Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637453
Title: CLAT crystals
Author: Jones, J. R.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1993
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Abstract:
We report here the results of investigations into three related but distinct aspects of studies on montmorillonites. The first examines the alumina pillaring of montmorillonite by the introduction of the so-called 'Keggin ion' via cation exchange. The level of pillar precursor ion introduced is controlled by inducing layer charge reduction by controlled calcination. Previously, neither the effective charge on the Keggin ion nor the pillar densities achieved were known with any certainty since the analyses of Al and Si present substantial difficulty. We have introduced a new technique to calculate the number of pillars introduced which we call 'isomorphous metal dilution'. This is based on analysis of Fe3+ and Mg2+, which is achieved with accuracy. The results are self consistent and establish that the Keggin ion charge here is 3+ , not 7+ as assumed previously. The next section explores the possibility of incorporating more Li+ into the layers of Texas montmorillonite during the process of lithiation. It involved successive calcination of Li+ exchanged clay, base regeneration of cation exchange capacities, further Li+ exchange and calcination, etc. This was successfully carried out five times, and enhanced the level of lithiation. However, it was established that this reaches a limit. Suggestions are offered to account for this. These clays also showed high solvent stability as compared to the parent material, a distinct commercial benefit. Finally, the catalytic alkylation of thiophene, has been investigated. C3 to C6 alk-1-enes and alkan-1-ols were employed as alkylating reagents. The broad range of reaction products have been characterised by GC/MS and by a comprehensive gas chromatographic study based on structural dependences of retention volume. Alkanols were shown to represent inefficient reagents. Alkenes on the other hand gave results establishing that, by suitable adjustment of temperature and relative reactant concentrations, highly competitive product yields and selectivity compared to conventional catalysts may be produced.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.637453  DOI: Not available
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