The kinetics of the [Rh-2(mu-(SBu)-Bu-t)(2)(CO)(2)(TPPTS)(2)] catalyzed hydroformylation of I-octene by supported aqueous phase catalysis has been investigated under mild conditions (0.5-1 MPa, 353-373 K). The effect of 1-octene and catalyst concentration and partial pressure of hydrogen and carbon monoxide on the rate of reaction has been studied. The rate was found to be first-order with respect to catalyst concentration and partial order with respect to partial pressure of hydrogen. However, when partial pressure of carbon monoxide and 1-octene concentration increased, the rate showed a typical case of substrate-inhibited kinetics. A rate equation has been proposed, considering that each particle of supported aqueous phase catalyst is a microreactor, where the reaction takes place at the aqueous/organic interface. The kinetic model showed the good agreement with the experimental data, being the average relative error of estimation less than 7%. The kinetic parameters have been evaluated for different temperatures. The activation energy was found to be 71 kJ/mol. (C) 2003 Elsevier Science B.V. All rights reserved.