Continuous reductive amination to synthesize primary amines with high selectivity in flow

•Nickel catalyst for primary amine synthesis with high selectivity (up to 99%) under very mild conditions.•Design of a continuous reductive amination process for primary amine synthesis.•Excellent stability (200 h without activity loss) at high substrate concentration (10 wt.%).•A wide range of substrates (aldehydes, ketones, and furfural).•Establishment of a kinetic model for benzaldehyde reductive amination.