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Published December 2008 | public
Journal Article

A case study of divergent structure directing effects of geometric isomers: the discovery of a new structure directing agent for an all-silica RTH zeolite prepared in fluoride media

Abstract

This report describes experimental work that is a follow-up to predictions presented in a previous study on the zeolite SSZ-73 (SAS). In that study we observed trace amounts of RTH phases in some of our preparations of SSZ-73. We hypothesized that the RTH phase could be due to a geometric isomer of the polycyclic structure directing agent (SDA) used to prepare SSZ-73. In this work we have performed detailed NMR analyses that confirm the presumed isomeric structure of the molecule used in the preparation of SSZ-73. We have then used an alternate procedure to prepare an SDA that is enriched (66–75%) in the geometric isomer believed to be responsible for the RTH-type phase. Syntheses with this SDA in fluoride media give an RTH zeolite as the major product. Solid-state NMR of the RTH products indicates the isomers are occluded in the final product in approximately the same ratio that they are present in the synthesis preparation.

Additional Information

© 2008 Elsevier. Received 7 January 2008; accepted 2 April 2008. Available online 11 April 2008. This work was supported by the Chevron Energy Technology Company. We thank Tom Rea and Glenn Menard for collection of the SEM data. We are grateful to G.L. Scheuerman and C.R. Wilson for support of the new materials research program at Chevron. The NMR facility at Caltech was supported by the National Science Foundation (NSF) under Grant No. 9724240 and partially supported by the MRSEC Program of the NSF under Award Number DMR-0520565.

Additional details

Created:
August 22, 2023
Modified:
October 18, 2023