关键词: 重溶剂, 甲苯二异氰酸酯, 间苯二甲酸

Abstract: Polyurethane is a kind of important synthetic material, one of whose components is toluene diisocyanate(TDI). In the production of TDI using heavy solvent, thousands of tons of tar residue was obtained as by-products. It is necessary to recycle the residue with great economic value and ecological value. Residue composition was analysed with Fourier transform infrared spectrometer (FTIR) and thermogravimetric analyzer (TGA). Experiments were designed according to tar residue composition. By hydrolysis of diethyl isophthalate (DEIP) in the residue, high purity isophthalic acid (IPA) was obtained as product. Multiple factors affectingp the yield of isophthalic acid were investigated, such as reaction temperature, reaction time, sodium hydroxide ratio, raw material particle size, and conditions that prevented the formation of impurity. Hydrolysis reaction kinetic parameters of DEIP in the tar residue were calculated by fitting experimental data:reaction order was 3, activation energy was 69.086kJ/mol. Reaction conditions for industrial production were summarized:tar residue was ground to 150μm, NaOH:residue=0.3:1(mass ratio), reaction for 3 hours at 90℃ in water.

Key words: heavy solvent, toluene diisocyanate, isophthalic acid