Enhanced stability of t-butanol reaction intermediates on oxygen covered Cu(110): Cleavage of unactivated CH bonds on metal surfaces

The adsorption and reaction of t-butanol on clean and oxygen predosed Cu(110) was studied in order to assess the stability of t-BuO_(a) which lacks a β-hydride elimination decomposition pathway. On the clean surface the alcohol adsorbs and desorbs intact without further reaction due to steric hindrance, in contrast to the reactions of ethanol, n-proponal, i-propanol and n-butanol, which readily form their respective alkoxides. On the oxygen predosed surface the alcohol reacts to form the surface t-butoxide, which further dehydrogenates at 600 K to yield isobutylene and water. In contrast to the reaction of t-butanol on oxygen predosed Ag(110), no isobutylene oxide or acetone is formed. The temperature at which CH bond cleavage in t-butoxide occurs on Cu(110) indicates a substantial stabilization of the tertiary alkoxide compared to the primary and secondary alkoxides studied previously. This difference is attributed to the presence of activated CH bonds in the more reactive alkoxides and is consistent with their relative reactivity in organometallic complexes.