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Purification method of molecular distillation of bis(trichloromethyl)benzene

A trichloromethyl and molecular distillation technology, which is applied in the field of molecular distillation and purification of bis(trichloromethyl)benzene, can solve the problems of high environmental cost, troublesome condensation or cooling, uneven heating, etc., and achieve short residence time of materials , reduce environmental protection expenditures, and avoid high-temperature coking effects

Active Publication Date: 2016-09-07
FININGS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, the method for preparing bis(chloroformyl)benzene with xylene as a raw material requires further purification of the generated bis(trichloromethyl)benzene, but bis(trichloromethyl)benzene is heat-sensitive, and traditional purification methods , For example, atmospheric distillation, rectification, etc. are separated and purified according to the difference in boiling point of the compound, and need to stay in a high temperature environment for a long time, so that bis(trichloromethyl)benzene will partially polymerize, and these methods are used to purify bis(trichloromethyl)benzene Trichloromethyl) benzene will cause coking problems, resulting in low yield of bis(trichloromethyl) benzene, and the coke at the bottom will cause damage to the equipment on the one hand and need to be cleaned regularly; on the other hand, the coke at the bottom will be harmful to the environment. Harmful, it needs to be handled properly, and the environmental cost is high; although vacuum distillation can reduce the temperature required for separation, the material to be separated must maintain a certain liquid level in the reboiler to generate a static pressure difference, so that the material in the tower kettle The vaporization temperature rises, so sometimes it is difficult to avoid the thermal decomposition of materials; the existence of inert gas is beneficial to the rectification of heat-sensitive materials, but it brings troubles to condensation or cooling
In addition, the material is prone to uneven heating in the reboiler.
In particular, when such substances are heated industrially with metal products equipment for a long time, they are prone to dimerization and are converted into high-boiling impurities, thereby reducing the overall yield of the target product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment １

[0032] Three glass-lined reaction towers with temperature measurement, reflux condenser, LED lamp irradiation device and heating and cooling device are connected in series to form a continuous photochlorination reaction device, in which the glass-lined reaction towers are the first tower, the second tower and the third tower. After the pressure test, leak test, cleaning, drying and other preparatory stages of the reaction device, the original start-up was started, and the feeding amount was gradually increased. After the photochlorination reaction was stabilized, 1,3-bis(methyl)benzene The speed is continuously added to the first tower. The tower temperature of the first tower is controlled at 80°C~120°C by a heating or cooling device. The peak wavelength of the incident light center of the first tower is 460nm. Feed chlorine gas at a flow rate of 135kg / h for continuous chlorination reaction, control the heating or cooling speed so that the temperature of the first tower does ...

Embodiment ２

[0035] Preparation of crude 1,4-bis(trichloromethyl)benzene: Three glass-lined reaction towers with temperature measurement, reflux condenser, LED lamp irradiation device and heating and cooling device are connected in series to form a continuous photochlorination reaction device , wherein the glass-lined reaction towers are the first tower, the second tower and the third tower in turn. After the reaction device has gone through the preparatory stages of pressure test, leak test, cleaning and drying, etc., the original start-up is started, and the feeding amount is gradually increased. After the photochlorination reaction is stable, 1,4-bis(methyl)benzene The speed is continuously added to the first tower. The tower temperature of the first tower is controlled at 80°C~120°C by a heating or cooling device. The peak wavelength of the incident light center of the first tower is 470nm. Feed chlorine gas at a flow rate of 140kg / h for continuous chlorination reaction, control the he...

Embodiment ３

[0038] Preparation of crude 1,3-bis(trichloromethyl)benzene: Three glass-lined reaction towers with temperature measurement, reflux condenser, LED lamp irradiation device and heating and cooling device are connected in series to form a continuous photochlorination reaction device , wherein the glass-lined reaction towers are the first tower, the second tower and the third tower in turn. After the pressure test, leak test, cleaning, drying and other preparatory stages of the reaction device, the original start-up was started, and the feeding amount was gradually increased. After the photochlorination reaction was stabilized, 1,3-bis(methyl)benzene The speed is continuously added to the first tower. The tower temperature of the first tower is controlled at 60°C~120°C by a heating or cooling device. The peak wavelength of the incident light center of the first tower is 405nm. Feed chlorine gas at a flow rate of 142kg / h for continuous chlorination reaction, control the heating or ...

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PUM

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Abstract

The invention discloses a method for purifying bis(trichloromethyl)benzene. Molecular distillation and separation technology is introduced. Firstly, the crude product of bis(trichloromethyl)benzene is pretreated to remove light components; then carry out primary molecular distillation on the pretreated bis(trichloromethyl)benzene to obtain high-purity bis(trichloromethyl)benzene; optionally, further distill the primary molecular distillation The residue was subjected to secondary molecular distillation. The method of the invention solves the problems of easy product polymerization and coking in the purification process of bis(trichloromethyl)benzene, and has the advantages of high product yield, high purity, energy saving, environmental protection and the like.

Description

technical field [0001] The invention relates to a purification method of bis(trichloromethyl)benzene, in particular to a molecular distillation purification method of bis(trichloromethyl)benzene. Background technique [0002] The production of aramid fiber requires high-purity bis(chloroformyl)benzene as the starting material, otherwise the quality of aramid fiber cannot meet the specified requirements. Among the preparation methods of bis(chloroformyl)benzene in the prior art, the most commonly used method is the thionyl chloride method using phthalic acid as a raw material (for example, see CN 102516060A, CN 102344362A). However, 99.99% high-purity phthalic acid is required in this process to obtain satisfactory bis(chloroformyl)benzene, which significantly increases the preparation cost of this route and increases the difficulty of the process. Shanxi Chemical Industry, Vol. 29, No. 1, February 2009, Synthetic process of o-, m-, and terephthaloyl dichlorides. It shows th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C22/04C07C17/383C07C17/38
Inventor 王农跃赵全忠邵建明闻国强
Owner FININGS CO LTD