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Preparation method of terephthaloyl chloride

A technology for terephthaloyl chloride and terephthalic acid, which is applied in the field of preparation of terephthaloyl chloride, can solve the problems of instability of N,N-dimethylformamide, difficult separation of purity, long time and the like, and achieves The effect of easy exhaust, maintaining high purity and low cost

Inactive Publication Date: 2015-04-01
SHANDONG KAISHENG NEW MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method is unstable due to N,N-dimethylformamide, SOCl 2 The reaction generates (chloromethylene) dimethyl ammonium chloride, which makes it difficult to separate and has low purity. After repeated vacuum distillation, the product purity can reach more than 99%.
The chlorination agent in the phosphorus pentachloride method is solid phosphorus pentachloride, and it is relatively difficult to add materials. In addition, phosphorus pentachloride is easy to absorb water, and the generation of hydrogen chloride affects the accuracy of the feeding ratio, and terephthalic acid itself is also It is solid, the two are not easy to mix evenly, and the operation is inconvenient
Phosphorus trichloride method requires high reaction temperature, long time, complicated process operation conditions, and the purification of the by-product phosphorus oxychloride, which not only corrodes the equipment, but also increases the production cost.
The process route of phosgene method requires special generation of phosgene or purchase of phosgene. Phosgene is a highly toxic product. Solvents need to be used in the reaction, and the by-product is also a gas. It is easy to cause phosgene to be discharged along with the by-product, and the requirements for safety and protection are very high. , in addition to increase the solvent recovery device, so that the production cost increased significantly

Method used

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  • Preparation method of terephthaloyl chloride
  • Preparation method of terephthaloyl chloride

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] (1) Take 100g of p-xylene, under the irradiation of LED light source with a wavelength of 380-390nm, pass 481.5g of chlorine gas into it at 130°C, and react for 8 hours to obtain 1,4-bis(trichloromethyl)benzene Crude product 289.6g, chromatographic content is 92.0%;

[0026] (2) The 1,4-bis(trichloromethyl)benzene crude product obtained in step (1) and 144.8 g of terephthalic acid were added to the reaction flask, and under the catalysis of 0.145 g of zinc chloride, at 120° C. The reaction was carried out for 8 hours, until no hydrogen chloride gas was released, and the obtained reaction solution was rectified under reduced pressure to obtain 363.71 g of terephthaloyl chloride, the chromatographic content was 99.93%, the melting point was 82.3 ° C, and the total product yield was 95.1% (calculated by p-xylene). ).

Embodiment 2

[0028] (1) Take 100g of p-xylene, under the irradiation of LED light source with a wavelength of 420-430nm, pass 521.6g of chlorine gas into it at 140°C, and react for 9 hours to obtain 1,4-bis(trichloromethyl)benzene Crude product 290.27g, chromatographic content is 95.17%;

[0029] (2) 1,4-bis(trichloromethyl)benzene crude product obtained in step (1) and 153.8g of terephthalic acid were added to the reaction flask, and under the catalysis of 0.461g of ferric chloride, at 130°C The reaction was carried out for 7 hours until no hydrogen chloride gas was released, and the obtained reaction solution was rectified under reduced pressure to obtain 371.40 g of terephthaloyl chloride, the chromatographic content was 99.91%, the melting point was 82.2°C, and the product yield was 97.1% (calculated by p-xylene) .

Embodiment 3

[0031] (1) Take 100g of p-xylene, under the irradiation of LED light source with a wavelength of 470-480nm, pass 561.7g of chlorine gas into it at 150°C, and react for 10 hours to obtain 1,4-bis(trichloromethyl)benzene Crude product 290.34g, chromatographic content is 96.0%;

[0032] (2) The 1,4-bis(trichloromethyl)benzene crude product obtained in step (1) and 162.6 g of terephthalic acid were added to the reaction flask, and under the catalysis of 0.813 g of zinc chloride, at 140° C. React for 6 hours, until no hydrogen chloride gas is released, the gained reaction solution is rectified under reduced pressure to obtain terephthaloyl chloride 375.57g, the chromatographic content is 99.94%, the melting point is 82.5 ° C, and the total product yield is 98.2% (calculated by p-xylene). ).

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Abstract

The invention belongs to the field of organic chemical synthesis and in particular relates to a preparation method of terephthaloyl chloride. The preparation method comprises the following steps: under irradiation of an LED (light-emitting diode) light source, introducing excessive chlorine to p-xylene to react to obtain a 1,4-bis(trichloromethyl)benzene crude product; enabling the 1,4-bis(trichloromethyl)benzene crude product to react with p-phthalic acid in the presence of a catalyst until no hydrogen chloride is released and carrying out vacuum distillation on an obtained reaction liquid to obtain terephthaloyl chloride. The preparation method has the beneficial effects that the preparation method has the advantages of easily obtained raw materials, low cost, easiness in tail gas treatment, and the like and is suitable for industrial production; the melting point, purity and yield of prepared terephthaloyl chloride are respectively 82-83 DEG C, more than 99.9% and more than 95%; any solvent is not needed to be mixed, the catalyst is recycled, and the high purity of the product is kept.

Description

technical field [0001] The invention belongs to the field of organic chemical synthesis, in particular to a preparation method of terephthaloyl chloride. Background technique [0002] Terephthaloyl chloride is an important organic chemical raw material and a raw material for polymers such as polyamide and polyester. It is the monomer of synthetic special fiber, which can be used as aramid fiber and polyamide fiber reinforcing agent. Aramid fiber is a kind of high-performance synthetic fiber. Up to 2 times and 6 times of high-quality steel, used in aircraft, rockets, missiles and bulletproof equipment. [0003] The synthesis process of terephthaloyl chloride using terephthalic acid as raw material is mainly divided into thionyl chloride method, phosphorus pentachloride method, phosphorus trichloride method and phosgene method according to different acid chloride reagents. The thionyl chloride method uses thionyl chloride as the chlorinating agent, terephthalic acid as the r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/60C07C63/30
CPCY02P20/584C07C51/60C07C17/14
Inventor 薛居强张泰铭张聪聪王荣海毕义霞张善民杨德耀宋国城王炼
Owner SHANDONG KAISHENG NEW MATERIALS
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