Guo Zhuhua, Ding Xiaoshu, Wang Yanji
School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300401, PR China.
ACS Omega. 2024 Feb 28;9(10):11168-11180. doi: 10.1021/acsomega.3c10069. eCollection 2024 Mar 12.
Isocyanate, a pivotal chemical intermediate to synthesize polyurethane with widespread applications in household appliances, automobiles, and construction, is predominantly produced via the phosgene process, which currently holds a paramount status in industrial isocyanate production. Nonetheless, concerns arise from the toxicity of phosgene and the corrosiveness of hydrogen chloride, posing safety hazards. The synthesis of isocyanate using nonphosgene methods represents a promising avenue for future development. This article primarily focuses on the nonphosgene approach, which involves the formation of carbamate through the reaction of nitro-amino compounds with carbon monoxide, dimethyl carbonate, and urea, among other reagents, subsequently leading to the thermal decomposition of carbamate to get isocyanate. This paper emphasizes the progress in catalyst development during the carbamate decomposition process. Single-component metal catalysts, particularly zinc, exhibit advantages such as high activity, cost-effectiveness, and compatibility with a wide range of substrates. Composite catalysts enhance isocyanate yield by introducing a second component to adjust the active metal composition. The central research direction aims to optimize catalyst adaptation to reaction conditions, including temperature, pressure, time, and solvent, to achieve high raw material conversion and product yield.
异氰酸酯是合成聚氨酯的关键化学中间体，在家用电器、汽车和建筑等领域有着广泛应用，主要通过光气法生产，目前在工业异氰酸酯生产中占据首要地位。然而，光气的毒性和氯化氢的腐蚀性引发了担忧，构成安全隐患。采用非光气法合成异氰酸酯是未来发展的一条有前景的途径。本文主要聚焦于非光气法，该方法涉及通过硝基 - 氨基化合物与一氧化碳、碳酸二甲酯和尿素等试剂反应形成氨基甲酸酯，随后氨基甲酸酯热分解得到异氰酸酯。本文强调了氨基甲酸酯分解过程中催化剂开发的进展。单组分金属催化剂，特别是锌，具有高活性、成本效益高以及与多种底物兼容性好等优点。复合催化剂通过引入第二种组分来调整活性金属组成，从而提高异氰酸酯产率。核心研究方向旨在优化催化剂对反应条件（包括温度、压力、时间和溶剂）的适应性，以实现高原料转化率和产品产率。
