Scalable preparation of stable and reusable silica supported palladium nanoparticles as catalysts for N-alkylation of amines with alcohols

•Pd@SiO2 catalyzed N-alkylation of amines with alcohols is reported.•Pd@SiO2 preparation has been up-scaled to kilogram scale.•Pd-NPs prepared in both 1g and 2 kg exhibited similar structures and activity.•Functionalized and structurally diverse N-alkylated amines were synthesized.•Method is applicable for the preparation of some existing drugs.