PURPOSE: To produce isophorone diisocyanate while preventing formation of aggregate, accordingly without causing a trouble related to operation by conducting phosgenation of isophorone diamine hydrochloride derived from isophorone diamine at a high temperature while controlling the weight concentration ratio of the compopents.
CONSTITUTION: This method for continuously producing (E) isophorone diisocyanate (IPDI) is carried out by using a continuous multi-stage reactor composed of (i) a hydrochloride production tank and (ii) two or more phosgene tanks continued therefrom and connected in series, feeding (A) isophorone diamine (IPDA), (B) hydrogen chloride and (C) an inert solvent to the reaction tank (i) to form (D) an isophorone diamine hydrochloride slurry and feeding the resultant slurry and phosgene to the reaction tank (ii). In this production method, the weight concentration ratio of IPDA to its monoisocyanate compound in the reaction mixture in the reaction tank (ii) is kept to 3 to 100 times on IPDI base. The reactions are conducted while keeping the temperature of the reaction tank (i) and the temperature of the reaction tank (ii) respectively to 80 to 120°C and 100 to 170°C.
KATOGI MAMORU
MATSUMOTO MASASHI