Abstract: Molecular sieve compositions are prepared by extracting aluminum and substituting titanium and/or iron for extracted aluminum to give molecular sieve products containing framework titanium and/or iron atoms. The process of preparing the titanium and/or iron-containing molecular sieves involves contacting a starting zeolite with a solution or slurry of a fluoro salt of titanium and/or iron under effective process conditions to provide for aluminum extraction and substitution of titanium and/or iron.

Abstract: Crystalline zeolitic aluminosilicates having at least some of its original framework aluminum atoms replaced by extraneous silicon atoms and having a mole ratio of oxides in the dehydrated state of(0.85-1.1)M.sub.2/n O:Al.sub.2 O.sub.3 :xSiO.sub.2wherein M is a cation having a valence of "n"; "x" has a value greater than 6.0; has a x-ray powder diffraction pattern having at least the d-spacings of Table A; and has extraneous silicon atoms in the crystal lattice in the form of framework SiO.sub.4 tetrahedra. The novel zeolite aluminosilicates are employed in hydrocarbon conversion processes.

Abstract: Aluminum from AlO.sub.4 -tetrahedra of as-synthesized zeolites is extracted and substituted with silicon to form zeolite compositions having higher SiO.sub.2 /Al.sub.2 O.sub.3 molar ratios and exhibiting distinctive chemical and physical properties. The preparative procedure involves contact of the starting zeolite with an aqueous solution of a fluorosilicate salt using controlled proportions and temperature and pH conditions which avoid aluminum extraction without silicon substitution.

Abstract: Aluminum from AlO.sub.4 -tetrahedra of as-synthesized zeolites is extracted and substituted with silicon to form zeolite compositions having higher SiO.sub.2 /Al.sub.2 O.sub.3 molar ratios and exhibiting distinctive chemical and physical properties. The preparative procedure involves contact of the starting zeolite with an aqueous solution of a fluorosilicate salt using controlled proportions and temperature and pH conditions which avoid aluminum extraction without silicon substitution.