Glycerol can be effectively converted to glyceric acid, a high value‐added pharmaceutical raw material, through its partial oxidation over an Au/Al2O3 catalyst under strongly basic conditions. The factors important for the highly selective production of glyceric acid were investigated experimentally. It was clarified that NaOH was involved in the glycerol activation step to a glycerol alkoxide intermediate (2, 3‐dihydroxypropoxide) in the liquid phase, then glyceric acid was formed by OOH species derived from O2 on an Au catalyst in the partial oxidation step. We have newly discovered the concerted effect of NaOH and O2 in different reaction steps.

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There is an urgent need to develop effective methods to use glycerol, a by-product of biodiesel production, by converting it into high-value chemicals. The by-product glycerol is contaminated with strong alkaline as a catalyst, and the environmental loads of the purification process to remove the contaminants has been a bottleneck to its utilization. As one way to solve this problem, it has been reported that glycerol can be converted to glyceric acid (GA), which is used as a pharmaceutical raw material, by partial oxidation of glycerol using an Au catalyst under alkaline condition. However, the GA yield is low because many side reactions proceed simultaneously. To construct a practical process for efficient GA production, it is necessary to both experimentally analyze the reaction mechanism and to develop a kinetic model that can quantitatively predict the reaction behavior under a wide range of conditions.The purpose of this study is to establish a methodology for process design of efficient production of GA from the by-product glycerol. In our previous study, the reaction mechanism including alkaline and the reactive oxygen species OOH, which is formed from O2 and H2O on Au catalyst, in GA formation was clarified and a kinetic model taken it into account was constructed. In present study, the model was additionally taken temperature dependency into account and enabled to predict GA yield in wide range of operating conditions. In order to design the catalysts, the relationship between GA yield and coverages of adsorbed species on active sites was investigated by the model simulation and it was revealed that the affinity between support and H2O greatly affects GA yield, suggesting that the support, which has strong interaction with H2O, increases the GA yield.

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