TY - JOUR
T1 - Influence of pH on noble metal catalysed alcohol oxidation: reaction kinetics and modelling
AU - Gangwal, V.R.
AU - Schaaf, van der, J.
AU - Kuster, B.F.M.
AU - Schouten, J.C.
PY - 2005
Y1 - 2005
N2 - The Pt-catalysed oxidation of the alcohol methyl a-D-glucopyranoside to 1-O-methyl a-D-glucuronic acid has been studied under varying pH conditions. Two types of catalysts with different metal dispersion are used, that is, Pt on active carbon support and Pt on graphite support. The pH of the reaction medium is varied between 6 and 10. The initial reaction rate increases with an increase in pH, and so does the rate of catalyst deactivation, because of overoxidation, for both catalysts. The carbon-supported Pt catalyst gives higher initial reaction rates compared with the graphite-supported Pt catalyst.
A dynamic, pH-dependent, electrochemical kinetic model is presented based on a detailed investigation of the mechanism of alcohol oxidation. The model adequately describes the observed pH effect by considering the alcohol dehydrogenation occurring in two parallel reaction steps, one playing a role under acidic conditions, which is independent of the hydroxyl concentration, and a second one playing a role under alkaline conditions, which is linearly dependent on the hydroxyl concentration.
AB - The Pt-catalysed oxidation of the alcohol methyl a-D-glucopyranoside to 1-O-methyl a-D-glucuronic acid has been studied under varying pH conditions. Two types of catalysts with different metal dispersion are used, that is, Pt on active carbon support and Pt on graphite support. The pH of the reaction medium is varied between 6 and 10. The initial reaction rate increases with an increase in pH, and so does the rate of catalyst deactivation, because of overoxidation, for both catalysts. The carbon-supported Pt catalyst gives higher initial reaction rates compared with the graphite-supported Pt catalyst.
A dynamic, pH-dependent, electrochemical kinetic model is presented based on a detailed investigation of the mechanism of alcohol oxidation. The model adequately describes the observed pH effect by considering the alcohol dehydrogenation occurring in two parallel reaction steps, one playing a role under acidic conditions, which is independent of the hydroxyl concentration, and a second one playing a role under alkaline conditions, which is linearly dependent on the hydroxyl concentration.
U2 - 10.1016/j.jcat.2004.11.021
DO - 10.1016/j.jcat.2004.11.021
M3 - Article
SN - 0021-9517
VL - 229
SP - 389
EP - 403
JO - Journal of Catalysis
JF - Journal of Catalysis
IS - 2
ER -