Production method and production device of phenyl isocyanate

Abstract

The invention discloses a production method of phenyl isocyanate. The production method comprises the following steps: preparing aniline and a solvent into an aniline solution for later use; adding triphosgene and a solvent into the reaction kettle; dropwise adding an aniline solution at the temperature of 60-130 DEG C for 0.5-1.5 hours, and carrying out reflux heat preservation for 0.5-1.5 hours; the reaction process is monitored by a DCS (Distributed Control System); a reaction mixed solution is obtained; a continuous distillation mode is adopted for purification, the product phenyl isocyanate is separated from byproducts, the yield reaches 94%, and the product content is larger than or equal to 99.5%. The production device comprises a mixing kettle, a reaction kettle, a distiller, a condenser and a product storage tank, and a low-boiling-point byproduct outlet, a product outlet and a high-boiling-point byproduct outlet are respectively formed in the top, the middle and the bottom of the distiller. The phenyl isocyanate is prepared by adopting a green process, low-toxicity chemical triphosgene and a solvent are adopted, 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 production method and a production device of phenyl isocyanate, belonging to the field of chemical equipment. Background technique [0002] Phenyl isocyanate is an important intermediate of medicine, pesticide and polymer materials, and is widely used in the synthesis of substituted urea compounds. The traditional synthesis methods of phenyl isocyanate include phosgene method, Curtius rearrangement method, haloform β elimination method, one-step carbonyl method, phenylcarbamate thermal decomposition method, etc., among which phosgene method is most commonly used. For example, Zhang Fusheng (Synthetic technology of isocyanate TDI, MDI, etc., Liaoning Chemical Industry, 1996, 2: 14-16) dissolved molten diaminotoluene in chlorobenzene, reacted with phosgene at 35-45 ° C at low temperature, and then heated it at 130 High temperature reaction with phosgene at ℃, after the reaction, use nitrogen to drive out hydrogen chloride to o...

AI Technical Summary

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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