The kinetics of the thermal decarboxylation of a series of substituted sodium phenylpropiolates were studied in detail. The reaction proceeded without formation of significant amounts of side products: its rate was independent of hydrogen ion concentration. The relative rates of decarboxylation are in the order: p-NO2 > m-NO2> m-CF3 > m-Cl > p-Cl > H > m-CH3, and the entropies of activation are large and positive. The results were discussed in terms of the unimolecular (SE1) mechanism. A quantitative study of effects of substituents on the decarboxylation rates was made by the application of the Hammett free energy relationship. The e value of the Hammett plot was 0.886 +/- 0.013. Deviation of para substituted compounds from the Hammett relationship were discussed in terms of para interaction or conjugation effects in the initial or the transition states. / Thesis / Master of Science (MS)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/23592 |
| Date | 09 1900 |
| Creators | Wong, Edward |
| Contributors | Bourne, A. N., Chemistry |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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