Abstract <p>Results on the conversion of vacuum residue in the presence of a regenerated spent alumina-supported cobalt–molybdenum hydrotreating catalyst and hydrogen donor solvents are presented. The catalyst sample is bifunctional and initiates hydrogen transfer, cracking, and isomerization reactions. Hydrogen donor solvents combine physical and chemical effects to reduce coke formation. The physicochemical properties of the catalyst sample, the vacuum residue, and the solvents were analyzed. The experiments were carried out in an autoclave. The process efficiency was evaluated by the increase in the yield of light fractions and the decrease in coke yield. The effect of gaseous hydrogen on the cracking of the vacuum residue was evaluated. The effect of hydrogen donor solvents on the system was examined. Comparative experiments were performed on the cracking of the vacuum residue with hydrotreated light catalytic cracking gas oil and in the presence of the corresponding sample that was not hydrotreated. The effect of the fractional composition of the hydrogen donor solvent on the process results was evaluated. The optimal solvent content in the system was determined. Material balances for each experimental series were presented, with calculation of the increase in the yield of light fractions and the decrease in coke yield relative to thermal cracking. The physicochemical properties of the obtained narrow fractions were determined, including density, sulfur content, iodine number, refractive index, kinematic viscosity, and aromatic hydrocarbon content for diesel fractions, as well as the kinematic viscosity of cracking residues. The most effective process conditions were identified. The prospects for implementing this process in refinery operations were assessed.</p>