Investigation of the dealumination of high silica zeolite A (ZK-4) by 29Si magic-angle-spinning n.m.r. spectroscopy

Abstract

The high-field (11.7 T)²⁹Si magic-angle-spinning n.m.r. spectrum of the completely siliceous analogue of zeolite A, prepared by hydrothermally dealuminating zeolite ZK-4, which consists of a single sharp sharp resonance at –112.9 p.p.m. from Me₄Si is indicative of the removal of all the lattice aluminium and retention of the crystalline framework; powder X-ray diffraction measurements confirm that this novel material retains the framework topology of zeolite A.