Adsorption of Wells-Dawson tungsten heteropolyacid on sol-gel alumina: structural features and thermal stability.
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.
Tarlani
A
A
Department of Chemistry, University of Tehran, Tehran, Iran.
Abedini
M
M
Khabaz
M
M
Amini
M Mohammadpour
MM