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Title: Computational investigations of the role of organic templating agents in zeolite synthesis.
Author: Stevens, Adrian Philip.
ISNI:       0000 0001 3481 6321
Awarding Body: University of Portsmouth
Current Institution: University of Portsmouth
Date of Award: 1996
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In this thesis, a number of molecular modelling techniques have been used to investigate the role of organic templating agents in the synthesis of zeolite microporous materials. Initially, molecular similarity tools were applied in order to investigate trends in the structural properties of templates. The results highlighted a strong correlation, showing that templates which facilitate the synthesis of the same zeolite, share similar dimensions. Subsequent manual docking studies, based on molecular graphics have helped to provide an insight into the basis for the observed relationships, revealing a close match between the dimensions of the templates and the topology of the channel systems of the microporous materials. A combined Monte Carlo / Simulated Annealing protocol was developed to predict in a rigorous manner, the location and orientation adopted by templates within periodic models of the host frameworks. This approach revealed that in addition to a strong shape-based relationship between template and zeolite, a further correlation was exhibited between templates, in the form of a `sub-shape' phenomena in the packing arrangements adopted within the microporous structures. In terms of the `Templating' theory of zeolite synthesis, this helped to rationalise previous experimental work which showed that some template molecules could facilitate the synthesis of more than one zeolite and also that some zeolites could be synthesised from a wide range of templates. Finally, a mechanism is proposed, linking template packing arrangements to extended defect stacking faults in two zeolite materials, Beta and NU-86.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Organic chemistry