Preparation method of 1,1-difluoroethylene

A technology of ethylene difluoride and chloroethane, which is applied in the field of preparation of 1,1-ethylene fluoride, can solve the problems of unindustrialization of catalytic cracking, poor catalyst stability and service life, etc., achieve high purity, reduce production and Dealing with costs and preparing green effects

Active Publication Date: 2019-01-11
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although catalytic cracking has many advantages, it also has its disadvantages, especially the poor stability and life of the catalyst is the main reason why catalytic cracking cannot be industrialized

Method used

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  • Preparation method of 1,1-difluoroethylene
  • Preparation method of 1,1-difluoroethylene
  • Preparation method of 1,1-difluoroethylene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] First, take 0.01 mol of each of the two transition metal nitrates and put them into a container, and add 100 mL of water. After mixing and stirring evenly, add 0.04-0.06mol solid NH 4F (according to the two metals can form precipitate required F - Calculation) to form a precipitate, and continue to stir for 2h before filtering. The solid obtained after filtration was dried at 110° C. for 12 hours, and calcined at 500° C. for 4 hours to obtain a composite catalyst of transition metal fluoride.

[0030] Then, the obtained composite catalyst catalyzes the removal of HCl from 1,1-difluoro-1-chloroethane to prepare vinylidene fluoride. The reaction is carried out in a plug-flow tube reactor. The reaction tube of the plug-flow tube reactor adopts a Ni tube with an inner diameter of 20mm and a length of 800mm. The composite catalyst is packed into the plug-flow tube reactor. and placed in a heating furnace to heat up to 350°C for reaction. The reaction pressure is normal p...

Embodiment 2

[0035] First, take 0.01 mol of each of the two alkaline earth metal nitrates and put them into a container, and add 100 mL of water. After mixing and stirring evenly, add 0.04mol solid NH 4 F formed a precipitate and was filtered after continued stirring for 2 h. The solid obtained after filtration was dried at 110° C. for 12 hours, and calcined at 500° C. for 4 hours to obtain a composite catalyst of alkaline earth metal fluoride.

[0036] Then, the obtained composite catalyst catalyzes the removal of HCl from 1,1-difluoro-1-chloroethane to prepare vinylidene fluoride. The reaction is carried out in a plug-flow tube reactor. The reaction tube of the plug-flow tube reactor adopts a Ni tube with an inner diameter of 20mm and a length of 800mm. The composite catalyst is packed into the plug-flow tube reactor. and placed in a heating furnace to heat up to 350°C for reaction. The reaction pressure is normal pressure.

[0037] Before the reaction, N 2 (airspeed is 1000h -1 ),...

Embodiment 3

[0041] First, take 0.01mol each of the two alkaline earth metal hydroxides and add them to the grinding, mix and stir evenly, then add 0.02mol (NH 4 ) 2 SiF 6 , and continue grinding for at least 0.5h, the obtained solid was dried at 110°C for 12h, and calcined at 500°C for 4h to obtain a composite catalyst of alkaline earth metal fluoride.

[0042] Then, the obtained composite catalyst catalyzes the removal of HCl from 1,1-difluoro-1-chloroethane to prepare vinylidene fluoride. The reaction is carried out in a plug-flow tube reactor. The reaction tube of the plug-flow tube reactor adopts a Ni tube with an inner diameter of 20mm and a length of 800mm. The composite catalyst is packed into the plug-flow tube reactor. and placed in a heating furnace to heat up to 350°C for reaction. The reaction pressure is normal pressure.

[0043] Before the reaction, N 2 (airspeed is 1000h -1 ), the temperature of the composite catalyst bed was raised from room temperature to 200°C at a...

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Abstract

The invention discloses a preparation method of 1,1-difluoroethylene. The preparation method comprises following steps: a composite catalyst is introduced into a tubular reactor, 1, 1-difluoro-1-chloroethane or 1, 1-difluoro-2-chloroethane is taken as a raw material and is introduced into the tubular reactor for gas phase catalytic cracking so as to obtain 1,1-difluoroethylene. The composite catalyst is a metal composite fluoride. The method is low in reaction temperature, high in product selectivity, high in yield, mild in operation technical conditions, and simple in operation, and the reproducibility of the adopted catalyst is high.

Description

technical field [0001] The invention relates to a preparation method of 1,1-difluoroethylene. Background technique [0002] 1,1-Difluoro-1-chloroethane (HCFC-142b, or R142b) is a colorless gas at room temperature with a slight aroma and is easily soluble in oil, but hardly soluble in water. HCFC-142b is an important organic intermediate, used in various fields such as refrigerants, blowing agents, etc., but it is mainly used to produce polyvinylidene fluoride (PVDF) monomer, 1,1-difluoro Vinyl (VDF). So far, the production scale of vinylidene fluoride among fluorine-containing monomers is second only to tetrafluoroethylene, and it is widely used in various fields. 1,1-Difluoroethylene (also known as vinylidene fluoride) is one of the important varieties of fluorine-containing olefins, mainly used in the production of polyvinylidene fluoride resin, fluororubber and fluorine-containing copolymers such as vinylidene fluoride-hexafluoropropylene, Vinylidene fluoride-vinyliden...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C17/25C07C21/18B01J27/138B01J27/132B01J37/03
CPCB01J27/132B01J27/138B01J37/0036B01J37/031C07C17/25C07C21/18
Inventor 韩文锋王志昆刘兵李西良唐浩东李瑛刘化章
Owner ZHEJIANG UNIV OF TECH
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