A method of producing toluene diisocyanate (TDI) in the process of the toluene diamine (TDA) phosgenation reaction in the gaseous phase

摘要

The invention relates to the method for producing toluene diisocyanate (TDI) in the process of toluene diamine phosgenation (TDA) in the gaseous phase, which uses toluene diamine (TDA) contaminated with solids as a substrate. According to the invention, a method for producing toluene diisocyanate TDI in the phosgenation process of toluene diamine TDA, in the gaseous phase, characterised by the fact that as one of the substrates, non-distilled toluene diamine TDA is used, which contains up to 4% by weight of non-volatile substances, and the process of toluene diamine (TDA) evaporation is carried out in a thin film evaporator that is equipped with scrapers placed on the rotor, wherein the non-volatile substances in the toluene diamine TDA derived from toluene diamine TDA decomposition in conditions of carrying raw material conversion to the gas phase are carried away into the space located at the bottom of the evaporator 1.