Monoterpenoid Oximes Hydrogenation Over Platinum Catalysts

Platinum nanoparticles supported on MgO, Al 2 O 3 , ZrO 2 , TiO 2 were utilized for monoterpenoid oximes hydrogenation. Monocyclic menthone and carvone oximes synthesized from bio-derived monoterpenoids with a different structure were used to explore the effect of substrate structure on the reaction regularities. The oximes hydrogenation was carried out under hydrogen atmosphere at 100 °C using methanol as a solvent. Platinum catalysts were prepared by the impregnation methods. The catalysts were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray fluorescence spectroscopy, nitrogen physisorption. Hydrogenation of carvone oxime containing a conjugated oxime group and several reducible functional groups resulted in both hydrogenation and deoximation giving 5-isopropyl-2-methylcyclohexanamine and carvomenthone over Pt/Al 2 O 3 and Pt/ZrO 2 catalysts. Menthone oxime hydrogenation over Pt/Al 2 O 3 catalysts with an average particle size of 0.8 nm provided the desired menthylamine formation with the selectivity of 90% at complete oxime conversion. Platinum catalysts based on MgO, ZrO 2 and TiO 2 enhanced menthone oxime deoximation to menthone.