A kinetic study on the thermal decomposition of 2,2-dichloro-3-(9-fluorenyl) episulfide (28) was investigated in detail. Solid evidence as to the nature of the desulfurization process is given. A two-term rate equation is derived to account for the overall rate changes. Both a unimolecular and bimolecular ionic mechanism involving the concatenation of sulfur atoms was proposed to account for the observed kinetic behaviour. An extended study in 15 different solvents at different temperatures showed the desulfurization is ionic in nature. Activation parameters were calculated and rationalized with respect to differences in solvation of the ground and transition states. A linear isokinetic relationship was found indicating a similar mechanism of decomposition in these solvents. Rates of reaction were also found to be linearly correlated with dielectric constant as well as the $ pi sp *$ scale of Kamlet and Taft. A solvent isotope effect was found to exist and the rate of desulfurization is decreased in the presence of acetic acid. A radical mechanism is discounted from a rate study in the presence of radical inhibitors. / Several new disubstituted 9-fluorenones were prepared for the first time using Meyers methodology. These and other mono and disubstituted fluorenones were employed in an effort to synthesize a variety of novel stable thiiranes. Only three thiiranes were prepared in this manner. The X-ray crystal structures of 2,2-dichloro-3,3-diphenyl episulfide (110) and 2,2-dichloro-3-dibenzosuberonyl episulfide (123) were also obtained for the first time. / Thiirane 28 as well as sodium cyanodithioformate (139) were investigated as possible precursors to diatomic sulfur but no evidence of this interesting intermediate was detected. The chlorination of tetramethylthiuram disulfide, however, in the presence of 1,3-dienes, afforded products consistent with the trapping of diatomic sulfur. (Abstract shortened by UMI.) ftn*Please refer to the dissertation for diagram.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.39531 |
| Date | January 1992 |
| Creators | Chew, Warren |
| Contributors | Harpp, David N. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001327403, proquestno: NN87642, Theses scanned by UMI/ProQuest. |
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