There is provided a catalyst composition having improved hydrothermal
stability for the catalytic cracking of a hydrocarbon feedstock to
selectively produce propylene. The catalyst composition comprises a first
crystalline molecular sieve selected from the group consisting of IM-5,
MWW, ITH, FER, MFS, AEL, and AFO and an effective amount of a
stabilization metal (copper, zirconium, or mixtures thereof) exchanged
into the molecular sieve. The catalyst finds application in the cracking
of naphtha and heavy hydrocarbon feedstocks. When used in the catalytic
cracking of heavier hydrocarbon feedstocks, the catalyst composition
preferably comprises a second molecular sieve having a pore size that is
greater than the pore size of the first molecular sieve. The process is
carried out by contacting a feedstock containing hydrocarbons having at
least 4 carbon atoms is contacted, under catalytic cracking conditions,
with the catalyst composition.