重溶剂法TDI焦油残渣的分析与利用

聚氨酯是一种重要的合成材料, 其成分之一是甲苯二异氰酸酯(TDI)。在重溶剂法生产TDI的过程中, 每年会产生数千吨的副产物焦油残渣, 该残渣的回收利用十分必要, 具有较大的经济价值和生态价值。通过傅里叶变换显微红外光谱仪(FTIR)和磁悬浮热重分析仪(TGA)分析残渣的成分, 设计合理的实验, 水解残渣中的间苯二甲酸二乙酯(DEIP)得到高纯度的间苯二甲酸(IPA)产品。分别考察了影响IPA收率的多个因素:反应温度、反应时间、碱配比、原料颗粒大小等, 以及避免生成杂质的反应条件。拟合计算了焦油中DEIP的水解反应动力学参数:反应级数为3, 活化能为69.086kJ/mol。总结了工业生产的反应条件是:焦油残渣粉碎至平均粒径150μm, NaOH与残渣的质量比为0.3, 在90℃的水中反应3h。

Analysis and recycle of tar residue from TDI production using heavy solvent

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.