The low-pressure hydroformylation of 1-hexene was catalyzed with active carbon-supported noble metal catalysts, such as Rh/AC, MAC, Ru/AC and Pt/AC. In this study, the Rh/AC catalyst exhibited the best property for hydroformylation of 1-hexene with high 1-hexene conversion and high oxygenates' yield, and Rh loading significantly influenced the catalytic activity of hydroformylation of I-hexene. The active carbon-supported cobalt catalyst was studied for comparison. Acting as support for noble metals, the active carbon was more advantageous to hydroformylation of 1-hexene than silica, due to the high BET surface area, contributing to high dispersion of the supported metal, and to the beneficial characteristics in carbonylation, contributing to CO insertion. The hydroformylation reaction on supported Rh catalysts was carried out at different reaction conditions, such as in different temperature from 353 to 433 K and in different initial pressure from 1.0 to 5.0 MPa, to find the most favorable reaction conditions. Solvent effects for hydroformylation of 1-hexene, as well as reaction mechanism on active carbon-supported noble metal catalysts were also studied. Nonpolar and non-protonic solvents showed promotional effects. (C) 2004 Elsevier B.V. All rights reserved.