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Sr–Mg Mixed Oxides as Biodiesel Production Catalysts
Author(s) -
Faungnawakij Kajornsak,
Yoosuk Boonyawan,
Namuangruk Supawadee,
Krasae Pawnprapa,
Viriyaempikul Nawin,
Puttasawat Buppa
Publication year - 2012
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201100346
Subject(s) - catalysis , transesterification , methanol , biodiesel , biodiesel production , adsorption , chemistry , desorption , sorption , inorganic chemistry , heterogeneous catalysis , nuclear chemistry , organic chemistry
The Sr–Mg basic catalysts were developed for biodiesel production through transesterification of palm oil with methanol. The evidence for synergistic effects between active Sr and Mg species was clearly demonstrated by transesterification tests over a series of Sr–Mg catalysts with varied Sr‐to‐Mg molar ratios. The catalyst properties were characterised by means of temperature‐programmed desorption of CO 2 (CO 2 ‐TPD), N 2 sorption, XRD, SEM and TEM experiments. The super strong basic site was formed in Sr–Mg catalysts through a partial solid state reaction induced by thermal treatment at 600 °C. The new basic site, together with the original basic site from SrO (average basic site density=757 μmol m −2 ), effectively catalysed a transesterification reaction at mild conditions. Biodiesel containing 96 % methyl esters was obtained at reaction conditions of 75 min, 60 °C, 0.1 M Pa, 3 wt. % catalyst loading and a methanol‐to‐oil ratio of 6:1, and the catalyst exhibited good reusability. Improved surface areas and porosities were also achieved compared to the unsupported SrO. Density functional theory (DFT) calculations of methylpropanoate adsorption on SrO, MgO and Sr/MgO showed that the adsorption energies of all adsorbate–surface complexes corresponded well with the experimental catalytic activity, which increased in the order MgO