Synthesis, Characterization, and Catalytic Ability Evaluation of MgO-γ-Al₂O₃/TiO₂-SO₄^2- for Transesterification of Waste Cooking Oil by Methanol

The catalytic system MgO-γ-Al₂O₃/TiO₂-SO₄^2- was synthesized, and then characterized by XRD, IR, NH3-TPD, CO2-TPD, BET, EDX methods. As can be seen from the results of physical characterization, the synthesized MgO-γ-Al₂O₃/TiO₂-SO₄^2- material owns a large surface area of 261.85 m²/g, a mean capillary diameter of 95.5 Å. The presence of TiO₂ and SO₄^2- creates strong acid sites on the catalyst surface, as indicated by the NH3 desorption temperature peak at 509.5°C and 546.6°C. The presence MgO phase creates strong basic sites, as specified by the CO2 desorption temperature peak at 502.1°C. A transesterification between methanol and waste cooking oil (the volume ratio of methanol to oil of 1: 1) using MgO-γ-Al₂O₃/TiO₂-SO₄^2--as a catalyst was carried out at 120°C for 4 hours. The reaction efficiency was about 98.1%.