Method for preparing trichloroethylene

A technology for trifluoroethylene and trifluorovinyl bromide, which is applied in the field of preparing trifluoroethylene, can solve the problems of short catalyst life, low conversion rate, difficult collection, separation and purification of products, etc., and achieves easy separation and purification, and product selection. high sex effect

Inactive Publication Date: 2012-03-14
CHANGSHU 3F ZHONGHAO NEW CHEM MATERIALS +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The trifluoroethylene yield of this process is improved, but there are problems such as short catalyst life, product is difficult to collect and separation and purification; (3) French patent (15-16) reports to be raw material with HFC-134a, aluminum fluoride is catalyst, Preparation of trifluoroethylene by catalytic dehydrofluorination in the range of 400-600°C
There is the low problem of HFC-134a transformation rate in this technique; (4) J...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Put 50g of activated zinc powder into a dry 500ml four-necked flask, vacuumize it and replace it with high-purity nitrogen, repeat three times to keep the flask in a nitrogen atmosphere. Add 190ml of N,N-dimethylformamide, heat to 50°C under stirring, add dropwise a mixed solution of 105g of 1,1,2-tribromotrifluoroethane and 110ml of N,N-dimethylformamide, and Keep the reaction temperature at 50-70°C. After the dropwise addition, the temperature was raised to 80-90° C. and maintained for 4 hours. Cool the reaction system to 0-5°C and add 30g of deionized water dropwise. After the generated gas passes through the -25°C cold trap, the liquid nitrogen cold trap collects the gas generated by the reaction, and actually collects 9.7g of liquid, which is detected by gas chromatography. The purity of vinyl fluoride is 83.2%. Based on the actual collected products, the yield of trifluoroethylene was 36.7%.

Embodiment 2

[0049] Put 12g of activated magnesium powder into a dry 500ml four-necked flask, vacuumize it and replace it with high-purity nitrogen, repeat three times to keep the flask in a nitrogen atmosphere. Add 250ml N,N-dimethylformamide, heat to 70°C under stirring, add dropwise a mixed solution of 65g 1,1,2-tribromotrifluoroethane and 140ml N,N-dimethylformamide, and The reaction temperature was maintained at 70-75°C. After the dropwise addition, the temperature was raised to 85-90° C. and maintained for 3 hours. Cool the reaction system to 5-20°C and add 20g of deionized water dropwise. After the generated gas passes through the -25°C cold trap, the liquid nitrogen cold trap collects the gas generated by the reaction, and actually collects 6.5g of liquid, which is detected by gas chromatography. The purity of vinyl fluoride is 89.1%. Calculated based on the actually collected products, the yield of trifluoroethylene was 34.87%.

Embodiment 3

[0051]Put 25g of activated zinc powder into a dry 500ml four-neck flask, vacuumize it and replace it with high-purity nitrogen, repeat three times to keep the flask in a nitrogen atmosphere. Add 65ml of N,N-dimethylformamide, heat to 90°C under stirring, add dropwise a mixed solution of 50g of 1,1,2-tribromotrifluoroethane and 260ml of N,N-dimethylformamide, and Keep the reaction temperature at 75-90°C. After the dropwise addition, the temperature was raised to 85-90° C. and maintained for 1 hour. Cool the reaction system to 20-30°C and add 20g of deionized water dropwise. After the generated gas passes through the -25°C cold trap, the liquid nitrogen cold trap collects the gas generated by the reaction, and actually collects 7.3g of liquid, which is detected by gas chromatography. The purity of vinyl fluoride is 88.5%. Based on the actual collected products, the yield of trifluoroethylene was 56.9%.

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Abstract

The invention discloses a method for preparing trichloroethylene, which is characterized in that: with the existence of organic solvent, 1,1,2-tribromo trifluoroethane is adopted to be reacted with metal dehalogenating agent to generate metallorganics of trichloroethylene-base bromide, then water is dropped into the metallorganics to obtain trichloroethylene gas, the metal dehalogenating agent is metal zinc powder or metal magnesium powder, and the organic solvent is nonprotonic polarity polar solvent. The product produced through the method has high selectivity and is easy to separate and purify.

Description

technical field [0001] The invention relates to a method for preparing trifluoroethylene, in particular to a method for preparing trifluoroethylene by using 1,1,2-tribromotrifluoroethane as a raw material. Background technique [0002] Trifluoroethylene is an important fluorine-containing polymer monomer, which can be synthesized with other compounds such as environmentally friendly cleaning agent hydrofluoroether, refrigerants, high-grade fabric finishing agents, fluorine-bromine oil and other fluorine-containing compounds. Copolymers of vinyl fluoride have unusual piezoelectric properties and play an important role in the artificial synthesis of human organs. However, trifluoroethylene has a low boiling point, is easy to self-polymerize and explode, has high danger, and is difficult to transport and store for a long time. At present, there is very little research on the preparation of trifluoroethylene in China, and no mature production technology and process have been pr...

Claims

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Application Information

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IPC IPC(8): C07C21/18C07C17/23
Inventor 王益王其明沈德新沈雪忠龙湘犁钱刚
Owner CHANGSHU 3F ZHONGHAO NEW CHEM MATERIALS
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