Green and Facile Synthesis of Metal-Organic Framework Cu-BTC-Supported Sn (II)-Substituted Keggin Heteropoly Composites as an Esterification Nanocatalyst for Biodiesel Production
Qiuyun Zhang, Dan Ling, Dandan Lei, Jialu Wang, Xiaofang Liu, Yutao Zhang, Peihua Ma
Abstract
In the present study, metal-organic framework Cu-BTC supported Sn (II)-substituted Keggin heteropoly nanocomposite (Sn1.5PW/Cu-BTC) was successfully prepared by simple impregnation method and applied as a novel nanocatalyst for producing biodiesel from oleic acid (OA) through esterification. The nanocatalyst was characterized by Fourier transform infrared spectrometer (FTIR), wide-angle X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), nitrogen adsorption-desorption, thermogravimetric (TG), and NH3-temperature-programmed desorption (NH3-TPD). Accordingly, the synthesized nanocatalyst with a Sn1.5PW / Cu-BTC weight ratio of 1 exhibited the relatively large specific surface area, appropriate pore size, and high acidity. Moreover, the OA conversion of 87.7% was achieved under optimum reaction conditions. The nanocatalyst was reused seven times, and the OA conversion maintained more than 80% after three times. Kinetic study showed that the esterification reaction followed first-order kinetics and the activation energy (Ea) was calculated to be 38.3 kJ/mol.