Abstract: A process for the manufacture of a modified aluminosilicate zeolite is disclosed which includes contacting a starting zeolite in an aqueous phase with a dealuminating agent at a pH value of lower than 4 in the presence of a soluble silica. A novel zeolite composition is also disclosed which has increased acid and thermal stability.

Abstract: A cracking catalyst for hydrocarbons with superior selectivity to gasoline production and greater metals tolerance comprising a porous inorganic oxide matrix composited with a crystalline aluminosilicate zeolite and a phosphorus-containing alumina in the form of small lumps.

Abstract: A catalyst composition that is prepared by adding phosphorus to a hydrogel slurry of fibrous pseudoboehmite having a diameter of 0.05-0.3 .mu. and a length of 0.5 .mu. or more, mixing a crystalline aluminosilicate zeolite and a clay mineral therewith, spray drying this mixture and calcining, and has a total pore volume (PV) of 0.3-0.7 cc/g, a volume (PVa) occupied by pores whose diameter is 600 .ANG. or less of 0.3-0.7 cc/g and a PVb/PVa ratio where PV-PVa=PVb of 0.5-2.0, displays superior activity, selectivity and metals tolerance when used in the fluid cat-cracking of heavy hydrocarbon oils, in particular residual oils.

Abstract: In a catalytic cracking process for heavy oil which comprises contacting a heavy oil with a particulate mixture of a crystalline aluminosilicate-containing cracking catalyst particle and an alumina particle and/or a phosphorus-containing alumina particle mixed in the weight ratio of 80/20-20/80, under cracking conditions, metal contaminants contained in said feed oil are captured preferentially by said alumina particle and/or a phosporous-containing alumina particle, and the coexistent cracking catalyst is poisoned only to a reduced degree by metal contaminants.

Abstract: According to the present invention, a catalyst composition for use in cracking hydrocarbon can be prepared by spray drying an aqueous slurry containing a flash calcined alumina obtained by contacting an aluminum hydroxide with a hot air of 350.degree.-700.degree. C. in a short time within 5 seconds, kaolin, a precursor substance of a silica-system matrix and a crystalline aluminosilicate. Since this catalyst composition contains the flash calcined alumina and kaolin in addition to the siliceous matrix and the crystalline aluminosilicate, it can exhibit an excellent selectivity for production of intermediate fractions such as kerosene, gas oil and the like, when used for catalytic cracking of hydrocarbon.

Abstract: A catalyst composition suitable for catalytic cracking of a heavy hydrocarbon oil containing large amounts of metal contaminants is prepared by the steps of spray-drying an aqueous slurry containing a flash calcined alumina obtained by contacting an aluminum hydroxide prepared Bayer's process with a hot air of 350.degree.-700.degree. C. for 5 seconds or less, clay being predominantly composed of silica and alumina, a precursor of a siliceous inorganic oxide and a crystalline aluminosilicate; washing this particle until the alkali metal content therein is reduced to 1.0 wt % or less as oxide; and thereafter incorporating a rare earth component in the particle.