清洁合成1,6-六亚甲基二异氰酸酯

Clean Synthesis of 1,6-Hexamethylene Diisocyanate

利用1,6-六亚甲基二氨基甲酸正丁酯(HDU-B)热分解反应清洁合成了1,6-六亚甲基二异氰酸酯(HDI)。通过对HDU-B热分解反应机理的分析和反复实验,自行设计了热分解反应装置,并利用此装置考察了在一定的压力下,反应温度、作为热载体的惰性高沸点溶剂、催化剂等对HDU-B热分解反应的影响。实验结果表明,最佳惰性高沸点溶剂为环烷油,适宜的催化剂有锌、铝和氧化锌及它们之间组合的双组分催化剂。实验还发现,具有弱酸性的Lewis酸金属氧化物和锌对HDU-B热分解反应具有一定的正协同作用。最佳反应条件为:采用锌和氧化锌双组分催化剂,反应温度250℃,真空度0.094MPa,反应时间15min。在此条件下,HDI的收率为81.24%。

1,6-Hexamethylene diisocyanate （HDI）, an important chemical intermediate for polyurethane, was cleanly synthesized by thermal decomposition of 1,6-hexamethylene di-n-butylurethane （HDU-B） in inert high-boiling point solvent. In view of proposed mechanism of thermal decomposition and trial-and-error experiments, the apparatus used in decomposition was designed and assembled. Under specific pressure, effects of temperatures, inert high-boiling point solvents and catalyst types on decomposition were investigated. Under optimal conditions ：naphthenic oil as inert high-boiling point solvent, zinc-zinc oxide as dual-component catalyst ,temperature 250 ℃, pressure 0.094 MPa and time 15 min,yield of HDI can reach 81.24%. Besides,zinc and metal oxides with weak Lewis acidity show positive synergistic effect for the thermal decomposition.