title: Adsorption of Wells-Dawson tungsten heteropolyacid on sol-gel alumina: structural features and thermal stability.
abstract: The Wells-Dawson tungsten heteropolyacid, H6P2W18O62 supported on sol-gel and non-sol-gel alumina has been investigated by infrared spectroscopy (IR), thermal analysis (TGA/DSC), and X-ray diffraction (XRD). X-ray diffraction indicates that the heteropolyacid primary structure in bulk form holds up to 350 degrees C and by supporting it on the sol-gel alumina the thermal stability rose to 650 degrees C. UV-vis spectroscopy showed that the sol-gel alumina has a higher tendency to adsorb Wells-Dawson tungsten heteropolyacid than the non-sol-gel alumina. The heteropolyacid showed higher interaction with the sol-gel alumina than with the non-sol-gel. Esterification of propanoic acid with hexanol in the presence of alumina-supported heteropolyacid revealed that the acidic character of the heteropolyacid remains active to some extent.
authors.affiliation: Department of Chemistry, University of Tehran, Tehran, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Tarlani
authors.forename: M
authors.initials: M
authors.lastname: Abedini
authors.forename: M
authors.initials: M
authors.lastname: Khabaz
authors.forename: M Mohammadpour
authors.initials: MM
authors.lastname: Amini