Selective Synthesis of Hydrocinnamaldehyde over Bimetallic Ni–Cu Nanocatalyst Supported on Graphene Oxide

Hydrogenation of cinnamaldehyde yields hydrocinnamaldehyde, cinnamyl alcohol, and hydrocinnamyl alcohol, all having important applications in different industries. The selective synthesis of hydrocinnamaldehyde, which is a perfumery compound, from cinnamaldehyde is challenging. In the current work, bimetallic nanocatalyst Ni–Cu supported on reduced graphene oxide (RGO) was prepared via the solvothermal method. Different combinations of Ni–Cu@RGO were used for the hydrogenation of cinnamaldehyde in methanol as a solvent at 20 bar and 150 °C. Ni–Cu ratio was altered to understand its influence on the selectivity of the desired product hydrocinnamaldehyde. Hydrogenation of C═C bond over the C═O bond was favored over 5% Ni–Cu@RGO catalyst in the optimized ratio of Ni:Cu (1:1). Optimization of process parameters and characterization of fresh and reused catalyst was performed. The Langmuir–Hinshelwood–Hougen–Watson model was used to fit the reaction data. The catalyst is robust and reusable, and the process is green.