The hydroformylation of 1-dodecene was studied using Rh(acac)(CO)(2) and a ligand as a catalyst in a thermomorphic multicomponent solvent (TMS) system consisting of N,N-dimethylformamide, decane and the olefin. High n-aldehyde/iso-aldehydes ratios were obtained with the bidentate phosphite ligand biphephos. In systematic preliminary investigations suitable catalyst/ligand-ratios and catalyst concentrations were determined. In order to derive a simplified reaction network, semi-batch experiments were performed measuring responses to perturbations of pressure and feed composition. From the results obtained the main branches of the reaction network could be identified comprising also isomerizations and hydrogenations of n- and iso-dodecenes. For this simplified reaction network a catalytic cycle is suggested providing the basis for the formulation of a more detailed mechanistic kinetic model. (C) 2013 Elsevier B.V. All rights reserved.