Abstract: A mixture of aromatic hydrocarbons, comprising ethylbenzene and at least one xylene, is isomerized using a two reactor system to convert the ethylbenzene to compounds that may be removed from the aromatic hydrocarbon stream and to produce a product stream wherein the para-xylene concentration is approximately equal to the equilibrium ratio of the para-isomer. The catalyst present in the first reactor is one that is effective for ethylbenzene conversion with minimal xylene loss when operated under suitable conversion conditions, e.g., a catalyst comprising silica bound ZSM-5 that has been selectivated by one or more silicon impregnations or that has been coke selectivated. The catalyst present in the second reactor is one which is effective to catalyze xylene isomerization when operated under suitable conditions. Each of the catalysts of this invention may contain one or more hydrogenation or dehydrogenation components.

Abstract: Light olefins are converted to isoalkene-rich hydrocarbon products, e.g., isobutene and isoamylenes with zeolite MCM-22 catalyst.

Abstract: A novel catalyst composition is provided for catalytic cracking of a hydrocarbon oil to provide a product of increased octane number and increased C.sub.5 + gasoline content. The catalyst composition contains a large pore crystalline molecular sieve component and an MCM-22 zeolite component.

Abstract: A catalytic cracking process is disclosed using a catalyst comprising a framework dealuminate Y zeolite, which is rare earth and aluminum exchanged.

Abstract: The catalytic cracking of a hydrocarbon oil to provide a product of increased octane number and increased C.sub.5 + gasoline content is carried out employing a cracking catalyst composition containing both a large pore crystalline zeolite component and an MCM-22 zeolite component.

Abstract: The use of a catalyst containing Mn, a large pore crystalline molecular sieve, and optionally rare earths in catalytic cracking is disclosed. This catalyst gives high gasoline selectivity with low coke yields and is suitable for either gas oil or resid cracking applications.

Abstract: New catalyst compositions of superior hydrothermal stability, which evidence increased gasoline plus distillate yields, improved coke selectivity and reduced C.sub.4.sup.- gas yields, are based on framework dealuminated faujasitic zeolites having a framework silica to alumina molar ratio of from about 5 to 100. In a preferred embodiment, an "ultrastable Y" composited with a matrix, is subjected to a treatment with a source of aluminum and rare earth compounds followed by hydrothermal treatments to improve the hydrothermal stability and selectivity of the catalyst for catalytic cracking. This is evidenced by higher gasoline plus distillate yields and lower coke and gas production at lower catalyst useage per barrel of feed relative to commercial cracking catalysts currently being used.