CeO2 as a versatile and reusable catalyst for transesterification of esters with alcohols under solvent-free conditions
作者:Masazumi Tamura、S. M. A. Hakim Siddiki、Ken-ichi Shimizu
DOI:10.1039/c3gc40408k
日期:——
CeO2 acted as an efficient and reusable heterogeneous catalyst for transesterification of esters with alcohols under the solvent-free conditions at 160 °C. Among the 11 kinds of metal oxides, CeO2 is the most suitable catalyst in terms of catalytic activity, leaching-resistance and reusability. This catalytic system tolerates various esters and alcohols, and valuable esters such as heteroaromatic esters and benzyl benzoates are produced, demonstrating a practical utility of the system. On the basis of kinetic analysis and in situ IR studies of adsorbed species, a reaction mechanism is proposed, in which proton abstraction of alcohol by a Lewis base site of CeO2 to yield alkoxide species is the rate-limiting step.
CeO2 是一种高效且可重复使用的异相催化剂,用于在 160 °C 无溶剂条件下进行酯与醇的酯交换反应。在 11 种金属氧化物中,CeO2 是催化活性、耐浸出性和可重复使用性方面最合适的催化剂。该催化体系可耐受多种酯类和醇类,并能生成杂芳香族酯和苯甲酸苄酯等有价值的酯类,证明了该体系的实用性。根据动力学分析和对吸附物种的原位红外研究,提出了一种反应机理,其中 CeO2 的路易斯碱基位点对醇的质子抽取生成烷氧基物种是限速步骤。
CeO2-catalysed one-pot selective synthesis of esters from nitriles and alcohols
were tested for one-pot selective synthesis of esters fromnitriles and alcohols. Ceria (CeO2) showed more than two orders of magnitude higher activity than the other oxides. CeO2 acted as a reusable and effective catalyst for the ester synthesisfrom various nitriles and alcohols under neutral and solvent-free conditions at 160 °C. This method provides a rare example for the synthesis of heteroaromatic