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Method for preparing vinylidene fluoride monomer

A technology of vinylidene fluoride and monomers, which is applied in the field of vinylidene fluoride preparation by the cracking process of water dilution method, which can solve the problems of low production efficiency of vinylidene fluoride, easy blockage of pipelines, and many by-products, so as to extend the shutdown maintenance period, The effect of reducing production cost and improving reaction rate

Active Publication Date: 2015-04-29
RUYUAN DONGYANG LIGHT FLUORINE RESIN CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The VDF prepared by this method has a high purity. Without rectification treatment, the VDF can generally reach more than 95%, and the highest can reach 98.7%. And other issues
[0004] For the preparation methods of the above-mentioned vinylidene fluoride monomers, due to the cracking reaction itself, it is easy to generate carbon knots and easily block the pipeline. Low alkane conversion rate, high impurity content in cracked gas, low selectivity, high recovery cost of unreacted 1,1-difluoro-1-chloroethane, etc., which lead to low production efficiency of cracking to prepare vinylidene fluoride, and frequent shutdown Maintenance equipment, coke and carbon removal

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Vacuumize the cracking device system to replace nitrogen 5 times, check that the oxygen content in the kettle is lower than 20ppm, fill the system with nitrogen to make the system slightly positive pressure, deionized water and 1,1-difluoro-1-chloroethane respectively pass through the preheating furnace After mixing into the cracking tube, the temperature of the deionized water preheating furnace is 650 °C, and 1,1-difluoro-1-chloroethane is passed into the preheating furnace at a rate of 20 L / s. 2 The feed rate of O is 5ml / s, the temperature of the preheating furnace is set at 300°C, the cracking pressure is controlled at 0.05MPa, and the temperature of the cracking furnace is controlled at 650°C. After passing through the cracking tube, the gas passes through the buffer chamber, condenser, and sodium hydroxide respectively. Acid removal tank, freezing and water removal device to obtain cracked gas. The test results of selectivity and conversion are shown in Table 1. ...

Embodiment 2

[0024] Vacuumize the cracking device system to replace nitrogen 5 times, check that the oxygen content in the kettle is lower than 20ppm, fill the system with nitrogen to make the system slightly positive pressure, deionized water and 1,1-difluoro-1-chloroethane respectively pass through the preheating furnace After mixing into the cracking tube, the temperature of the deionized water preheating furnace is 700 °C, and 1,1-difluoro-1-chloroethane is passed into the preheating furnace at a rate of 20 L / s. 2 The feed rate of O is 10ml / s, the temperature of the preheating furnace is set at 350°C, the cracking pressure is controlled at 0.05MPa, and the temperature of the cracking furnace is controlled at 700°C. After passing through the cracking tube, the gas passes through the buffer chamber, condenser, and sodium hydroxide respectively Acid removal tank, freezing and water removal device to obtain cracked gas. The test results of selectivity and conversion are shown in Table 1. ...

Embodiment 3

[0026] Vacuumize the cracking device system to replace nitrogen 5 times, check that the oxygen content in the kettle is lower than 20ppm, fill the system with nitrogen to make the system slightly positive pressure, deionized water and 1,1-difluoro-1-chloroethane respectively pass through the preheating furnace After mixing into the cracking tube, the temperature of the deionized water preheating furnace is 780 ° C, and 1,1-difluoro-1-chloroethane is passed into the preheating furnace at a rate of 20 L / s. 2 The feed rate of O is 15ml / s, the temperature of the preheating furnace is set at 350°C, the cracking pressure is controlled at 0.10MPa, and the temperature of the cracking furnace is controlled at 780°C. After passing through the cracking tube, the gas passes through the buffer chamber, condenser, and sodium hydroxide respectively. Acid removal tank, freezing and water removal device to obtain cracked gas. The test results of selectivity and conversion are shown in Table 1....

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PUM

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Abstract

The invention relates to a method for preparing a vinylidene fluoride monomer. The method is characterized by comprising the following steps: preheating and mixing water and 1,1-difluoro-1-chloroethane and feeding the mixture into a cracking tube, quenching reacted cracking gas, removing HCl, drying and feeding the dried gas to a rectifying tower to obtain the high-purity vinylidene fluoride monomer. By the method, the problems of carbon deposition, clogging of a pipeline and the like can be decreased, the selectivity and reaction efficiency can be effectively improved, the reaction temperature is decreased and thus the energy consumption can be reduced, the energy consumption is substantially reduced and the pollution is decreased.

Description

technical field [0001] The invention relates to a method for preparing vinylidene fluoride, in particular to a method for preparing vinylidene fluoride through a water dilution method cracking process. Background technique [0002] Vinylidene fluoride, referred to as VDF, is mainly used for homopolymerization or copolymerization with other monomers to produce polyvinylidene fluoride. At present, a lot of research has been done on the preparation process of vinylidene fluoride monomer. Different processes are used to prepare it according to different raw materials. In industry, difluorochloroethane (R142b) is often used as raw material. Prepared by cleavage reaction in the tube. Patent CN101003460 uses nitrogen to dilute the reaction gas and a U-shaped series reaction tube, and the volume ratio of high-purity nitrogen to R142b is 0.5:1.0 to input into the cracking tube for reaction. Although the conversion rate of VDF increased by 5% compared with that before the improvemen...

Claims

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Application Information

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IPC IPC(8): C07C21/18C07C17/25
Inventor 凌志华李运如肖凤祥
Owner RUYUAN DONGYANG LIGHT FLUORINE RESIN CO LTD
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