Abstract: This invention is drawn to a process for isomerizing a non-equilibrium mixture of xylenes and ethylbenzene using a silicoaluminophosphate molecular sieve which is enriched in framework silicon at the surface, resulting in a greater yield of para-xylene compared to prior-art processes.

Abstract: A crystalline microporous organosilicate having the composition in terms of moles of oxides of:R.sub.2 O : 0-1.5 M.sub.2 O: <0.05 Al.sub.2 O.sub.3 : 40-70 SiO.sub.2 : x H.sub.2 Owherein R represents a tetraethylammonium cation, M is an alkali metal cation and x has a value of 0 to 15 depending upon the degree of hydration of the composition. The organosilicate is prepared hydrothermally using a reaction mixture comprising tetraethylammonium cations, alkali metal cations, water and a reactive source of silica. The crystalline orgnaosilicates are useful as adsorbents and, in their catalytically active form, as catalysts for organic compound formation.

Abstract: A novel crystalline silica composition having uniform pore dimensions of approximately 6 Angstrom units is prepared by calcining a crystalline hydrated alkylonium silicate prepared hydrothermally from a reaction mixture containing as essential reagents, water, amorphous silica and a quaternary ammonium compound at a pH of at least 10. The crystalline silica, because of its uniform pore structure, is capable of making size-selective separations of molecular species, but neither it nor its silicate precursor exhibit ion-exchange properties.This absorbent has a very useful hydrophobic/organophilic characteristic which permits its use in selectively adsorbing organic materials from water, either in liquid or vapor phase.