H3PMo12O40/Agroindustry waste activated carbon-catalyzed esterification of lauric acid with methanol: a renewable catalytic support

Abstract

The heterogeneous catalytic route to produce biodiesel can reduce the amount of effluents generated in the steps of esters purification and allows the reuse of catalysts. Specially, when the catalytic supports are synthesized from biomass wastes the process become even more environmentally friendly. In this work, we have synthesized activate carbons (ACs) from agroindustry waste generated after the extraction of essential oil of Candeia wood residue. These ACs were used to support H3PMo12O40. The performances of all the supported catalysts were evaluated on the lauric acid esterification reactions with methanol. The catalysts were produced through impregnation method, varying the H3PMo12O40 load and the support nature (i.e. commercial AC or produced from agroindustry residue). All materials were characterized by thermal analysis, FT-IR spectroscopy, SEM, EDS, BET surface area and powder X-ray diffraction. The catalysts showed good thermal stability. Data of the X-ray diffraction indicated that regardless support origin, a high dispersion of H3PMo12O40 was achieved. High turnover numbers were achieved by the H3PMo12O40/AC catalysts; 7205 for 10 wt% H3PMo12O40/commercial AC and 3571 for 10 wt% H3PMo12O40/agroindustry waste AC. Tests of reuse and leaching of the catalysts were also carried out. A strong deactivation of the catalyst was observed when it was reused directly, without previous treatment.