The blocking reaction of polyisocyanates with active hydrogen containing subs tances and the deblocking of the reaction products have been investigated by IR and TGA. The results showed that the initial deblocking tem...The blocking reaction of polyisocyanates with active hydrogen containing subs tances and the deblocking of the reaction products have been investigated by IR and TGA. The results showed that the initial deblocking temperature of the blocked polyisocyanates were mainly determined by active hydrogen substances. The deblocking temperature of toluene diisocyanate blocked with methylethylketoxime was 110 ℃ and this temperature could be more or less reduced by using organic tin catalyst at deblocking reaction.展开更多
The reaction of the CH3 radical with molecular HNCO was examined using MP2 method at the 6311++g**basis set level.The geometry configures of reactants,intermediates,transition states and products were optimi...The reaction of the CH3 radical with molecular HNCO was examined using MP2 method at the 6311++g**basis set level.The geometry configures of reactants,intermediates,transition states and products were optimized.The result shows that the reaction CH3+HNCO→CH4+NCO is an absorbing hydrogen atomprocess,and there is a hydrogenbond complex(M) produced by the interaction of reactants,the energy of which is 813kJ/mol,less than that of the reactants.展开更多
文摘The blocking reaction of polyisocyanates with active hydrogen containing subs tances and the deblocking of the reaction products have been investigated by IR and TGA. The results showed that the initial deblocking temperature of the blocked polyisocyanates were mainly determined by active hydrogen substances. The deblocking temperature of toluene diisocyanate blocked with methylethylketoxime was 110 ℃ and this temperature could be more or less reduced by using organic tin catalyst at deblocking reaction.
文摘The reaction of the CH3 radical with molecular HNCO was examined using MP2 method at the 6311++g**basis set level.The geometry configures of reactants,intermediates,transition states and products were optimized.The result shows that the reaction CH3+HNCO→CH4+NCO is an absorbing hydrogen atomprocess,and there is a hydrogenbond complex(M) produced by the interaction of reactants,the energy of which is 813kJ/mol,less than that of the reactants.
