Kinetic modeling on oxidation of arabinose to arabinonic acid in base-free medium over synergistic PtCu/TiO2 catalyst

Arabinonic acid (AA) is an essential building block for the food and pharmaceutical industries. However, green and atomically efficient synthesis of AA remains a grand challenge, as most previous reports have been focused on the alkaline-promoted oxidation of arabinose. In this work, we firstly reported lumped kinetic modeling of the oxidation of arabinose to AA in base-free medium, with detailed reaction networks involved in the C-H and C-C cleavage reactions. It is found that the bimetallic PtCu/TiO2 catalyst displays strong synergism due to electronic coupling at metal-support interface, leading to an almost two-fold enhancement in catalytic activity in comparison with monometallic Pt/TiO2 catalyst. According to detailed analysis on reaction network and kinetic modeling, the presence of Cu mainly contributes to formulating additional active sites for the oxidation and C-C cleavage reactions. The quantitative assessment for conversion of arabinose could provide useful information for modeling and process development for various other important sugars.