The phase transitions of some orientationally-disordered solids (plastic crystals) have been studied by DSC, and variable-temperature-IR and -Raman spectroscopy. The adamantane derivatives, 1-bromoadamantane (1-C$ sb{10}$H$ sb{15}$Br) and 2-chloroadamantane (2-C$ sb{10}$H$ sb{15}$Cl) were found to have two phase transitions, at 283 K and 312 K for the former and 227 K and 242 K for the latter; 2-bromoadamantane (2-C$ sb{10}$H$ sb{15}$Br) and 1-chloroadamantane (1-C$ sb{10}$H$ sb{15}$Cl) only exhibited one phase transition each, at 281 K and 245 K, respectively. Only one phase transition was found for 9-bicyclononanone (9-C$ sb9$H$ sb{14}$O) at 299 K. Oxanorbornane (C$ sb6$H$ sb{10}$O), a liquid, was found to have three phase transformations (192, 234, and 245 K), with the 234 K transition being metastable. Another phase transition, which is both time dependent and rate-of-cooling dependent, was found for o-carborane (o-C$ sb2$B$ sb{10}$H$ sb{12}$) by variable-temperature infrared spectroscopy. The infrared and Raman spectra of the adamantane derivative, 2-adamantanone (2-C$ sb{10}$H$ sb{14}$O), revealed that a new low-temperature phase was present after cycling. / Micro-Raman pressure spectroscopy was used for the first time in the study of phase transitions of plastic crystals. The same phase transformation of 1-chloroadamantane that occurred at 245 K and 1.01 bar was found to occur at 295 K and $ sim$5 kbar. The o-carborane phase transition which took place at 274 K and 1.01 bar also takes place at 295 K and $ sim$10 kbar. Finally, 2-chloroadamantane, which exhibited two phase transitions (227 K and 242 K) at atmospheric pressure, also underwent phase transformations at room temperature and 3 and 11 kbar, respectively.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.75971 |
| Date | January 1988 |
| Creators | Paroli, Ralph Michaël |
| 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: 000909972, proquestno: AAINL52497, Theses scanned by UMI/ProQuest. |
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