The synthesis and characterization of the catalyst precursor HRh(CO)(TPPMS)(3) was carried out by ligand exchange techniques starting from HRh(CO)(PPh3)(3) with an excess of TPPMS ligand [TPPMS] = (C6H5)(2)P(M-C6H4SO3Na), or prepared in situ from RhCl(3 center dot)3H(2)O and TPPMS under high purity syngas. When the hydrosoluble complex was used as a catalyst precursor in the two phase hydrogenation reaction of l-hexene, cyclohexene, styrene and 2,3-dimethyl-l-butene, the main hydrogenated products were obtained with high conversion rates. Under the following reaction conditions T= 343 K, P = 13.6 atm, 600 rpm and S/C = 600/1, the substrates showed the following reactivity order: styrene > l-hexene > cyclohexene > 2,3-dimethyl-1-butene. A quaternary equimolar mixture and one quaternary mixture which simulates the olefin quantities present in real naphtha, showed the same hydrogenation order. The catalyst showed recycling properties without significant loss of activity and sulfur tolerance when benzothiophene is present in the olefin mixtures. (C) 2007 Elsevier B.V. All rights reserved.