CATALYST COMPRISING A ZEOLITE PARTIALLY COATED WITH A SECOND ZEOLITE, ITS USE FOR HYDROCARBON CONVERSION

摘要

There is provided a coated zeolite catalyst in which the accessiblility of the acid sites on the external surfaces of the zeolite is controlled and a process for converting hydrocarbons utilizing the coated zeolite catalyst. The zeolite catalyst comprises core crystals of a first zeolite and a discontinuous layer of smaller size second crystals of a second zeolite which cover at least a portion of the external surface of the first crystals. The coated zeolite catalyst finds particular application in hydrocarbon conversion processes where catalyst activity in combination with zoelite structure are important for reaction selectivity, e.g., catalytic cracking, alkylation, disproportional of toluene, isomerization, and transalkylation reactions.