Preparation of nano-CaO and catalyzing tri-component coupling transesterification to produce biodiesel

Abstract

Nano-CaO with different particle sizes and crystallinity was prepared by sol-gel method. A tri-component coupling transesterification of rapeseed oil/dimethyl carbonate (DMC)/methanol was used to determine the viability of prepared nano-CaO as a basic catalyst for biodiesel synthesis. Nano-CaO exhibits better catalytic performance than commercial CaO for biodiesel production under same reaction condition. At 1:1:8 molar ratio of oil to DMC to methanol, 5 wt% nano-CaO catalyst (calcined at 800 °C), and 65 °C reaction temperature, the reaction gave the best results, and the fatty acid methyl ester yield exceeded 92% at 4 h which was 2 h shorter than that of commercial CaO. The catalyst calcined under different temperature has been characterized by BET, CO₂-TPD, TGA, XRD, and SEM. As the results shows that nano-CaO calcined at 800 °C exhibited the most active which should be contributed to the presence of good dispersivity, large surface area and pore volume.

Graphical Abstract

An efficient transesterification reaction has been developed over nano-CaO which possessing good dispersivity, larger surface area and pore volume. Dimethyl carbonate as a green methylating reagent, has been added aiming to turn rapeseed oil to biodiesel with no glycerol by-product.

Keywords:

• Nano-CaO
• tri-component coupling transesterification
• biodiesel
• heterogeneous

Acknowlegement

We are thankful for the work of Modern Analysis and Testing Center of Xi'an Shiyou University.

Additional information

Funding

The work was supported financially by National Science Foundation of China (No. 21763030), Scientific Research Plan Projects of Shaanxi Science and Technology Department (2019GY-136) and Xi'an Science and Technology Project (201805038YD16CG22(3)).