| abstract |
Supported hydroprocessing catalysts comprising a sulfide of trivalent chromium and molybdenum or tungsten which optionally may contain one or more promotor metals such as Co, Fe, Ni and mixture thereof. These catalysts are obtained by comprising a preselected quantity of support material with a precursor salt containing a tetrathiometallate anion of Mo or W and a cation comprising trivalent chromium and, optionally, one or more promoter metals wherein both said trivalent chromium and promoter metal are chelated by at least one neutral, nitrogen-containing polydentate ligand and heating the composite in the presence of sulfur and hydrogen in an oxygen-free atmosphere. These catalysts have high selectivity for nitrogen removal. The chromium and promoter metal do not have to be in the same cation. |