Silica-supported Cu (Cu/SiO2) prepared by using an organic additive-assisted impregnation method was employed as a catalyst for the dehydrogenation of 3-methyl-2-butanol (3M2BO) to 3-methyl-2-butanone (methyl isopropyl ketone, MIPK). The utilization of organic additives, especially mannitol, during the impregnation protocol has led to the generation of a Cu/SiO2catalyst containing highly dispersed Cu nanoparticles, i.e. high Cu surface area (SACu). These properties contributed to the high activity of the mannitol-assisted Cu/SiO2catalyst, in which the activity was limited only by the equilibrium nature of the reaction. The proportional relationship between the formation rate of the MIPK with the SACuconfirmed the benefits of the utilization of organic additives. In addition, the improvement in the SACuof Cu/SiO2prepared using mannitol only gave a negligible side product originating from the dehydration of 3M2BO; thus, the equilibrium MIPK yield of 99.5% was achieved even at 300 °C.Graphical AbstractA silica-supported Cu (Cu/SiO2) catalyst prepared via impregnation-assisted mannitol gave remarkable catalytic activity for the vapor-phase dehydrogenation of 3-methyl-2-butanol to 3-methyl-2-butanone. The outstanding performance of the Cu/SiO2catalyst derived from the generation of a Cu-catalyst with a high dispersion of Cu nanoparticles, i.e. large Cu surface area. The equilibrium 3-methyl-2-butanone yield of 99.5% was achieved even at 300 °C.