Synthesis and analysis of polyphenyl compounds and their derivatives

Student thesis: Doctoral ThesisDoctor of Philosophy

Abstract

This thesis is concerned with the study of polyphenyl compounds and their derivatives, and throughout the work is the overarching theme of analysis and understanding of complex mixtures. The analysis of complex mixtures is not only an academic pursuit but something of value to industry. Individual components of complex systems may have advantageous or detrimental effects to the overall performance of materials. Without suitable analysis the development of optimal products is not possible. This work begins to address the identification and understanding of aromatic or aromatic derived mixtures which are used in, or of interest to industrial applications.

Chapter one focuses on the homocoupling of methyl benzoate, which yields six isomeric products. The desired 4,4’’-biphenyl dicarboxylate product is of interest as a specialist monomer. The aim of synthesis via a double C-H activation was challenging and ultimately no improvement on the literature precedents was made.

Chapter two addresses the challenges in studying purely aromatic compounds of closely related structures. The pyrolysis of benzene is an industrial process which produces a complex mixture with little control over selectivity. The aim of this chapter was to understand the possible products of pyrolysis. This was achieved by the synthesis of seven aromatic hydrocarbons of the skeleton C24. Using HPLC a method for the rapid analysis of 14 closely related compounds was developed using commercially available stationary phases. A comparison of alkyl and aromatic phases was made. Lastly a series of NMR techniques were used to provide spectral data on linear quaterphenyl isomers, allowing each isomer to be identified from a proton spectrum.

Chapter three is concerned with the synthesis of the partially and fully hydrogenated terphenyls. The focus is the synthesis of para substituted three-ring structures, from fully aromatic p-terphenyl to fully saturated p-tercyclohexyl and the intermediary partially reduced compounds. These compounds are successfully synthesised. The methods used are extended to some equivalent isomers of ortho and meta substitution. These compounds can be used to identify regio- and stereoisomers and closely related compounds from the complex mixtures in which they are found.

Thesis embargoed until 31 December 2023.
Date of AwardDec 2021
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SponsorsEastman Chemical Company
SupervisorMark Muldoon (Supervisor) & Panagiotis Manesiotis (Supervisor)

Keywords

  • Polyphenyls
  • quaterphenyls
  • terphenyls
  • reduced terphenyls
  • analytical methods
  • 2D NMR
  • hydrocarbon

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