Preparation of chromia-containing hydrogels

Claim 1

A METHOD FOR PREPARING A CATALYTIC COMPOSITE CONSISTING ESSENTIALLY OF A MAJOR PROPORTION OF CHROMIA AND A MINOR PROPORTION OF AT LEAST ONE OXIDE OF A METAL SELECTED FROM THE GROUP CONSISTING OF ALUMINUM, ZIRCONIUM, TITANIUM, MAGNESIUM, BERYLLIUM , MOLYBDENUM, AND THORIUM, WHICH COMPRISES FORMING A HYDROSOL HAVING A PH OF LESS THAN 4 AND CHARACTERIZED BY AN INHERENT CAPACITY TO SET TO A HYDROGEL WITHOUT ADDITION TO OR SUBTRACTION FROM SAID SOL OF ANY SUBSTANCES, BY ADMIXING AN AQUEOUS SOLUTION OF CHROMIC ACID WITH AN ALCOHOLIC SOLUTION OF A METAL ALCOHOLATE DERIVED FROM A METAL OF THE AFORESAID GROUP AND AN ALCOHOL OF LESS THAN 5 CARBON ATOMS, SAID SOLUTION OF CHROMIC ACID SERVING TO PROVIDE THE SOURCE OF SAID CHROMIA, TO CATALYZE THE HYDROLYSIS, OF SAID ALCOHOLATE AND TO PEPTIZE THE METAL OXIDE OBTAINED IN THE HYDROLYSIS, RETAINING IN TION OCCURS, DRYING THE RESULTING HYDROGEL, CONTACTING THE DRIED HYDROGEL WITH A REDUCING GAS WHILE SIMULTANEOUSLY RAISING THE TEMPERATURE THEREOF TO 400-600*F. AT A SUFFICIENTLY SLOW RATE THAT UNGLOWED CONDITION OF THE CHROMIA COMPONENT IS PRESERVED, MAINTAINING THE GEL IN THE REDUCING ATMOSPHERE AT THE AFORESAID TEMPERATURE UNTIL REDUCTION OF HEXAVALENT CHROMIUM PRESENT IN THE GEL IN SUBSTANTIALLY COMPLETE, THEN SLOWLY HEATING THE GEL IN THE REDUCING ATMOSPHERE TO A TEMPERATURE IN THE RANGE OF 900 TO 1200* F. AND THEREAFTER COOLING THE RESULTING HEAT-TREATED GEL

Claim 2

A METHOD FOR PREPARING A CATALYTIC COMPOSITE CONSISTING ESSENTIALLY OF A MAJOR PROPORTION OF CHROMIA AND A MINOR PROPORTION OF AT LEAST ONE OXIDE OF A METAL SELECTED FROM THE GROUP CONSISTING OF ALUMINUM, ZIRCONIUM, TITANIUM, MAGNESIUM, BERYLLIUM , MOLYBDENUM, AND THORIUM, WHICH COMPRISES FORMING A HYDROSOL HAVING A PH OF LESS THAN 4 AND CHARACTERIZED BY AN INHERENT CAPACITY TO SET TO A HYDROGEL WITHOUT ADDITION TO OR SUBTRACTION FROM SAID SOL OF ANY SUBSTANCES, BY ADMIXING AN AQUEOUS SOLUTION OF CHROMIC ACID WITH AN ALCOHOLIC SOLUTION OF A METAL ALCOHOLATE DERIVED FROM A METAL OF THE AFORESAID GROUP AND AN ALCOHOL OF LESS THAN 5 CARBON ATOMS, SAID SOLUTION OF CHROMIC ACID SERVING TO PROVIDE THE SOURCE OF SAID CHROMIA, TO CATALYZE THE HYDROLYSIS, OF SAID ALCOHOLATE AND TO PEPTIZE THE METAL OXIDE OBTAINED IN THE HYDROLYSIS, RETAINING IN TION OCCURS, DRYING THE RESULTING HYDROGEL, CONTACTING THE DRIED HYDROGEL WITH A REDUCING GAS WHILE SIMULTANEOUSLY RAISING THE TEMPERATURE THEREOF TO 400-600*F. AT A SUFFICIENTLY SLOW RATE THAT UNGLOWED CONDITION OF THE CHROMIA COMPONENT IS PRESERVED, MAINTAINING THE GEL IN THE REDUCING ATMOSPHERE AT THE AFORESAID TEMPERATURE UNTIL REDUCTION OF HEXAVALENT CHROMIUM PRESENT IN THE GEL IN SUBSTANTIALLY COMPLETE, THEN SLOWLY HEATING THE GEL IN THE REDUCING ATMOSPHERE TO A TEMPERATURE IN THE RANGE OF 900 TO 1200* F. AND THEREAFTER COOLING THE RESULTING HEAT-TREATED GEL