Solvent effects on the reaction equilibrium of the 1-dodecene hydroformylation in a decane/N,N-dimethylformamide solvent system is investigated. The reaction was performed at different decane/N,N-dimethylformamide ratios and at temperatures between 368 K and 388 K. The equilibrium concentrations of all reactants and products were determined experimentally. The enthalpy and Gibbs energy of this reaction at the ideal-gas standard state were determined by quantum-chemical calculations in good agreement with literature data. Moreover, quantum-chemically calculated standard Gibbs energies of reaction at infinite dilution in liquid decane/DMF-solvent mixtures allowed a qualitative prediction of the solvent effect on the equilibrium concentrations. Based on the standard Gibbs energy of reaction at the ideal-gas standard state and on fugacity coefficients calculated using the Perturbed-Chain Statistical Associating Fluid Theory, the equilibrium concentrations of reactants and products for the 1-dodecene hydroformylation performed in decane/N,N-dimethylformamide mixtures of different compositions could be predicted in very good agreement with experimental data. (c) 2017 American Institute of Chemical Engineers AIChE J, 63: 4576-4585, 2017