The rhodium catalyzed hydroformylation of myrcene, limonene and camphene is achieved in a toluene/water biphasic system employing tris(3-sulfonatophenyl)phosphine, trisodium salt (TPPTS) as ancillary ligand as a function of the cationic surfactant cetyltrimethylammonium chloride (CTAC-) concentration. In some cases the observed conversion rates were superior to the similar homogeneous systems. The promotion effect of CTAC and its optimal concentration depends on the conformational characteristics of the substrate. For myrcene, a pronounced promotion effect is observed for CTAC concentrations around 2.5 x 10(-2) M, whereas for camphene there is an inhibition effect even at concentrations as low as 2.5 x 10(-3) M. (C) 2004 Elsevier B.V. All rights reserved.