Insights into the Organocatalyzed Synthesis of Urethanes in Supercritical Carbon Dioxide: An In Situ FTIR Spectroscopic Kinetic Study
作者:Christopher A. Smith、Henri Cramail、Thierry Tassaing
DOI:10.1002/cctc.201301002
日期:2014.3.18
The kinetics of urethane (carbamate) formation in supercritical CO2 (scCO2) has been studied by in situ FTIR spectroscopy by using the reaction between n‐butanol and toluene‐2,4‐diisocyanate as a model for the synthesis of polyurethanes. We have evaluated the efficiency of different organocatalysts for this transformation to eliminate the need for potentially toxic organotin compounds. Bicyclic guanidines
通过使用正丁醇与甲苯-2,4-二异氰酸酯之间的反应作为聚氨酯合成的模型,通过原位FTIR光谱研究了超临界CO 2(scCO 2)中氨基甲酸酯(氨基甲酸酯)形成的动力学。我们已经评估了不同有机催化剂进行此转化的效率,从而消除了对潜在有毒有机锡化合物的需求。双环胍和am(7-甲基-1,5,7-三氮杂双环[4.4.0] dec-5-ene和1,8-二氮杂双环[5.4.0] undec-7-ene)显着促进了反应速率,但我们发现它们在scCO 2中的活性与传统介质中的反应相比,由于形成了碳酸胍盐或烷基碳酸alkyl盐,因此降低了H 2 O 3。在scCO 2中,这些催化剂对水的存在也很敏感,并且可能导致脲基甲酸酯或异氰脲酸酯副产物的形成。另一方面,我们证明了用胺N-氧化物(N-甲基吗啉-N-氧化物)催化适合于scCO 2介质。