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Method for producing metafluoroethylene by pyrolysis of difluoro-chloroethane

A technology of difluoro-chloroethane and vinylidene fluoride, which is applied in the fields of dehydrohalogenation preparation, organic chemistry, etc., can solve the problems of unstable product quality, high quality requirements for operators, and high requirements for instrument performance, so as to improve continuous operation Cycle time, good quality stability, and low property requirements

Inactive Publication Date: 2003-07-09
ZHONGHAO CHENGUANG RES INST OF CHEMICALINDUSTRY CO LTD
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this separation treatment method has the characteristics of a short process, it has a low dehydration rate, and the water content of the dehydrated mixture is generally in the range of 300-400PPm; online monitoring is required during the separation treatment process, and its performance requirements are high. , large investment, high requirements on the quality of operators, once out of control, it is easy to cause the packing in the tower to freeze, and the product quality is unstable, and only vinylidene fluoride with a purity of 99.9% can be obtained
[0003] Therefore the above-mentioned background technology exists that conversion rate and selectivity are all low, and or the cracking tube is easy to coke and block, the continuous production cycle is short, or the reaction speed is difficult to control, and side reactions easily occur; and the separation process control instrument investment is large, and the water content of the mixture is relatively high. High, high quality requirements for operators, poor quality stability and purity, etc.

Method used

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  • Method for producing metafluoroethylene by pyrolysis of difluoro-chloroethane
  • Method for producing metafluoroethylene by pyrolysis of difluoro-chloroethane
  • Method for producing metafluoroethylene by pyrolysis of difluoro-chloroethane

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Embodiment 1

[0025] Reactor 4 in this embodiment adopts an adiabatic tubular reactor with a pipe diameter of Φ22×2. Its technological process is:

[0026] A. Firstly, the superheated steam is heated to 890°C through the hot steam heating device, and the material difluorochloroethane is heated to 250°C through the difluorochloroethane preheating device;

[0027] B. Input the above-mentioned superheated steam into the mixing device 3 at 22500mol / h and preheated difluorochloroethane at 1250mol / h and mix evenly, and the dilution ratio is 18;

[0028] C. Cracking reaction: heat and crack the uniformly mixed superheated steam and materials in the externally heated tubular reactor 4, the reaction residence time is 0.02s, the reactor inlet temperature is 840°C, and the outlet temperature is 780°C.

[0029] D. The above-mentioned cracking reactant is input into the coil cooling device and rapidly cooled to 160°C.

[0030] E. Separation treatment:

[0031] a. Initial dehydration: The mixture quen...

Embodiment 2

[0041] The reactor in this embodiment adopts an externally heated tubular reactor with a pipe diameter of φ14×2.

[0042]The feed rate of difluoro-chloroethane is 1500mol / h, preheated to 400°C, the dilution ratio is 13, the superheated steam temperature is 700°C, the materials are mixed into the reactor 4, and the reactor is continued to be heated so that the outlet temperature of the reactor reaches 680°C , The reaction residence time is 0.1s (seconds). All the other processes are the same as in Example 1.

[0043] In this example, the conversion rate of vinylidene fluoride is 92%, the selectivity is 99.4%, and the purity of vinylidene fluoride separated by rectification is ≥99.99%.

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Abstract

The method for producing vinylidene fluoride by using difluorine-chloroethane includes the following steps: adopting superheated steam, mixing it with difluorine-chloroethane and making them produce cracking reaction in tube reactor, then making the crackate undergo the processes of quenching, low-pressure condensation dewatering, drying treatment, removing high boiler, removing liquid component, rectifying vinylidene fluoride and recovering vinylidene fluoride and difluorine-chloroethane from residue so as to implement goal of said invention. The invented difluorine-chloroethane conversion rate can be up to 95%, selectivity of vinylidende fluoride is greater than 99% and its vinylidene fluoride monomer purity is greater than or equal to 99.99%.

Description

technical field [0001] The invention belongs to a method for preparing vinylidene fluoride, in particular to a method for producing vinylidene fluoride by cracking difluorochloroethane. Background technique [0002] Conventionally, the process methods for producing vinylidene fluoride monomer by using difluoro-chloroethane (international general code: HCFC-142b) include: 1. Use an empty tube to crack in the temperature range of 700-1000 ° C. The conversion rate and selection of this method The properties are not ideal, and the cracking tube is easy to coke and block, and the continuous production cycle is short; 2. Adding an accelerator during thermal cracking; in 1953, the American Allied Company proposed that a certain amount of CCl should be added to the thermal cracking of HCFC-142b 4 As an accelerator, the reaction temperature can be lowered to 550°C, and Cl 2 As a promoter, although the conversion rate can reach more than 85%, the selectivity is only 87.5%; 3. Catalyt...

Claims

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Application Information

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IPC IPC(8): C07C17/25C07C21/18
Inventor 张在利曾本忠曾子敏喻崇权张德波
Owner ZHONGHAO CHENGUANG RES INST OF CHEMICALINDUSTRY CO LTD
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