Xpreparation o of silica-alumina base

Claim 1

A PROCESS FOR EFFECTING REFORMATING OF PETROLEUM NAPHTHAS, WHICH COMPRISES CONTACTING A PETROLEUM NAPTHA WITH A CATALYST COMPRISING CHROMIUM OXIDE SUPPORTED ON A SILICA-ALUMINA SUPPORT IN WHICH SILICA AND SLUMINA ARE PRESENT IN A MOLE RATIO FALLING WITHIN THE RANGE VARYING BETWEEN ABOUT 10:90 AND ABOUT 30:70, RESPECTIVELY, OBTAINED BY EFFECTING THE COPRECIPITATION OF HYDROUS SILICON OXIDE AND HYDROUS ALUMINUM OXIDE AT A PH VARYING BETWEEN ABOUT 9.5 AND ABOUT 11.5, TO PRODUCE A MIXTURE OF COPRECIPITATE HYDROUS SILICON OXIDE AND HYDROUS ALUMINUM OXIDE, AGING SAID MIXTURE AT SAID PH FOR A PERIOD OF TIME FALLING WITHIN THE RANGE VARYING FROM ABOUT 4 HOURS TO ABOUT 24 HOURS, WASHING SAID MIXTURE TO REMOVE WATER-SOLUBLE IMPUTITIES, DRRYING SAID MIXTURE, AND CALCINING SAID MIXTURE, SAID CONTACTING TAKING PLACE AT A TEMPERATURE VARYING BETWEEN ABOUT 900* F. AND ABOUT 1050* F., AND AT A PRESSURE VARYING BETWEEN ATMOSPHERIC AND ABOUT 65 POUNDS PER SQUARE INCH.