On the Thermal Dissociation of Organic Compounds. VIII. The Effects of the Substituents on the Thermal Dissociation of Tri-substituted Ureas
作者:Teruaki Mukaiyama、Shoichiro Ozaki、Yasuhiro Kobayashi
DOI:10.1246/bcsj.29.51
日期:1956.1
The rate constants of the thermal dissociation of tri-substituted ureas in fatty acids and alcohols were determined. It was shown that tri-substituted ureas dissociate faster than 1, 3-dis-substituted ureas. In tri-substituted ureas, the rates in alcohols are faster than in fatty acids in contrast with 1, 3-disubstituted ureas.Tetra-substituted ureas which are not formed by the addition reaction do not react under the same condition with tri-substituted ureas.The bimolecular mechanism for the dissociation of ureas involving the direct attack of one solvent molecule on urea was denied.
三取代脲在脂肪酸和醇中的热解离速率常数已被测定。结果显示,三取代脲的解离速度快于1,3-二取代脲。在三取代脲中,醇中的解离速率快于脂肪酸,而1,3-二取代脲则恰恰相反。不是通过加成反应形成的四取代脲在与三取代脲的相同条件下不发生反应。否定了涉及一个溶剂分子直接攻击脲的脲解离的双分子机制。