PROCESS FOR PRODUCING AND RECOVERING TOLUENE DIAMINE FROM TOLUENE DIISOCYANATE DISTILLATION RESIDUES

摘要

PURPOSE: A method for recovering and preparing toluene diamine by decomposing high boiling point waste tar obtained as a side-product in a chemical process for manufacturing toluene diisocyanate under reaction conditions of near critical temperature and pressure of water using ammonia aqueous solution as a reaction medium is provided, which reduces waste treatment costs and shortage of a filled-up land. CONSTITUTION: In a process of recovering and preparing toluene diamine by decomposing high boiling point waste tar obtained as a side-product in a chemical process for the manufacture of toluene diisocyanate (TDI) by phosgenation of toluenediamine, the decomposition is carried out under conditions of 350 to 600 deg.C and 170 to 500 atm. using ammonia aqueous solution as a reaction medium. The process reduces the treatment costs of tars remarkably and reutilizes toluene as a decomposition side product to a process for synthesizing the TDI.