Preparation method and preparation device of p-trifluoromethoxy phenyl isocyanate

Abstract

The invention discloses a preparation method and a preparation device of p-trifluoromethoxy phenyl isocyanate. The preparation method comprises the following steps: preparing p-trifluoromethoxy aniline and a solvent into a solution for later use; adding triphosgene and a solvent into the reaction kettle; adding a p-trifluoromethoxyaniline solution dropwise at the temperature of 80-130 DEG C for 0.5-2 hours, and carrying out reflux heat preservation for 0.5-2 hours; the reaction process is monitored by a DCS (Distributed Control System); a reaction mixed solution is obtained; and a continuous distillation mode is adopted for purification, the product yield reaches 96%, and the product content is greater than or equal to 99.5%. The preparation device comprises a mixing kettle, a reaction kettle, a distillation tower, a first condenser, a second condenser, a vacuum unit and a product storage tank, outlets of components with different boiling points are respectively formed in the top, the middle and the bottom of the distillation tower. According to the invention, p-trifluoromethoxy phenyl isocyanate is prepared by adopting a green process, and metering, conveying and operating parameters of materials are all controlled by adopting a DCS (Distributed Control System); one-step synthesis is adopted, the reaction is stable, and side reactions are few; and continuous distillation purification is adopted, so that the product quality and yield are high.

Description

technical field [0001] The invention relates to a preparation method and a preparation device of p-trifluoromethoxyphenyl isocyanate, belonging to the field of chemical equipment. Background technique [0002] p-Trifluoromethoxy isocyanate is an important intermediate of medicine, pesticide and polymer materials, and is widely used in the synthesis of medicine and pesticide compounds. The synthesis of p-trifluoromethoxy isocyanate can be prepared by one-step reaction with p-trifluoromethoxyaniline and solid phosgene in an inert solvent medium, as disclosed in Chinese patent CN107540573A. Isocyanate production process, add the measured organic solvent m-xylene into the reaction kettle, add solid phosgene through the feeding hole, control the temperature at about 80°C and drop p-aminotrifluoromethoxybenzene, control the dropping speed and reaction time 4h; the molar ratio of p-aminotrifluoromethoxybenzene to phosgene is 1:1.019; the hydrogen chloride gas generated during the ...

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Problems solved by technology

However, catalysts such as triethylamine, pyridine, N-methylpyrrole or tetrabutylurea are used in the reaction process, which increases the difficulty of post-treatment.

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