| 摘要 |
PURPOSE:To obtain the titled compound containing a large amount of a two nucleus compound of MDI (diphenylmethane diisocyanate) advantageously, by using aniline, CO and a methylenating agent as raw materials, carrying out urethanization with a specific solvent, two-stage methylenation under specific conditions, thermal decomposition and separation, and purification process. CONSTITUTION:Aniline is reacted with CO and an alcohol in the presence of an oxidizing agent using a catalytic system consisting of a platinum group metal or a compound containing the platinum group metal, a halogen-containing compound and an optionally added basic substance as a urethanization catalyst, and N-phenylurethane is separated and collected from the reaction mixture. The urethane is reacted with a methylenating agent using 30-60wt% aqueous solution of inorganic acid as a catalyst at 40-150 deg.C, the aqueous phase containing the inorganic acid is separated from the reaction mixture, the prepared organic phase is heat-treated in the presence of N-phenylurethane and a carbonic acid or solid acid having <=4pKa value at 40-200 deg.C to give a condensate. It is thermally decomposed in a solvent having 150-350 deg.C boiling point, and the solvent is recovered from the thermal decomposition product to give the desired compound.
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