Catalytic Hydrogenation of Substituted Quinolines on Co–Graphene Composites

A set of 20 composites was prepared by pyrolysis of Co2+ complexes with 1,10‐phenanthroline, melamine and 1,2‐diaminobenzene. These composites were tested as the catalysts for the hydrogenation of quinolines. As shown by powder X‐ray diffraction and TEM, the composited contained Co particles of several dozen nm sizes. The composition (elements content), Raman spectra X‐ray photoelectron spectra parameters of the composites were analyzed. It was found that there was no distinct factor that controlled the yield of 1,2,3,4‐tetrahydroquinolines in the investigated process. The yields of the respective products were in the range 90–100 %. The three most active composites were selected for scale‐up and hydrogenation of a series of substituted quinolines. Up to 97 % yield of 1,2,3,4‐tetrahydroquinoline was obtained on a 50 g scale. Five representative substituted quinolines were synthesized on a 10–20 grams scale using the Co‐containing composites as the catalysts. Composites containing Co nanoparticles and graphene‐like carbonaceous particles on a SiO2 support were prepared and tested as the catalysts for the hydrogenation of quinoline by H2. 1,2,3,4‐Tetrahydroquinoline was synthesized on a 50 g scale, and five substituted quinolines were prepared on a 10–20 gram scale. The composites are good alternative to platinum group metal catalysts for hydrogenation processes.