非光气途径合成多异氰酸酯的研究进展

Recent Progress on the Non-phosgene Synthesis of Polyisocyanates

多异氰酸酯为聚氨酯弹性体、固体推进剂、胶黏剂、涂料、医药化工中间体等军民两用产品提供重要原料,支撑着现代工业文明的长足进步,改善着人类健康福祉。然而,多异氰酸酯的传统合成方法主要是通过多氨基化合物与光气反应转化而来,剧毒性光气的大量使用给环境造成了危害。为了从源头上实现绿色低碳的生产方式,促进人与自然和谐共生,迫切需要从本质上创新合成路径,发展多异氰酸酯的绿色制备技术。近年来,通过非光气途径合成异氰酸酯,或者通过非异氰酸酯途径制备高性能聚合物材料,已经成为研究的前沿方向之一。本文从氨基甲酸酯热分解脱醇反应、酰胺化合物的Hofmann重排反应、叠氮酰基化合物的Curtius重排反应、羟肟酸的Lossen重排反应、氰酸盐的N-取代反应以及硝基化合物的还原羰基化反应等途径概括了非光气法合成多异氰酸酯的最新进展情况。随着科学技术的不断进步和循环经济对可持续发展的要求不断提高,非光气途径制备多异氰酸酯及其聚氨酯将成为未来发展的潮流和趋势。

Polyisocyanates are important raw materials for military and civilian products such as solid propellants,adhesives,and coatings,supporting the rapid progress of modern industrial civilization.They are also important intermediates for drug synthesis,improving human health and well-being.However,the traditional syntheses of polyisocyanate are mainly through the reactions of polyamines with phosgene,which is highly toxic and harmful to the environment.In order to improve the green and low-carbon production from the source,promote harmonious coexistence between humans and nature,it is urgently necessary to innovate the synthesis path and develop green preparation technology for polyisocyanate.In recent years,the synthesis of isocyanates through non-phosgene methods has become a research frontier as an active intermediate for the synthesis of high-value-added derivatives.The latest progress in the nonphosgene synthesis of polyisocyanate is summarized through pathways such as dealchoholysis of carbonates through pyrolysis,Hofmann rearrangement of amides,Curtius rearrangement on acyl azides,Lossen rearrangement of hydroxamic acid,reductive carbonylation reaction on nitro compounds,N-substitution of cyanates,and so on.With the increasing requirements of circular economy for sustainable development,the syntheses of polyisocyanates and their corresponding polyurethanes through non-phosgene pathways will attract more attention in the future.