Gallosilicate zeolites from porotectosilicate precursors: the ready preparation of gallo-ZSM-11 from silicalite-II

Abstract

Powder X-ray diffractometry, multinuclear magic-angle spinning n.m.r. and i.r. spectroscopy, electron microscopy, and gas adsorption studies establish that silicalite-II (Si/Al ca.1050) undergoes facile substitution of Ga³⁺ for Si⁴⁺ at tetrahedral sites, with retention of the framework structure, on exposure to aqueous solutions of NaGaO₂: the method also works for many other siliceous zeolitic structures.