An investigation has been made of the hydroformylation of propylene tetramers in the presence of cobalt complexes Co-2(CO)(8) and Co-2(CO)(8) + P(C12H25)(3) and a cobalt carbonyl-pyridine complex, The kinetics of the main reaction (the hydroformylation of C-12 olefins) and secondary reactions has been studied. A mathematical model of the process has been created. The use of cobalt complexes as hydroformylation catalyst precursors is ineffective owing to the intense secondary reactions that occur with high degrees of conversion of the initial olefin. The introduction of pyridine into the reaction in the form of a cobalt carbonyl-pyridine complex makes it possible to increase the target product yield considerably and to carry out the parallel hydrogenation of the carbonyl group of the aldehyde to an alcohol.