Continuous flow reductive amination of cyclohexanone using Pd/C catalyst with high productivity

Amines represent crucial intermediates in fine chemical synthesis, finding extensive applications across pesticide, dye, and pharmaceutical industries. N,N-Dimethyl tertiary amines can be efficiently synthesized through reductive amination of dimethylamine. We developed an environmentally benign continuous flow reductive amination system employing a micro-packed bed reactor (μ-PBR) with a Pd/C catalyst prepared via direct impregnation. This system successfully produces N,N-dimethylcyclohexylamine (DMCHA) in an aqueous system, achieving high selectivity (99.5%), impressive space–time yields (2.7 × 104 g L−1 h−1), and operates without requiring additional additives. In addition, the reaction system demonstrated excellent stability during a 120-hour continuous test and proved suitable for both aromatic aldehydes and aromatic amines.