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采用密度泛函理论B3LYP/6-31+G(d,p)方法研究了甲苯-2,4-二异氰酸酯(2,4-TDI)与仲胺类化合物反应过程中的质子转移效应.研究发现甲醇分子对反应有显著的催化效应,可使反应能垒大幅降低,这表明含活泼氢的化合物会加速质子转移过程,从而加快反应速率.2,4-TDI与甲基-N-甲基氨基甲酸酯的催化加成反应为一步反应,其反应过渡态呈六元环结构;而2,4-TDI与N-甲基对硝基苯胺、二苯胺、1,2-二氢-2,2,4-三甲基喹啉等芳香胺类化合物的催化加成反应经历了两步反应,其中第一步为速率控制步骤.研究表明,在与2,4-TDI的反应中,芳胺化合物的活性高于甲基-N-甲基氨基甲酸酯的活性,计算的反应活性顺序与实验结果一致.
The proton transfer effect of toluene-2,4-diisocyanate (2,4-TDI) with secondary amines was studied by density functional theory B3LYP / 6-31 + G (d, p) Methanol molecules have a significant catalytic effect on the reaction, the reaction energy barrier can be significantly reduced, indicating that active hydrogen-containing compounds will accelerate the proton transfer process, thereby speeding up the reaction rate .2,4-TDI and methyl-N- methylamino Formate catalyzed addition reaction is a one-step reaction, the reaction transition state showed a six-membered ring structure; and 2,4-TDI and N-methyl p-nitroaniline, diphenylamine, 1,2-dihydro- 2,4-trimethylquinoline and other aromatic amine compounds catalyzed the addition reaction has gone through two steps, of which the first step is the rate control step.The results show that in the reaction with 2,4-TDI, aromatic amine The activity of the compound is higher than that of methyl-N-methylcarbamate. The calculated reaction sequence is consistent with the experimental results.