ABSTRACT

This review summarizes the recent studies on the synthesis of secondary amines by one-pot amination of aldehydes and ketones over heterogeneous catalysts. Amines are widely applied as the key intermediates in chemical industry for the synthesis of various commodities such as agrochemicals, drugs, detergents, lubricants, food-additives and polymers. Direct catalytic reductive amination of carbonyl compounds was considered which generally includes two steps: (i) formation of imines by interactions of aldehydes or ketones with amines, and (ii) subsequent hydrogenation of imines. Synthesis of secondary amines from carbonyl compounds and amines generated in situ under reaction conditions from their progenitors, e.g., respectively, alcohols or nitro-compounds, is also discussed in detail. Recent progress in application of hydrogen sources alternative to gaseous H₂, such as formic acid, NaBH₄, CO and water, favored development of metal-free catalysts including solid acid catalysts. The review addresses the scope of the amination reaction with aldehydes/ketones and nitro/amine compounds of different structure, the effect of the solvent, reaction conditions and catalyst properties. In addition, catalyst regeneration and reuse, kinetic regularities and kinetic modeling with an emphasis on the continuous mode of one-pot amination have been systematically summarized and discussed. It is suggested that the future work should focus on revealing the role of the catalytically active sites addressing their acid–base properties and the correlation between catalyst properties and the reaction performance, elucidating kinetic parameters and designing feasible reactor system for further industrial implementation.

摘要

本文综述了近年来在多相催化剂上通过醛和酮的一锅法胺化合成仲胺的研究。胺作为化学工业中的关键中间体被广泛应用于合成各种商品，如农用化学品、药物、洗涤剂、润滑剂、食品添加剂和聚合物。羰基化合物的直接催化还原胺化被认为通常包括两个步骤：（i）通过醛或酮与胺的相互作用形成亚胺，和（ii）) 亚胺的后续氢化。还详细讨论了从羰基化合物合成仲胺和在反应条件下从其前体（例如，醇或硝基化合物）原位生成的胺。甲酸、NaBH _{4等替代气态H 2}的氢源应用研究进展，CO 和水，有利于开发无金属催化剂，包括固体酸催化剂。综述涉及不同结构的醛/酮和硝基/胺化合物的胺化反应范围、溶剂的影响、反应条件和催化剂性能。此外，系统地总结和讨论了催化剂再生和再利用、动力学规律和动力学模型，重点是一锅胺化的连续模式。建议未来的工作重点是揭示催化活性位点在解决其酸碱性质方面的作用以及催化剂性质与反应性能之间的相关性，阐明动力学参数并设计可行的反应器系统以进一步工业实施。