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用自洽场分子轨道法(半经验AM1法及从头算HF/3-21G 法)研究了基态丙烯酸脱羧的反应途径.计算结果表明,除前人从理论上已经得到的一步反应途径外,尚有一个与之竟争的二步反应途径,且两步反应的总速率大于一步反应的.计算所得的反应速率常数很小,与实验结果(丙烯酸在827K 仅有25%左右发生脱羧,脱水等反应)是一致的.研究表明,有较稳定的中间体存在,有可能在实验中被检测到,但有待于进一步验证.
The reaction pathway of ground-state acrylic acid decarboxylation was studied by using the self-consistent field orbit method (semi-empirical AM1 method and ab initio HF / 3-21G method). The calculated results show that, in addition to the one- There is a competing two-step reaction route, and the total reaction rate of the two-step reaction is larger than that of the one-step reaction, and the calculated reaction rate constant is very small. Compared with the experimental result (decarboxylation, dehydration and the like of only about 25% of acrylic acid at 827K) Reaction) is consistent.Research shows that there are more stable intermediates exist, it may be detected in the experiment, but to be further verified.