Mg–Al Mixed Oxide Derived from Hydrotalcites Prepared Using the Solvent-Free Method: A Stable Acid–Base Bifunctional Catalyst for Continuous-Flow Transesterification of Dimethyl Carbonate and Ethanol

• Published in: Industrial & engineering chemistry research 2020-04, Vol.59 (13), p.5591-5600
• Main Authors: Wang, Hefang, Liu, Wenrui, Wang, Yiyan, Tao, Ning, Cai, Huanhuan, Liu, Jidong, Lv, Jianhua
• Format: Article
• Language: English
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.9b06303

Mg–Al oxides were prepared by facile solvent-free grinding of Mg–Al layered double hydroxide and were used as catalysts for continuous-flow transesterification of dimethyl carbonate and ethanol. The surface and structure properties of the prepared Mg–Al oxides were characterized by X-ray powder diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectra, and N2 adsorption–desorption. Moreover, the acid–base properties of the prepared catalysts were characterized using NH3-TPD, CO2-TPD, and pyridine-IR. The Mg–Al oxides prepared using the solvent-free method with a molar ratio of 2.0 (CHT-2-SF) exhibit good catalytic performance, which has medium basic sites, weak acidic sites, and high Brunauer–Emmett–Teller surface areas. A correlation between basicity–acidity and catalytic activity demonstrates that the conversion of ethanol increases with increasing medium basicity and weak acidity of the catalyst. The activity of CHT-2-SF remained almost unchanged after 1800 h on stream.