On the Alkalinity of Solid Catalysts for Transesterification of Dimethyl Carbonate and Ethanol
In this study, Mg-Al-Zn, MgO, Al<sub>2</sub>O<sub>3,</sub> 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, p...
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2025-06-01
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| author | Tianyu Zhang Shun Wu Weihua Shen Yunjin Fang |
| author_facet | Tianyu Zhang Shun Wu Weihua Shen Yunjin Fang |
| author_sort | Tianyu Zhang |
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| description | In this study, Mg-Al-Zn, MgO, Al<sub>2</sub>O<sub>3,</sub> 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 CO<sub>2</sub> (CO<sub>2</sub>-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 Al<sub>2</sub>O<sub>3</sub> 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 CO<sub>2</sub> and H<sub>2</sub>O 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. |
| format | Article |
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| issn | 2076-3417 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | MDPI AG |
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| series | Applied Sciences |
| spelling | doaj-art-8fe93d1a1bc743a2bc8a86778f6b43982025-07-11T14:36:05ZengMDPI AGApplied Sciences2076-34172025-06-011513722510.3390/app15137225On the Alkalinity of Solid Catalysts for Transesterification of Dimethyl Carbonate and EthanolTianyu Zhang0Shun Wu1Weihua Shen2Yunjin Fang3State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, ChinaZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310058, ChinaState Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, ChinaState Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, ChinaIn this study, Mg-Al-Zn, MgO, Al<sub>2</sub>O<sub>3,</sub> 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 CO<sub>2</sub> (CO<sub>2</sub>-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 Al<sub>2</sub>O<sub>3</sub> 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 CO<sub>2</sub> and H<sub>2</sub>O 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.https://www.mdpi.com/2076-3417/15/13/7225alkalinitytransesterificationethanoldimethyl carbonatesolid catalyst |
| spellingShingle | Tianyu Zhang Shun Wu Weihua Shen Yunjin Fang On the Alkalinity of Solid Catalysts for Transesterification of Dimethyl Carbonate and Ethanol Applied Sciences alkalinity transesterification ethanol dimethyl carbonate solid catalyst |
| title | On the Alkalinity of Solid Catalysts for Transesterification of Dimethyl Carbonate and Ethanol |
| title_full | On the Alkalinity of Solid Catalysts for Transesterification of Dimethyl Carbonate and Ethanol |
| title_fullStr | On the Alkalinity of Solid Catalysts for Transesterification of Dimethyl Carbonate and Ethanol |
| title_full_unstemmed | On the Alkalinity of Solid Catalysts for Transesterification of Dimethyl Carbonate and Ethanol |
| title_short | On the Alkalinity of Solid Catalysts for Transesterification of Dimethyl Carbonate and Ethanol |
| title_sort | on the alkalinity of solid catalysts for transesterification of dimethyl carbonate and ethanol |
| topic | alkalinity transesterification ethanol dimethyl carbonate solid catalyst |
| url | https://www.mdpi.com/2076-3417/15/13/7225 |
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