The application of Zr incorporated Zn-Al dehydrated hydrotalcites as solid base in transesterification

• Zr-Zn-Al dehydrated hydrotalcites has high activity in the synthesis of biodiesel.
• No deactivation happens on the catalyst in the reaction of about 300 h.
• Incorporating Zr increases the basicity of the Zn-Al dehydrated hydrotalcites.
• Incorporating Zr enlarges the pore diameter of the Zn-Al dehydrated hydrotalcites.

Zr incorporated Zn-Al dehydrated hydrotalcites solid bases were obtained by calcining Zr-Zn-Al hydrotalcites at 140 °C and 200 °C. These solid bases were characterized by X-ray diffraction, N2 adsorption/desorption, UV–vis diffuse reflectance spectra, temperature programmed desorption of CO2 and infrared spectroscopy of CO2 adsorption. The results show that the Zr incorporated Zn-Al dehydrated hydrotalcites have larger pore diameter and stronger base-strength than the un-incorporated one. The sample with the Zr/Zn/Al ratio of 0.25/2.56/1 has the largest pore diameter, which is 10.6 nm. The basic sites of these solid bases are OH groups and the sample treated at 200 °C has more basic sites than which treated at 140 °C. These solid bases were evaluated as catalysts in the transesterification reaction for the biodiesel (FAME) production. The sample (with Zr/Zn/Al of 0.25/2.56/1) treated at 200 °C gives the FAME yield of 91.71% at 140 °C, 1.7 MPa and 1.0 h−1. It shows no deactivation in the reaction of about 300 h.

The Zr incorporated Zn-Al dehydrated hydrotalcites shows well activity and stability in the production of FAME by transesterification at a mild condition.Figure optionsDownload high-quality image (91 K)Download as PowerPoint slide