Eletrooxidações de acetaldeído comum e etanol isotopicamente marcado (H3 13C-12CH2OH) em superfície de platina policristalina acompanhadas por FTIRS in situ

Abstract

This is work treat of the acetaldehyde and labeled ethanol oxidations, both kinds in percloric acidic medium, 0,1 Mol L-1 HClO4 on the Pt polycrystalline surface with used conventional electrochemical and spectroscopy techniques (FTIRS in situ). From acetaldehyde, wanted to find the mean concentration that better favor the reaction to evolve for CO2 in the potential smaller from production of the kind. The concentration 0,01 Mol L-1 was better suitable, but the increase of the concentration in solution, this is pathway was whole inhibited. However, in the high potential the form to acetic acidic is favorable. For main cronoamperometry, acetaldehyde in the concentration 0,02 Mol L-1, were able proof results in situ FTIRS. According to potential, this is results was interpreted second pattern to consider: the pear adsorbed kinds (Langmuir-Hinshelwood) and other where consider only one adsorbed kinds between adsorbed (pattern Eley-Rideal mechanism). In the case of ethanol labeled oxidation (H3 13CO 12CH2OH), it is search to look into the path delineated from way severous of the reaction from to form CO2. The results showed that is product would to be results of the intermediates oxidations contained carbon from alcohol group and intermediates contained carbon from group methyl; however, the intermediates contained carbon alcohol group is mores able reactive in the zone potential searched in the work, is this mores, confronted with able reactive metil group. The path double that yield CO2 in the zone potential below 1,0 V, are yielded coupling bands 12COL and 13COL which coexist in below potential. In the presence kind 13COL in 0,4 V potential proof that of the efficiency of the platinum electrode for the oxygenation group metil in the zone below potential. In the potential largest that 1,0 V, where exist the formation continuous of carbon dioxide, the difference in the greatness bands associated from 12CO2 e 13CO2 (double path product contained carbon), was interpreted in the sense of the electrochemical conditions infortunable for remover hydrogen group metil; additional this is kind was to promote for yield from molecules, which not is able identify for whole technique.