Toluene-2,4-bisurea (TBU) is an important intermediate for urea route to dimethyl toluene-2,4-dicarbamate and the study on TBU synthesis via the reaction of 2,4-toluene diamine (TDA) and urea is of great significance....Toluene-2,4-bisurea (TBU) is an important intermediate for urea route to dimethyl toluene-2,4-dicarbamate and the study on TBU synthesis via the reaction of 2,4-toluene diamine (TDA) and urea is of great significance. Firstly, thermodynamic analysis shows that the reaction is exothermic and a high equilibrium conversion of TDA is expected due to its large reaction equilibrium constant. Secondly, under the suitable reaction conditions, 130 °C, 7 h, and molar ratio of TDA/zinc acetate/urea/sulfolane 1/0.05/3.5/10, TDA conversion is 54.3%, and TBU yield and selectivity are 39.8% and 73.3% respectively. Lastly, the synthesis of TBU is a 1st order reaction with respect to TDA and the reaction kinetics model is established. This work will provide useful information for commercializing the urea route to toluene-2,4-dicarbamate (TDC).展开更多
A selective reaction of cyclohexanone oxime-blocked tolylene-2,4-diisocyanate（2,4-TDI）with amino siloxane was observed,in which amines were capable of discriminating two reactive groups in the 2,4-TDI molecule.Thus,...A selective reaction of cyclohexanone oxime-blocked tolylene-2,4-diisocyanate（2,4-TDI）with amino siloxane was observed,in which amines were capable of discriminating two reactive groups in the 2,4-TDI molecule.Thus,tolylene-2-tert-butyldimethylsilyloxyethyl carbamide-4-cyclohexanone oxime carbamate was synthesized and its precise structure was determined by single-crystal X-ray diffraction.Moreover,it was found that oxime-blocked isocyanate could react selectively with the–NH2group with the–OH group unprotected in ethanolamine.展开更多
基金Supported by the National Natural Science Foundation of China （20976035, 21076059） the Natural Science Foundation of Hebei Province （B2010000019）
文摘Toluene-2,4-bisurea (TBU) is an important intermediate for urea route to dimethyl toluene-2,4-dicarbamate and the study on TBU synthesis via the reaction of 2,4-toluene diamine (TDA) and urea is of great significance. Firstly, thermodynamic analysis shows that the reaction is exothermic and a high equilibrium conversion of TDA is expected due to its large reaction equilibrium constant. Secondly, under the suitable reaction conditions, 130 °C, 7 h, and molar ratio of TDA/zinc acetate/urea/sulfolane 1/0.05/3.5/10, TDA conversion is 54.3%, and TBU yield and selectivity are 39.8% and 73.3% respectively. Lastly, the synthesis of TBU is a 1st order reaction with respect to TDA and the reaction kinetics model is established. This work will provide useful information for commercializing the urea route to toluene-2,4-dicarbamate (TDC).
基金financially supported by the National Natural Science Foundation of China (Nos. 21176147, 21276149 and 21204044)Program for Scientifc Research Innovation Team in Colleges and Universities of Shandong Province
文摘A selective reaction of cyclohexanone oxime-blocked tolylene-2,4-diisocyanate（2,4-TDI）with amino siloxane was observed,in which amines were capable of discriminating two reactive groups in the 2,4-TDI molecule.Thus,tolylene-2-tert-butyldimethylsilyloxyethyl carbamide-4-cyclohexanone oxime carbamate was synthesized and its precise structure was determined by single-crystal X-ray diffraction.Moreover,it was found that oxime-blocked isocyanate could react selectively with the–NH2group with the–OH group unprotected in ethanolamine.
