Transesterification of canola oil on potassium-supported TiO2 catalysts
ABSTRACT The transesterification reaction of canola oil was studied on titania-supported catalysts with varying loadings of potassium. It was found that the most active catalysts fall in the range where the adsorption/ desorption of CO2 was the highest. Total conversion to methyl esters was achieved on a catalyst with 20% K-loading under air conditions and with no in situ pre-treatment before reaction. The funding from the CIMAT project No. 11980002 is gratefully acknowledged for funding this work.
Chemical Reviews 07/2014; 114(19). DOI:10.1021/cr400634p · 45.66 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Pt nanoparticles (1.2–2.0 nm size) supported on Ce1–xTixO2−δ (x = 0, 0.2, 0.5, 0.8, and 1.0) carriers synthesized by the citrate sol–gel method were tested toward the water–gas shift (WGS) reaction in the 200–350 °C range. A deep insight into the effect of two structural parameters, the chemical composition of support (Ce/Ti atom ratio), and the Pt particle size on the catalytic performance of Pt-loaded catalysts was realized after employing in situ X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM) and HAADF/STEM, scanning electron microscopy (SEM), in situ Raman and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopies under different gas atmospheres, H2 temperature-programmed reduction (H2-TPR), and temperature-programmed desorption (NH3-TPD and CO2-TPD) techniques. The 0.5 wt % Pt/Ce0.8Ti0.2O2−δ solid (dPt = 1.7 nm) was found to be by far the best catalyst among all the other solids investigated. In particular, at 250 °C the CO conversion over Pt/Ce0.8Ti0.2O2−δ was increased by a factor of 2.5 and 1.9 compared to Pt/TiO2 and Pt/CeO2, respectively. The catalytic superiority of the Pt/Ce0.8Ti0.2O2−δ solid is the result of the support’s (i) robust morphology preserved during the WGS reaction, (ii) moderate acidity and basicity, and (iii) better reducibility at lower temperatures and the significant reduction of “coking” on the Pt surface and of carbonate accumulation on the Ce0.8Ti0.2O2−δ support. Several of these properties largely influenced the reactivity of sites (k, s–1) at the Pt–support interface. In particular, the specific WGS reaction rate at 200 °C expressed per length of the Pt–support interface (μmol CO cm–1 s–1) was found to be 2.2 and 4.6 times larger on Pt supported on Ce0.8Ti0.2O2−δ (Ti4+-doped CeO2) compared to TiO2 and CeO2 alone, respectively.The Journal of Physical Chemistry C 11/2013; 117(48):25467–25477. DOI:10.1021/jp406059h · 4.84 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Esterification of free fatty acids with alcohols catalytic by acid catalysts can synthesize sustainable production of biofuel. In this work, 12-tungstophosphoric acid was modified by picolinic acid to prepare solid acid catalyst (PA-HPW) and applied to the esterification, which was proved to be an efficient catalyst for the esterification of oleic acid and alcohols. For characterization of the catalysts, XRD, FT-IR, SEM and potentiometric titration method were employed. These analyses showed that there was no decomposition of the Keggin structure of 12-tungstophosphoric acid during preparation and esterification. The PA-HPW catalyst presented high acidity and good stability in esterification mixtures. Various reaction parameters, such as methanol/oleic acid molar ratio, catalyst dosage, reaction temperature and time were systematically examined. A quantitative conversion (100%) of oleic acid was achieved, using the most active modified catalyst at 80 degrees C with a 7 wt % catalyst/oleic acid ratio for 5 h, at a 10:1 of alcohol/acid mole ratio. The catalyst can be easily recovered and reused, which indicated that the PA-HPW catalyst is a promising new type of heterogeneous acid catalyst for conversion of free fatty acid feeds to biodiesel.Applied Energy 12/2014; 134:283–289. DOI:10.1016/j.apenergy.2014.07.099 · 5.26 Impact Factor