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Title: Analysis and reactions of cyclopropenoids with rhodium complexes.
Author: Jobanputra, Rajendra N.
ISNI:       0000 0001 3590 7882
Awarding Body: Kingston Polytechnic
Current Institution: Kingston University
Date of Award: 1989
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cyclopropene fatty acids (CPEFA) and cyclopropane fatty: acids (CPAFA) occur as glycerides in many plant families and the former are of particular interest because of their adverse physiological effects. The cyclopropenoid seed oil Gossypium hirsutum (cottonseed) and Ceiba pentandra (kapok) are widely used to provide food for man and animals. Methods currently described in the literature for the determination of CPEFA particularly at low levels, are either inaccurate or are criticised due to the complicated nature of the analytical technique. The aim of this work was to develop a method so as to allow the quantitative determination of CPEFA and also CPAFA where both are present in important natural seed oil. This method involves a series of reactions using a homogeneous transition metal complex, bromotris(triphenylphosphine)rhodium(l). This developed method involves the following reactions. a) Analysis one; Direct analysis of methyl esters. b) Analysis two; Hydrogenation of methyl esters. During this reaction, the unstable CPEFA are hydrogenated to their stable CPAFA analogues, thus allowing subsequent GLC analysis. The difference between the quantitative results (for the CPAFA content with other components of similar retention volume) obtained from the direct GLC analysis of methyl esters (analysis one) and the hydrogenated sample allows the determination of CPEFA content of the sample. N.B. The CPEFA content obtained by direct GLC analysis of methyl esters (analysis one) is unreliable owing to the instability of CPEFA on the GLC column. c) Analysis three; CPEFA destroyed using the catalyst. d) Analysis four; CPEFA destroyed using excess catalyst followed by hydrogenation . Similarly, the differences between the quantitative results obtained from the above two reactions, allows the determination of CPAFA. Reactions (c) and (d) are necessary because unsaturated components of similar retention volume to CPAFA are present in the sample ego kapok. The latter part of the study was concerned with identification of reaction products formed during analysis three. Complete degradation of CPEFA by the catalyst was achieved within five minutes using ethanol/toluene solvent system. Numerous compounds were isolated using preparative TLC and structure elucidation was carried out using NMR and MS.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Chemical engineering