文献类型：期刊文献

英文题名：On the Alkalinity of Solid Catalysts for Transesterification of Dimethyl Carbonate and Ethanol

作者：Zhang, Tianyu[1];Wu, Shun[2];Shen, Weihua[1];Fang, Yunjin[1]

机构：[1]East China Univ Sci & Technol, Sch Chem Engn, State Key Lab Chem Engn, Shanghai 200237, Peoples R China;[2]Zhejiang Univ, ZJU Hangzhou Global Sci & Technol Innovat Ctr, Hangzhou 310058, Peoples R China

年份：2025

卷号：15

期号：13

外文期刊名：APPLIED SCIENCES-BASEL

收录：;EI(收录号：20252918778839);WOS:【SCI-EXPANDED(收录号:WOS:001526161300001)】；

基金：This research was funded by the National Natural Science Foundation of China (Project No. 21576083) and supported by the Shaanxi Coal Industry Joint Fund Project (No. 2019JLM-20).

语种：英文

外文关键词：alkalinity; transesterification; ethanol; dimethyl carbonate; solid catalyst

摘要：In this study, Mg-Al-Zn, MgO, Al2O3, and ZnO were synthesized via the co-precipitation method and evaluated as catalysts for the transesterification reaction of dimethyl carbonate (DMC) and ethanol. The crystal structure, morphological characteristics, pore structure properties, and alkaline properties of the catalysts were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, temperature-programmed desorption of CO2 (CO2-TPD), and Fourier transform infrared spectroscopy (FTIR). The surface alkali strength and alkalinity of the solids were determined using the Hammett indicator method and non-aqueous titration. When Al2O3 and ZnO are used as catalysts for this transesterification, the conversion rate of dimethyl carbonate is relatively low. When MgO and Mg-Al-Zn are used as catalysts, the conversion rate of dimethyl carbonate is higher. This indicates that the alkali strength of the catalyst for the transesterification reaction needs to be greater than 9.3. Additionally, the activity of the catalysts is also related to the amount of the alkaline sites on the solid surface. The alkali strength of MgO is greater than 11; its excessively high alkali strength will react with CO2 and H2O during use, resulting in a reduction in the number of alkaline sites and thus showing unsatisfactory reactivity. The alkaline strength of the Mg-Al-Zn catalyst ranges from 9.3 to 11.0. When used for the first time, the number of alkaline sites decreases, and then the alkalinity remains at a certain value. Therefore, the alkaline strength of the solid catalyst for the transesterification reaction between DMC and ethanol needs to be between 9.3 and 11.0 so that the number of alkaline sites on the catalyst surface remains unchanged and the catalytic activity remains stable.