Biodiesel production process by homogeneous/heterogeneous catalytic system using an acid–base catalyst

The transesterification of triglycerides contained in waste oilseed fruits with methanol has been studied in heterogeneous/homogeneous systems using acid and base catalysts. The acid catalysts (strong acid catalysts: USY, BEA, FAU-X, and weak acid catalysts: MCM-41 and ITQ-6 with Si/Al = ∞) were prepared by hydrothermal synthesis procedures. In order to obtain acid–base catalysts, potassium was loaded on different materials by ionic exchange (obtaining K-MCM-41, K-ITQ-6,). XRD, ICP-MS, IR after CO and CO2 adsorption, thermal analyses and N2 adsorption/desorption techniques have been used for catalysts characterization. The highest triglycerides conversion and biodiesel yield values were achieved by K-ITQ-6 catalysts, after 24 h of reaction at 180 °C. Deactivation of this catalyst occurs for potassium leaching, but its regeneration and reuse are feasible and easy to perform. A possible continuous biodiesel production process has been proposed.

Graphical abstractThe transesterification of triglycerides contained in waste oilseed fruits with methanol has been studied in heterogeneous/homogeneous systems using acid and base catalysts (strong acid catalysts: USY, BEA, FAU-X, weak acid catalysts: MCM-41 and ITQ-6, and acid–base catalysts: K-MCM-41, K-ITQ-6). The highest catalytic performances were achieved by K-ITQ-6 catalysts, after 24 h of reaction at 180 °C. A possible continuous biodiesel production process has been proposed. The figure shows triglycerides conversion, biodiesel yield and FFAs conversion, as function of time, obtained using K-ITQ-6 catalyst at 180 °C, at 5 wt% respect to the oil and 1:20 molar ratio between oil:methanol.Figure optionsDownload full-size imageDownload high-quality image (80 K)Download as PowerPoint slide