Hydrocracking of hydrocarbons with a presulfided ammonium crystalline zeolite cracking base promoted with a group viii metal

Claim 1

A PROCESS FOR HYDROCRACKING A HYDROCARBON FEEDSTOCK WHICH COMPRISES SUBJECTING SAID FEEDSTOCK PLUS ADDED HYDROGEN TO HYDROCRACKING CONDITIONS OF TEMPERATURE AND PRESSURE IN CONTACT WITH A CATALYST COMPRISING A ZEOLITIC, ALUMINO-SILICATE MOLECULAR SIEVE CRACKING BASE OF THE Y CRYSTAL TYPE UPON WHICH IS DEPOSITED A SMALL PROPORTION OF A GROUP VIII METAL HYDROGENATING PROMOTER, THE ZEOLITIC CATION CONTENT OF SAID CRACKING BASE COMPRISING A SUBSTANTIAL PROPORTION OF HYDROGEN IONS, SAID CATALYST HAVING BEEN PREPARED BY ION-EXCHANGING SAID GROUP VIII METAL INTO AN AMMONIUM FORM OF SAID ZEOLITIC CRACKING BASE AND DRYING THE SAME TO A WATER CONTENT BELOW ABOUT 25% BY WEIGHT, FOLLOWED BY (A) SULFIDING OF THE DRIED, ION-EXCHANGED, SULFIDED, AMMONIUM ZEOLITE COMPOSITE WITH HYDROGEN SULFIDE UNDER SUBSTANTIALLY ANHYDROUS CONDITIONS AT A TEMPERATURE BELOW ABOUT 500*F., AND THEN (B) REDUCING IN HYDROGEN AT AN ELEVATED TEMPERATURE TO CONVERT ZEOLITE AMMONIUM IONS TO HYDROGEN IONS.