Preparation method of terephthaloyl chloride

Abstract

The invention is suitable for the field of terephthaloyl chloride preparation, and provides a preparation method of terephthaloyl chloride. The method comprises the following steps that: terephthalic acid, thionyl chloride and a catalyst are added into a reaction tank; a cold circulating water switch on a condenser is switched on, and a tail gas absorption valve is turned on, such that a reflux reaction is started; after the reaction, thionyl chloride is recovered under a kettle liquid temperature of 75 to 100 DEG C; a decolorant with a volume of 2% to 8% of the added terephthalic acid volume is added to an alembic; a feeding valve is opened, a crude product with excess thionyl chloride removed is added to the alembic with the decolorant added; the decolorant is fused with the crude product under a kettle liquid temperature of 80 to 145 DEG C; high purity terephthaloyl chloride is obtained under a high vacuum condition under a kettle liquid temperature of 150 to 170 DEG C. With the method provided by the present invention, the recovery rate of the product reaches 90 to 95%, the product content reaches 99.95% or above after one distilling process, such that energy consumption is reduced. The inner core crystal of the product turns from light red or light yellow to yellowish white or pure white, such that the requirement of aramid fiber 1414 polymerization can be satisfied.

Description

technical field [0001] The invention belongs to the field of preparation of terephthaloyl dichloride, in particular to a preparation method of terephthaloyl dichloride. Background technique [0002] Aramid 1414 is widely used in the military, and DuPont of the United States has imposed a technical blockade on my country for a long time, which restricts the application and development of my country in related fields. Aramid 1414 has extremely high strength, greater than 28 grams per denier, 5 to 6 times that of high-quality steel, 2 to 3 times the modulus of steel or glass fiber, 2 times the toughness of steel, and only the weight of steel 1 / 5. Aramid 1414 involves a wide range of fields and has high requirements for its raw materials, and terephthaloyl chloride is one of its important raw materials, so the quality of terephthaloyl chloride directly affects the performance of the polymerized aramid 1414. quality. At present, there are many methods for preparing terephthalo...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the embodiments of the present invention is to provide a preparation method of terephthaloyl chloride, aiming to solve the problem that there are many methods for preparing terephthaloyl chloride, and all of them have low yield, low purity, and impure center color after crystallization Such defects increase the difficulty of polymerization of aramid fiber 1414, thereby increasing the amount of production waste and affecting the quality of aramid fiber 1414

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