Aluminosilicates with ordered hexagonal mesopores denoted as MAS-7 and MAS-9 with uniform size were synthesized from zeolite β assembly and ZSM-5 precursors, respectively, with P123 as a surfactant, via the cooperative self-assembly pathway. A series of 12 tungstophosphoric acid (TPA) supported on MAS-7 and MAS-9 (H 3 PW 12 O 40 /MAS-7/MAS-9) catalysts for biodiesel production were synthesized via the wet impregnation technique. The characterization of the supports and catalysts was done using N 2 adsorption–desorption analysis, X-ray diffraction (XRD), and pyridine adsorption Fourier transform infrared and Raman spectroscopies. Also, the 29 Si magic-angle spinning and cross-polarization/MAS nuclear magnetic resonance (NMR) techniques were employed to study MAS-7/MAS-9 and the supported solid acid catalyst surfaces. The nitrogen sorption analysis and XRD patterns indicated the formation of well-defined mesoporous materials, whereas IR spectroscopy confirmed the presence of four distinct types of OH groups with varying degrees of acidity. 29 Si MAS NMR signified a stronger interaction between the framework of mesoporous aluminosilicates and H 3 PW 12 O 40 . The X-ray absorption near-edge spectra of L 1 - and L 3 -edge tungsten showed that W in the H 3 PW 12 O 40 /MAS-9 sample exists as W 6+ , indicating the tungsten environment similar to that of H 2 WO 4 with O h symmetry. The catalytic activity of the synthesized catalysts was investigated for biodiesel synthesis using unrefined green seed canola oil as a feedstock, giving a methyl ester yield of 76.5–88.7 wt % under optimized reaction conditions. The catalyst activities were strongly correlated with the surface chemistry of the TPA-supported MAS-7 and MAS-9 catalysts.

12-Tungstophosphoric acid (TPA)-supported γ-Al 2 O 3 catalysts were synthesized with varying TPA loadings. Catalysts characteristics were determined using Brunauer-Emmett-Teller surface area analysis, thermogravimetric analyses, X-ray diffraction, Raman, pyridine-adsorbed Fourier-transform infrared spectroscopy, and 13 C hpdec (high-power 1 H decoupling) nuclear magnetic resonance, whereas surface morphology was studied using scanning electron microscope and transmission electron microscopy analyses. Surface defects were found in the catalyst with higher TPA loadings (55-65 wt.%). The presence of WO x was observed at higher loadings and later agglomerated into tungsten oxide crystals. The TPA impregnated catalysts were investigated for biodiesel synthesis from canola oil. The reaction was found to be independent of mass transfer limitation. The activation energy was 33.6 kJ mol −1 , and preexponential factor was 7.3*10 −2 min −1 . The turnover frequency for the supported catalysts was found in the range of 9.7*10 −4 -8.8*10 −2 min −1 . A conversion of 94.9 ± 2.3% was obtained under the optimized conditions, that is, 10 wt.% of the catalyst loading, 17.5 methanol to oil molar ratio, 4 MPa, and at 200°C in 10 hr.

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H3PW12O40-MAS-7 and H3PW12O40-MAS-9 composite catalysts exhibiting different structural orderings were assembled from zeolite beta and ZSM-5 precursors by a one-pot template-assisted self-assembly mechanism. Characterization results suggest that H3PW12O40 was encapsulated into the mesoporous framework of the aluminosilicates without alteration of mesoporosity of the composites. The sequential introduction of H3PW12O40 during the synthesis of MAS-7 and MAS-9 affected the surface morphologies. The textural characteristics of the composites were improved owing to the introduction of HPW after the addition of an inorganic precursor to the template leading to a material with a high BET surface area. As novel heterogeneous solid acid catalysts, the activity of the composites was determined for the biodiesel synthesis from the unrefined green seed canola oil, giving 95.4 ± 1.4 wt % methyl ester in 10 h at 180 °C with 5.5 wt % of catalyst and a 15.5:1 methanol to oil molar ratio. The recyclability of the composites is evaluated through four consecutive reactions.