Hydroformylation of 1-dodecene catalyzed by water-soluble rhodium-phosphine complex, RhCl(CO)(TPPTS)(2) (TPPTS: P(m-C6H4SO3Na)), in the presence of various mixed micelles was investigated. When either an anionic surfactant sodium dodecyl sulfate (SDS) or dodecylbenzonesulphonate (DBS), a nonionic surfactant Triton X-100 or Brij 35, or alcohol was added into cationic surfactant cetyl pyrindium bromide (CPB) solution, a mixed micelle formed. The decrease in critical micelle concentration (CMC) and the increase in solubilization of 1-dodecene in the mixed micelle were observed. Hydroformylation of 1-dodecene exhibited higher conversion and higher regioselectivity in the mixed micellar solution than in the single micelle of CPB. The synergistic mechanism of two different surfactants was discussed. (C) 2002 Elsevier Science B.V. All rights reserved.