The catalytic reactions of a wide range of organic compounds with ion-exchanged bentonites have been investigated. Subsequent product analysis by modern analytical methods including gas-liquid chromatography, mass spectrometry, the combined technique of gas chromatography and mass spectrometry and nuclear magnetic resonance has established that a number of the catalytic reactions discovered are unique in the sense that although nominally feasible in solution reaction systems, they do not, in practice, occur. This research has shown that alkenes can react with intercalated water in the sheet silicate to produce branched chain ethers and that both alkanols and carboxylic acids can react with alkenes under the influence of the sheet silicate catalyst to furnish high yields of ethers and esters respectively. The sheet silicate has also been shown to catalyse the self condensation of alkan-1-ols to ethers, primary amines to secondary amines and thiols to thioethers. Benzyl alcohol and 2-hydroxymethylthiophene have been converted by the influence of the catalyst into high polymeric materials by self condensation processes. The work has revealed that a wide range of both known and novel types of organic chemical reactions are efficiently catalysed by certain cation-exchanged bentonites and that intercalation is a prerequisite. From this survey a mechanistic generalisation has emerged in which the role of protons in the catalysis is crucial and the attack of a nucleophile on a protonated species is a key mechanistic process.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:638624 |
| Date | January 1980 |
| Creators | Rayanakorn, M. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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