Abstract: The recovery of toluene diamine from tar waste residues discharged from the synthesis process of toluene diisocyanate comprising steps of: a) grinding the tar waste residues into particles; b) dispersing the particles of tar waste residues into a phase transfer catalyst, alkali and water to obtain a slurry, said phase transfer catalyst being selected from the group consisting of higher alcohols, polyols, polyether compounds and combinations thereof having a boiling point ranging from 120 to 280° C.; c) under the protection of a protective gas, subjecting the slurry to a hydrolysis reaction at a temperature of 120-180° C. under a meter-measured pressure of 0-0.95 MPa to produce toluene diamine; and d) recovering toluene diamine from the hydrolysis reaction solution. The present invention achieves highly efficient recovery of toluene diamine (the recovery rate of TDA is up to 60%) under mild conditions such as 120-180° C. and 0-0.

Abstract: The recovery of toluene diamine from tar waste residues discharged from the synthesis process of toluene diisocyanate comprising steps of: a) grinding the tar waste residues into particles; b) dispersing the particles of tar waste residues into a phase transfer catalyst, alkali and water to obtain a slurry, said phase transfer catalyst being selected from the group consisting of higher alcohols, polyols, polyether compounds and combinations thereof having a boiling point ranging from 120 to 280° C.; c) under the protection of a protective gas, subjecting the slurry to a hydrolysis reaction at a temperature of 120-180° C. under a meter-measured pressure of 0-0.95 MPa to produce toluene diamine; and d) recovering toluene diamine from the hydrolysis reaction solution. The present invention achieves highly efficient recovery of toluene diamine (the recovery rate of TDA is up to 60%) under mild conditions such as 120-180° C. and 0-0.