Catalytic Continuous Reductive Amination with Hydrogen in Flow Reactors

Reductive amination with hydrogen is a green and atom-efficient method to construct amines from accessible aldehydes and ketones. Flow reactors, with superior mass and heat transfer rate because of higher specific surface area, have emerged as a powerful tool to conduct reductive amination with high efficiency and selectivity. This article discusses the influence of catalysts, solvents, temperatures, additives, and substrate properties on reductive amination. Following this, a summary of research on reductive amination with hydrogen in flow reactors is provided. The investigations were classified based on distinct nitrogen sources, encompassing the use of ammonia, amines, and nitro compounds. Based on the influencing factors and reaction cases, the article analyzes the enhancement effects of temperature control, mass transfer intensification, and residence time distribution in flow reactors on the reductive amination. Finally, the article gives a conclusion by addressing challenges and prospects for further developments in this field. Continuous flow technology has been applied to various reductive amination processes. The advantages of flow reactors, including temperature control, mass transfer intensification, and residence time distribution, have significantly improved the reaction performance. Furthermore, this technology provided a platform for scientific research, such as kinetic studies. This article summarized the application of continuous flow technology in reductive amination. image