Abstract: There is provided a method for preparing an acidic solid comprising a Group IVB metal oxide modified with an oxyanion of a Group VIB metal. An example of this acidic solid is zirconia, modified with tungstate. This modified solid oxide may be used as a catalyst, for example, to isomerize C.sub.4 to C.sub.8 paraffins. The method for preparing this acidic solid involves contacting a hydrated oxide of a Group IVB metal under hydrothermal conditions, such as reflux conditions, prior to contact of the hydrated oxide with an aqueous solution comprising a source of an oxyanion of a Group VIB metal.

Abstract: A heavy aromatics feed is converted to lighter aromatics products, such as benzene, toluene and xylenes by contacting a C.sub.9 + aromatics fraction and benzene and/or toluene over a catalyst comprising a zeolite, such as ZSM-12, and a hydrogenation component, preferably platinum. The catalyst, complete with hydrogenation component, is treated to reduce aromatics loss. Treatment includes exposure to steam and/or sulfur after incorporation of the hydrogenation component. For additional stability and aromatics retention the steamed and/or sulfur treated catalyst is sulfided by cofeeding a source of sulfur. In a further embodiment of the invention a low hydrogen partial pressure is employed to retain aromatics.

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: A mixture of aromatic hydrocarbons, comprising ethylbenzene and at least one xylene, is treated to convert the ethylbenzene to compounds that may be removed from the aromatic hydrocarbon stream and to isomerize any xylenes present. The ethylbenzene conversion catalyst is one that is effective for ethylbenzene conversion with minimal xylene loss, e.g., a silica bound intermediate pore size zeolite that has been selectivated. The xylene isomerization catalyst is one which is effective to catalyze xylene isomerization. Each of the catalysts of this invention may contain one or more hydrogenation or dehydrogenation components.

Abstract: There is provided zeolite catalyst, which is first selectivated with a siliceous material and then treated with an aqueous solution comprising ammonium or organoammonium ions under ion exchange conditions.

Abstract: There is provided a zeolite catalyst, which is first selectivated with a siliceous material and then washed with a liquid. The washing step may comprise slurrying the catalyst in water and recovering the washed catalyst by filtration.