Study On Synthesis Of 1,6-Hexamethylene Diisocyanate By Thermal Decomposition

1,6-Hexamethylene diisocyanate (HDI) is one of the most important materials in polyurethane industry..This paper reviews methods for synthesis of HDI. After comparing these methods, it is decided to choose the process of thermal decomposition of Hexamethylene diurethane (HDU) for producing HDI. which is described in detail. Based on the former study on this subject, the batch reactor has been improved, the analytical method and catalytic mechanism have been observed and studied. Through the experiments, it is found that the single solution can have a better performance than the combination solutions in the batch reactor. The process conditions of activated Al2O3, nanomerter Fe, micrometer Zn, nanomerter ZnO, Zinc picolinate, Zinc caprylate, Zinc stearate, the combination of micrometer Zn and activated Al2O3, and the combination of micrometer Zn, activated Al2O3 and nanomerter ZnO have been optimized, in terms of reaction temperature,reaction time,HDU and catalyst concentrations. It is found that the metallic oxide catalysts are able to reduce the reaction time and decrease the reaction temperature. The flow reactor has been designed. And it is pointed out the standard of how to choose the solution and catalyst in the flow reactor.