Process for preparing silica alumina catalyst and catalyst prepared thereby

Claim 1

A SILICA ALUMINA CATALYST HAVING IMPROVED ACTIVITY SUBSEQUENT TO STEAMING SAID CATALYST, COMPRISING A PREDOMINANTLY KAOLIN-DERIVED SILICA CONTENT, AND A MINOR AMOUNT OF KAOLIN-DERIVED ALUMINA, SAID CATALYST BEING PREPARED BY A PROCESS COMPRISING: (1) DIGESTING KAOLIN WITH SULFURIC ACID UNTIL FROM ABOUT 75% TO ABOUT 90% OF THE AL2O3 CONTENT OF SAID KAOLIN IS LEACHED THEREFROM FORMING AN ALUMINUM SALT-CONTAINING SUPERNATANT SOLUTION, PRODUCING A RESIDUE COMPRISING ACID-TREATED KAOLIN; (2) SEPARATING SAID RESIDUE FROM SAID LEACHING ACID AND FROM SAID SUPERNATANT SOLUTION; (3) MIXING SAID SEPARATED RESIDUE WITH AN AQUEOUS ALUMINUM SULFATE SOLUTION, AND THEREBY FORMING A MIXTURE; (4) ADDING AMMONIA TO SAID MIXTURE, SAID AMMONIA ADDITION BEING IN AN AMOUNT SUFFICIENT TO SUBSTANTIALLY MAINTAIN THE PH OF SAID MIXTURE BETWEEN ABOUT 5.5 AND ABOUT 7.5, THEREBY PRECIPITATING AL2O3 FROM SAID AQUEOUS SOLUTION; (5) SEPARATING FROM SAID MIXTURE, SAID PRECIPITATE-CONTAINING KAOLIN RESIDUE; AND (6) WASHING AND DRYING SAID SEPARATED PRECIPITATE-CONTAINING RESIDUE.