Showing papers by "Atsushi Takahashi published in 2022"

Process design for efficient production from glycerol into high-value chemicals

Abstract: 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.

Proposal of complete utilization system of soapstock by electrolysis

Abstract: In deacidification during vegetable oil refinery, a large amount of soapstock, mainly sodium salt of fatty acid, are generated and wasted. We propose an innovative system for the complete utilization of soapstock by Kolbe electrolysis. In conventional Kolbe electrolysis, only water-soluble carboxylic acid with short alkyl chain such as acetic acid and butyric acid are decarboxylated and dimerized to produce hydrocarbons such as ethane and butane. Although fatty acid salts have long alkyl chains, they are soluble in water, and Kolbe electrolysis can be applied to them. Soapstock will be converted by electrolysis into long-chain hydrocarbons used as biofuels and, sodium hydroxide used in vegetable oil refinery. As a result of applying Kolbe electrolysis to an aqueous solution of caprylic acid sodium salt, the formation of hydrocarbons, tetradecane, and sodium hydroxide was observed. When the generated hydrocarbons were used for power generation, the generated energy was almost the same as the energy input in the electrolysis. This means that the soap stock can be reused without any external energy input. Therefore, it is suggested that this electrolysis system will be both carbon-negative and profitability.