Impregnated platinum-alumina catalysts

Claim 1

A HYDROCARBON-CONVERSION PROCESS WHEREIN A HYDROCARBON CHARGING STOCK IS CONTACTED UNDER CONVERSION CONDITIONS WITH A SINGLY CALCINED PELLETED ALUMINA-SUPPORTED PLATINUM CATALYST, PREPARED BY ADDING AN ALKALINE SUBSTANCE TO PEPTIZED ALUMINA IN A QUANTITY SUFFICIENT TO RAISE THE PH THEREOF TO A LEVEL WITHIN THE RANGE OF ABOUT 8.5 TO 12, MAINTAINING THE RESULTING MIXTURE AT A PH WITHIN SAID RANGE AND AT A TEMPERATURE BETWEEN ABOUT 50 AND 260*F. FOR A PERIOD IN EXCESS OF ABOUT 1 HOUR, WHEREBY SAID HYDROSOL IS CONVERTED INTO A FILTERABLE SLURRY OF SOLID, HYDROUS ALUMINA, SEPARATING SAID SOLID, HYDROUS ALUMINA FROM SAID SLURRY, DRYING THE TREATED ALUMINA TO A VOLATILES CONTENT BETWEEN ABOUT 15 AND 50 PERCENT BY WEIGHT, WET BASIS, CRUSHING THE DRIED ALUMINA, UNIFORMLY INCORPORATING A LIPOPHILIC PELLETING LUBRICANT THEREIN, FORMING THE LUBRICATED ALUMINA INTO PELLETS, UNIFORMLY IMPREGENATING THE PELLETED LUBRICATED ALUMINA TO A PLATINUM LEVEL BETWEEN ABOUT 0.05 AND 1 PERCENT BY WEIGHT, BASED ON DRY AL2O3, WITH A SOLUTION OF A PLATINUM COMPOUND IN AN ORGANIC SOLVENT CAPABLE OF WETTING SAID PELLETING LUBRICANT, AND DRYING AND CALCINING IN AIR WHEREBY, THE LUBRICANT IS REMOVED.