Hydroformylation of 1-dodecenc in a biphasic system using water-soluble rhodium catalyst RhCl(CO)(TPPTS)(2) [TPPTS: tri(sodium-m-sulfonatophenyl) phosphine] was investigated. The cationic surfactant cetyltrimethyl ammonium bromide (CTAB) was used to enhance the reaction rate of long chain olefin and the ratio of normal/isomeric aldehyde. Experiments were carried out semi-batchwise in a 500 ml Stirred autoclave at 100 degreesC and 1.1 MPa. An orthogonal experimental design was adopted for analyzing the effects of agitation intensity, 1-dodecene concentration, surfactant concentration and organic/water volume ratio on the macro-kinetics and regioselectivity. Several agitation configurations for improving the mixing, dispersion and interphase mass transfer of this 'gas-liquid-liquid reaction system were tested and higher hydroformylation rate and regioselectivity were achieved. The relationship between the extent of emulsification of reaction mixture and the performance of hydroformylation reaction was also studied. Empirical macro-kinetic equations for the initial rate and the correlation of normal/isomeric aldehyde ratio are proposed, which represented the experimental data reasonably well. (C) 2002 Elsevier Science B.V. All rights reserved.