Organic-functionalized molecular sieves (OFMSs). II. Synthesis, characterization and the transformation of OFMSs containing non-polar functional groups into solid acids

Organic-functionalized molecular sieves (OFMSs) with a beta-type structure (*BEA) containing intracrystalline phenethyl (PE) groups were synthesized and characterized by X-ray diffraction, thermogravimetric analysis, FT Raman spectroscopy, Si-29, C-13 and Al-27 solid-state nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy, bulk elemental analysis, scanning electron microscopy and physisorption techniques. The OFMSs are synthesized from monomeric silicon sources such as tetraethylorthosilicate and phenethyltrimelhoxysilane and via the solid-state conversion of extracted, PE-functionalized MCM-41. Occluded structure-directing agent (tetraethylammonium fluoride; TEAF) is removed by solvent extraction techniques. By varying the extraction conditions, OFMSs with varying hydrophobicity and porosity are synthesized. Bulk and surface elemental analysis indicate that there is an even distribution of organic functionalities throughout the material at levels of PE incorporation below 5% (silicon basis). The phenethyl groups are sulfonated using SO3 vapor to produce a microporous solid containing intracrystalline sulfonic acids. (C) 1999 Elsevier Science B.V. All rights reserved.