A NEW MICROPOROUS POLYMORPH OF SILICA ISOMORPHOUS TO ZEOLITE MCM-22

Authors
CAMBLOR MA CORELL C CORMA A DIAZCABANAS MJ NICOLOPOULOS S GONZALEZCALBET JM VALLETREGI M
Citation
Ma. Camblor et al., A NEW MICROPOROUS POLYMORPH OF SILICA ISOMORPHOUS TO ZEOLITE MCM-22, Chemistry of materials, 8(10), 1996, pp. 2415
Citations number
18
Categorie Soggetti
Chemistry Physical","Material Science
Journal title
Chemistry of materials → ACNP
ISSN journal
08974756
Volume
8
Issue
10
Year of publication
1996
Database
ISI
SICI code
0897-4756(1996)8:10<2415:ANMPOS>2.0.ZU;2-Q
Abstract
ITQ-1, a microporous pure-silica polymorph isomorphous to zeolite MCM- 22, forms upon calcination of a layered precursor obtained by hydrothe rmal synthesis. Calcined ITQ-1 contains a remarkably small concentrati on of connectivity defects (congruent to 7 Si(OSi)(3)OH mol %) in cont rast to uncalcined ITQ-1 (congruent to 30%). Si-29 NMR spectra, which are in good agreement with the structure proposed for MCM-22, demonstr ate the defects are not randomly distributed in the layered precursor but arise mostly from unconnected T1-O-T1 and T2-O-T3 bonds.