Effect of fluorination on thiol reactivities. Reaction of 2,2,2-trifluoroethanethiol on Mo(110)
- Harvard Univ., Cambridge, MA (United States)
The reactions of 2,2,2-trifluoroethanethiol on Mo(110) were studied using temperature-programmed reaction, Auger electron, and infrared spectroscopies. Most significant is the evolution at 265 K of trifluoroethyl radical from a saturation coverage of CF{sub 3}CH{sub 2}S-. The strong coverage dependence for trifluoroethyl radical evolution and models depicting trifluoroethyl thiolate orientation at saturation coverage strongly suggest that surface crowding plays a significant role in radical formation. The stability of the radical and the steric inhibition to finding an adsorption site explain the evolution of the radical into the gas phase. C-S bond hydrogenolysis, yielding trifluoroethane, and defluorination, yielding difluoroethylene, are of nearly equal importance in the reaction of trifluoroethyl thiolate, whereas C-S bond hydrogenolysis of ethyl thiolate to form ethane predominates. The C-S bond hydrogenolysis pathway is similar for the two thiols, occurring at approximately 300 K in both cases. Dehydrogenation and alkene elimination from CH{sub 3}CH{sub 2}S- occur at approximately 340 K, as the supply of surface hydrogen is depleted through hydrogen recombination. In contrast, defluorination and fluoroalkene elimination from CF{sub 3}CH{sub 2}S- occur over a wide temperature range, 200-520 K. 41 refs., 6 figs., 2 tabs.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG02-84ER13289
- OSTI ID:
- 62455
- Journal Information:
- Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 21 Vol. 99; ISSN JPCHAX; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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