineration is generally used to eliminate HFC-23, but it only reduces the harm to the environment, and also emits other toxic g...

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Problems solved by technology

[0006] The above-mentioned technology has the following defects: (1) Generally speaking, at a high temperature above 800°C, the structure of common catalysts is prone to collapse or the crystal form undergoes serious changes or is already in a molten state, resulting in the failure of the reaction to proceed normally; (2) using A large amount of non-condensable nitrogen gas is used as a diluent gas, which increases the burden and difficulty of separation of reaction products

In addition, the co-pyrolysis of trifluoromethane and ammonia or water to prepare fluorine-containing compounds has not been reported in public literature

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