Preparation and catalytic performance in esterification of a bamboo-based heterogeneous acid catalyst with microwave assistance

With the assistance of microwave, a novel bamboo-based heterogeneous acid catalyst is prepared by partial carbonization followed by sulfonation and utilized in esterification of oleic acid with methanol for biodiesel production. The catalyst is further characterized by elemental analysis, acid-base titration, FT-IR, XRD, SEM and nitrogen adsorption-desorption analysis to reveal its physical and chemical properties. After carbonization at 350 °C for 2 h and sulfonation at 105 °C for 10 min, the thus prepared catalyst possesses amorphous carbon structure with sulfonic group density of 1.80 mmol/g. The catalyst supplies esterification conversion efficiency of 97.31% with the esterification temperature of 65 °C, esterification duration of 1 h, catalyst loaded percentage of 5 wt% and molar ratio of methanol to oleic acid of 8. Microwave effectively shortens the required durations of both sulfonation and esterification. In addition, the bamboo derived heterogeneous acid catalyst gains satisfying regenerability and efficiency of 96.22% is restored after 5 cycles.