Comparison of the reactions of branched alcohols and aldehydes on Rh(111)
- Univ. of Delaware, Newark, DE (United States)
Alcohols adsorbed on the Rh(111) surface have been suggested to decompose via unstable surface oxametallacycle intermediates rather than via aldehydes. The chemistry of alcohols and aldehydes containing multiple methyl groups at the {Beta}-position was examined in this study to determine whether metallacycle formation could be blocked. Temperature-programmed desorption (TPD) and high resolution electron energy loss spectroscopy (HREELS) studies demonstrated that complete substitution of {Beta}-hydrogens with methyl groups did lead to common alcohol and aldehyde decomposition pathways. 2,2-Dimethyl-1-propanol and 2,2-dimethyl-1-propanal decarbonylated to deposit isobutene on the surface; the sequence of subsequent dehydrogenation steps was the same, whether adsorbed isobutene was generated from these oxygenates, from t-butanol, or by isobutene exposure. In contrast, partial substitution at the {Beta}-position did not produce a common path for alcohol and aldehyde decarbonylation. 2-Methyl-1-propanol decomposition resulted in fragmentation of the hydrocarbon backbone of the molecule, generating C{sub 1} and C{sub 2} fragments from the reaction of the oxametallacycle intermediate. 2-Methyl-1-propanal, however, decarbonylated cleanly to form surface propylidyne intermediates, analogous to the chemistry observed for other aldehydes on Rh(111). 24 refs., 15 figs., 5 tabs.
- DOE Contract Number:
- FG02-84ER13290
- OSTI ID:
- 219691
- Journal Information:
- Journal of Physical Chemistry, Vol. 100, Issue 6; Other Information: PBD: 8 Feb 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Chemistry of oxygenates on transition metal surfaces: Activation of C- H, C-C, and C-O bonds. Progress report, December 15, 1991
Chemistry of oxygenates on transition metal surfaces: Activation of C- H, C-C, and C-O bonds