Structure-activity relations in Cs-doped heteropolyacid catalysts for biodiesel production

K. Narasimharao, D.R. Brown, A.F. Lee, A.D. Newman, P.F. Siril, S.J. Tavener, K. Wilson

Research output: Contribution to journalArticle

Abstract

A series of insoluble heteropolytungstate (H3PW12O40 HPW) salts, CsxH3−xPW12O40 (x=0.9–3x=0.9–3), were synthesized and characterized using a range of bulk and surface sensitive probes including N2 porosimetry, powder XRD, FTIR, XPS, 31P MAS NMR, and NH3 calorimetry. Materials with Cs content in the range x=2.0–2.7x=2.0–2.7 were composed of dispersed crystallites with surface areas ∼100 m2 g−1 and high Brönsted acid strengths [ΔH0ads(NH3)=−150 kJmol−1], similar to the parent heteropolyacid. The number of accessible surface acid sites probed by α -pinene isomerization correlated well with those determined by NH3 adsorption calorimetry and surface area measurements. CsxH3−xPW12O40 were active toward the esterification of palmitic acid and transesterification of tributyrin, important steps in fatty acid and ester processing for biodiesel synthesis. Optimum performance occurs for Cs loadings of x=2.0–2.3x=2.0–2.3, correlating with the accessible surface acid site density. These catalysts were recoverable with no leaching of soluble HPW.
Original languageEnglish
Pages (from-to)226-234
Number of pages9
JournalJournal of Catalysis
Volume248
Issue number2
Early online date25 Apr 2007
DOIs
Publication statusPublished - 10 Jun 2007

Keywords

  • biodiesel
  • transesterification
  • triglyceride
  • esterification
  • fatty acids
  • solid acid
  • heterogeneous catalysis
  • heteropolyacids
  • XPS

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    Narasimharao, K., Brown, D. R., Lee, A. F., Newman, A. D., Siril, P. F., Tavener, S. J., & Wilson, K. (2007). Structure-activity relations in Cs-doped heteropolyacid catalysts for biodiesel production. Journal of Catalysis, 248(2), 226-234. https://doi.org/10.1016/j.jcat.2007.02.016