ALTERATION OF PRIMARY ALCOHOL REACTION PATHWAYS ON RH(111) - FLUORINATION BLOCKS OXAMETALLACYCLE FORMATION

Temperature programmed desorption (TPD) and high-resolution electron e nergy loss spectroscopy (HREELS) studies of 2,2,2-trifluoroethanol on Rh(111) were performed in order to determine if the oxametallacycle-me diated pathway for ethanol decarbonylation could be circumvented by re placement of H with F at the beta-carbon. Reaction of 2,2,2-trifluoroe thanol produced trifluoroacetyl fluoride, CO, HF, and H-2. Trifluoroac etaldehyde could also be desorbed as a product of trifluoroethanol dec omposition under certain conditions; the observation of this product a nd of trifluoroacetyl fluoride indicates that aldehyde and acyl interm ediates, rather than metallacycles, are formed in the course of this r eaction. These results demonstrate that oxametallacycle formation from alcohols on Rh(111) can be blocked by complete substitution at the be ta-carbon.