“…Heterogeneous catalysts can be used optimally if they have high stability, strong active groups, large pores, large hydrophobic surface area, good recycling capability, and economical. Besides, factors affecting biodiesel production such as temperature, pressure, reactant molar ratio, methanol vapor feed rate, the active surface area of methanol vapor bubbles, and contact time or residence time of methanol vapor in oil [16]. Table 3 shows the composition of biodiesel as a result of reaction with catalyst fused fly ash.…”