过渡金属氧化物催化腈水合生成酰胺的研究进展

腈水合生成酰胺具有原子经济性高以及无其他副产物生成的优点。通常腈水合生成酰胺是在强酸或强碱催化下进行的,但其具有腈过度水解生成羧酸以及需要中和催化剂生成盐等缺点。采用过渡金属氧化物如氧化锰(MnO₂)、氧化镍(NiO)、氧化铈(CeO₂)以及氢氧化钌[Ru(OH)_x]为催化剂替代强酸或强碱可克服上述缺点。本文总结了上述过渡金属氧化物为催化剂催化腈水合生成酰胺反应的进展,从中可以看到腈水合生成酰胺反应依赖于催化剂的种类、制备方法以及腈的结构。对每种催化剂的制备方法、使用范围、优缺点进行了分析。对各种催化剂催化腈水合生成酰胺反应的可能机理进行讨论。根据以上讨论,预期此类催化剂将向复合型和负载型方向发展。

Progress on hydration of nitriles to amides catalyzed by transition metal oxides

Hydration of nitriles to the corresponding amides has the advantages of high atomic economy and avoiding formation of undesirable side products. Traditionally, the hydration of nitriles was achieved by the catalysis of strong acid or alkali. However, it has the drawbacks of over hydrolysis of amides into carboxylic acids and the formation of salts from the neutralization of the catalysts. To overcome these difficulties various transition metal oxides including manganese dioxide (MnO₂), nickel oxide (NiO), ceria (CeO₂) and ruthenium hydroxide [Ru (OH)_x] to replace strong acid or alkali have been used as catalysts in this reaction. In this article, the hydration of various nitriles to the corresponding amides catalyzed by the above transition metal oxides has been summarized. It can be seen that the hydration of nitriles to the amides depends on the type and preparation method of catalysts and the structure of nitriles. The preparation method, application scope, advantages and disadvantages of each catalyst are also illustrated. In addition the possible catalytic mechanisms of the catalysts are discussed. It is expected that the catalysts with excellent performance will be from complex transition metal oxides and supported metal oxides based on the above discussions.