Gas phase purification method for 1,1-difluoroethane

A technology of difluoroethane and purification method, which is applied in 1 field and can solve problems such as not being able to meet high purity requirements

Inactive Publication Date: 2011-06-22
SINOCHEM LANTIAN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method can basically purify 1,1-difluoroethane to more than 99.9%, the total olefin content is more than tens or even hundreds of ppm, and the content of vinyl chloride is more than 5 ppm, which still cannot meet the requirements of high-purity 1,1. - Requirements for difluoroethane

Method used

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  • Gas phase purification method for 1,1-difluoroethane
  • Gas phase purification method for 1,1-difluoroethane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Add 17.5g (33ml) of silica gel to the reaction tube, specific surface area: 750-850m 2 / g, average pore diameter: 22- Heating keeps the temperature in the reaction tube at about 50°C and the pressure at about 2 atmospheres, feeds chlorine gas into the reaction tube at a flow rate of 0.0) L / min for 2 hours, closes the valve of the reaction tube, and seals it for 2 hours. Heating was stopped, the valve was opened, the reaction tube was purged with nitrogen, vacuumized, and the reaction tube was naturally cooled to normal temperature. The crude product of 1,1-difluoroethane containing vinyl chloride was passed into the reaction tube at a speed of 0.1L / min. The content of 1,1-difluoroethane was 99.992%, and the content of vinyl chloride was 0.00201%. The olefin content was 0.00219%, and the pressure during the adsorption process was kept at about 5 atmospheres. Samples were taken after 20, 40 and 60 minutes for gas chromatography analysis. The results are shown in Table 1...

Embodiment 2

[0030] Add 140g (265ml) molecular sieve into the reaction tube, the specific surface area is 830-860m 2 / g, average pore diameter: 14- Heating to keep the temperature in the reaction tube at about 350°C, and the pressure at about 5 atmospheres, feed chlorine gas into the reaction tube at a flow rate of 0.05 L / min for 3 hours, close the valve of the reaction tube, and seal it for 2 hours. Heating was stopped, the valve was opened, the reaction tube was purged with nitrogen, vacuumized, and the reaction tube was naturally cooled to normal temperature. The crude 1,1-difluoroethane containing vinyl chloride is introduced into the reaction tube at a speed of 0.1 L / min. The content of 1,1-difluoroethane is 99.992%, the content of vinyl chloride is 0.00201%, and the total olefins The content is 0.00219%, and the pressure in the adsorption process is maintained at about 3 atmospheres. Samples are taken after 20, 40 and 60 minutes for gas chromatography analysis, and the results are ...

Embodiment 3

[0032] Add 17.5g (33ml) zeolite to the reaction tube, the specific surface area is 620-750m 2 / g, average pore diameter 22- Heating to keep the temperature in the reaction tube at about 350°C, and the pressure at about 8 atmospheres, feed chlorine gas into the reaction tube at a flow rate of 0.05 L / min for 10 hours, close the valve of the reaction tube, and seal it for 2 hours. Heating was stopped, the valve was opened, the reaction tube was purged with nitrogen, vacuumized, and the reaction tube was naturally cooled to normal temperature. The crude product of 1,1-difluoroethane containing vinyl chloride was passed into the reaction tube at a speed of 0.1L / min. The content of 1,1-difluoroethane was 99.992%, and the content of vinyl chloride was 0.00201%. The olefin content was 0.00219%, and the pressure during the adsorption process was maintained at about 8 atmospheres. Samples were taken after 20, 40 and 60 minutes for gas chromatography analysis. The results are shown in ...

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Abstract

The invention relates to a method for purifying 1,1-difluoroethane by gas phase absorption separation. In the method, by using one or more of silica gel, activated aluminum oxide, activated magnesia and aluminosilicate absorbents and carbon absorbents, preferably an absorbent with a Brunauer-Emmett-Teller (BET) specific surface area more than or equal to 400m<2> / g and a single-point average aperture of 5 to 30 angstroms, the 1,1-difluoroethane content in a 1,1-difluoroethane coarse product containing vinyl chloride can be improved to over 99.99 percent, the total olefin content is reduced to below tens of ppm or even below 10ppm, and the vinyl chloride content is reduced to below several ppm or even below 1ppm. The 1,1-difluoroethane can be used alone or in combination with other materials as a low-temperature refrigerator, a foaming agent, a propellant, an etching gas, a cleaning agent or an intermediate of other fluorocarbons.

Description

technical field [0001] The invention relates to a method for purifying 1,1-difluoroethane, especially a gas-phase adsorption separation method. Background technique [0002] 1,1-difluoroethane (HFC-152a), boiling point at normal pressure -24.023°C, ODP value (ozone depletion potential value) is 0, GWP value (greenhouse effect potential value) is 0.03, is an excellent ozone depleting Substances (ODS) substitutes that can be used alone or mixed with other materials as cryogenic refrigerants, blowing agents, propellants, etching gases, cleaning agents or as intermediates for other fluorocarbons. [0003] The production methods of 1,1-difluoroethane (HFC-152a) mainly include acetylene method and vinyl chloride method. When vinyl chloride is used as raw material, 1,1-difluoroethane (HFC-152a) -152a) In addition to the product, there are unreacted vinyl chloride, hydrogen fluoride, vinyl fluoride and other organic by-products such as 1-fluoro-1-chloroethane). Most of the by-prod...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C19/08C07C17/389B01J20/34
Inventor 潘彦郭荔赵卫娟柳彩波洪慧能黄友良
Owner SINOCHEM LANTIAN
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