Study On Green Synthesis Of1,6-Hexamethylene Diisocyanate

1,6-Hexamethylene diisocyanate (HDI) is one of the most important materials in polyurethane industry, which has a broad market prospect. This paper reviews methods for synthesis of HDI. After comparing these methods, it is found that the process of thermal decomposition of hexamethylene diurethane (HDU) to produce HDI is the most perspective method at present, which is described in detail. Based on the former study on this subject, the batch reactor has been improved, the synthesis mechanism of HDU and HDI have been observed and studied. The process conditions of BJG-1, BJG-2, BJG-3and BJG-4have been optimized, in terms of reaction temperature、reaction time、HDU and catalyst concentrations. It is found that the BJG-1has good catalytic activity, the yield of HDI reach77.74%, the reaction conditions as follow:reaction temperature280℃, reaction time20min, HDU concerntration5%, BJG-1concerntration0.375%.