Ligand structure effect in oil-soluble phosphorus-containing molybdenum precursors for slurry-phase hydrocracking of heavy oil

•Mo precursors were used for the slurry-phase hydrocracking of vacuum residue.•The effects of P-containing ligands on the resulting MoS2 catalysts were evaluated.•A new method of measuring solubility parameters was used to determine dispersibility.•Precursor solubility was key for the performance of the resulting MoS2 catalyst.•The Mo triethylphosphite precursor improved product distribution and quality.