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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. |
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