Technique for preparing monochlorodifluoromethane by decomposing trifluoromethane

A technology for difluoromonochloromethane and monofluorodichloromethane is applied in the field of trifluoromethane cracking to prepare difluoromonochloromethane, and achieves the effects of good economic value, less by-products, great operational feasibility and safety

Active Publication Date: 2013-12-25
CHANGSHU 3F ZHONGHAO NEW CHEM MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method can be seen in the example of the co-cracking of trifluoromethane and HCFC-22. The conversion rate of HCFC-22 is 100%, but the yield of pentafluoroethane is 60%, and 4

Method used

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  • Technique for preparing monochlorodifluoromethane by decomposing trifluoromethane

Examples

Experimental program
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Effect test

Embodiment 1

[0022] The catalyst is loaded into the nickel tube reactor and activated by passing hydrogen fluoride at 200°C for 6 hours. HFC-23, monochloromethane and chlorine gas were preheated to 120°C with a molar ratio of 1.0:1.0:1.0, respectively, and put into a nickel tube reactor at 150°C, with a residence time of 5s. A sample was taken one hour after feeding, and the mixed product was analyzed using GC / MS (Gas Chromatography / Mass Spectrometry) and the results obtained were: CF3H40.2%, CCl 3 H41.5%, CHF 2 Cl9.1%, CHCl 2 F9.2%.

Embodiment 2-4

[0024] The reaction temperatures of the nickel tubes are 200°C, 250°C, and 350°C respectively, and the rest of the conditions are the same as in Example 1. The mixed raw materials were put into the reaction and sampled after one hour, and the mixed products were analyzed by GC / MS (gas chromatography / mass spectrometry). The results obtained are shown in the table 1.

Embodiment 5-8

[0026] The molar ratios of HFC-23 and dichloromethane are 0.5, 1.25, 2.25, 3.5 respectively, and the molar number of chlorine is the same as that of HFC-23. Preheat to 120°C respectively, put them into a nickel tube reactor at 250°C, and keep The time is 5s. Samples were taken one hour after feeding, and the mixed product was analyzed by GC / MS (gas chromatography / mass spectrometry). The results obtained are shown in Table 1.

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Abstract

The invention provides a technique for preparing monochlorodifluoromethane by decomposing trifluoromethane. The technique comprises the steps of: feeding the raw materials trifluoromethane and methane chloride into a reactor filled with a catalyst in the mol ratio of 0.1-10, and carrying out a decomposition reaction at a temperature ranging from 150 to 350 DEG C for 3-30 seconds to obtain a mixture of trifluoromethane, methane chloride, dichloromonofluoromethane and monochlorodifluoromethane; obtaining monochlorodifluoromethane directly through separation, reacting dichloromonofluoromethane separated out with hydrogen fluoride to produce monochlorodifluoromethane, and separating out and recovering trifluoromethane and methane chloride in the mixture as the reaction mixture continuously. The method has the advantage that the harm on the environment caused by trifluoromethane emission is greatly avoided.

Description

technical field [0001] The invention relates to a process for preparing difluorochloromethane, in particular to a process for preparing difluorochloromethane by cracking trifluoromethane. Background technique [0002] Trifluoromethane (CF3H, HFC-23) is a by-product of the reaction of HF and chloroform to generate chlorodifluoromethane (HCFC-22), and its content in the generated HCFC-22 is less than about 3wt%, but due to HCFC- 22 itself is the main source for the manufacture of perfluoroolefins such as tetrafluoroethylene (TFE). The global annual production of HCFC-22 is very large, and the annual production of trifluoromethane reaches tens of thousands of tons. Trifluoromethane is a greenhouse gas with a very high global warming potential and a long lifespan. The by-product trifluoromethane needs to be utilized or treated to avoid environmental problems caused by emission. [0003] At present, the treatment methods of trifluoromethane are divided into two types: reuse and ...

Claims

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Application Information

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IPC IPC(8): C07C19/10C07C17/20
CPCY02P20/40
Inventor 司林旭王寅洁沈达陈庭雨
Owner CHANGSHU 3F ZHONGHAO NEW CHEM MATERIALS
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