This thesis describes various applications of high field n.m.r. for the elucidation of coal structure, and concentrates on discovering the chemical environments of the heteroatoms in coal i.e. those elements other than carbon and hydrogen. Chapter 2 describes how hydroxyl groups may be converted to trimethyl siloxyl groups, observation of which by 29si n.m.r. allows one to determine the types of hydroxyl functionalities present in the original material. Such derivatization methods are well known. However trimethyl siloxyl groups give 29si resonances that have predictable chemical shifts and so the derivative spectra of complex coal tars and extracts are easy to interpret. Using this technique we have investigated the nature of hydroxyl groups in a rank series of coal tars. This has given us some insight into the way the hydroxyls are affected by coalification. Chapter 3 is a demonstration of the use of n.m.r. as a detector for H.P.L.C. This has two principle novelties over previous work. Firstly it does not involve building a special probe and secondly, the data is presented as a contour plot of intensity vs. retention time and chemical shift. This method has been used to investigate the nature of several tar fractions and complements the derivatization technique of chapter 2. The final chapter shows how the nature of sodium in coal was determined by 23Na MAS-NMR. By using the information contained in the chemical shift and linewidths of raw and dried coal it was concluded that sodium exists bound to the surface of coal pores by oxygen functions such as carboxylates and phenoxides. It does not exist as sodium chloride microcrystals as once thought.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:278713 |
| Date | January 1988 |
| Creators | Ratcliffe, Giles Stuart |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/107456/ |
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