The development of low-alcohol Baijiu is consistent with demand for the industry’s sustainable development. However, the ester aroma of low-alcohol Baijiu is insipid and unstable—mainly due to the hydrolysis of esters during shelf life—thus reducing the industry scale of low-alcohol Baijiu to a significantly small range. An electrochemical method for improving low-alcohol Baijiu’s ester concentration and stability was investigated from the aspects of thermodynamics and kinetics. The key finding is that the new Baijiu’s ester content obtained through distillation is relatively high, exceeding its content in the thermodynamic equilibrium state. Thus, the ester will be hydrolyzed during shelf life. The idea of applying electrochemical catalytic esterification technology to the production of low-alcohol Baijiu in this study is directly derived from the production practice of Baijiu factories; it provides a direction for the further optimization of low-alcohol Baijiu to facilitate the production of an alternative product that will contribute to public health.Keywords:electrochemical esterification;low alcohol liquor;Baijiu;ester aroma
The development of low-alcohol liquor (Baijiu) can represent a tool to solve the problems of excessive alcohol intake. However, low-alcohol liquor has an insufficient ester aroma and a bland taste due to the alcohol dilution process. This study proposes an electrochemical catalysis technology to catalyze the esterification reaction between the acid and alcohol in liquor, thereby enhancing the ester aroma of low-alcohol liquor. In the electrochemical conversion process, the gold electrode with a certain potential promotes the formation of carbocation intermediate from corresponding carboxylic acid, thereby improving the esterification reaction efficiency. The key finding is that the total ester content of liquor treated using this technology is increased by more than 20%, and a strong ester aroma is attained. This study clarifies the electrocatalytic mechanism of the esterification reaction in liquor, and provides a new idea for making low-alcohol liquor become more attractive for aroma and taste aspects trying to obtain an alternative product contributing to the public health.
Ideal laminar membrane reactors (LMR) necessitate the rational construction of 2D nanoconfined channels and regulation of microenvironment. The intrinsic structure-activity relationship of laminar membrane reactors essentially remains unclear. Herein, amorphous/crystalline HTiNbO 5-X nanosheets (NS) with abundant oxygen vacancy (V O ) are successfully prepared and stacked as 2D sub-nanoconfined membrane flow reactors with different interlayer spacings. When the interlayer spacing is decreased to 11.0 Å, the representative HTiNbO 5-X membrane exhibits impressive conversion of ≈ 100% within 26.6 s and turnover number of up to 306.42 for the esterification of benzyl alcohol at 23 °C. The combination of structural characterizations and theoretical calculations reveals that the synergistic effect of V O and sub-nanoscale confinement greatly promotes the adsorption and orbital symmetry matching of reactants, and reduces the overall energy barrier. Furthermore, the HTiNbO 5-X LMR is accessible for other alcohol derivatives, indicating the efficient and green synthesis of acetate ester flavours under mild conditions. This work demonstrates the promising potential of the metal oxide nanosheets to create inorganic laminar membrane reactors for continuous organic synthesis.
危险品化学品经营许可证（带存储）