In the present endeavor, amorphous
cerium phosphate (CP) and thorium phosphate (TP) have been synthesized
by the sol–gel method. Further, CP and TP also have been synthesized
under microwave irradiation to yield CPM and TPM. The materials have been characterized for elemental analysis (inductively
coupled plasma-atomic emission spectrometry, ICP-AES), spectral analysis
(Fourier transform infrared spectroscopy, FTIR), thermal analysis
(TGA), X-ray diffraction studies, scanning electron microscopy (SEM),
energy dispersive X-ray (EDX) analysis, Brunauer–Emmett–Teller
(BET) surface area analysis, and surface acidity (NH3-temperature
programmed desorption (TPD)). Chemical stability of the materials
in various acids, bases, and organic solvent media has been studied,
and their potential use as solid acid catalysts has been explored
by studying acetal formation. A simple, efficient, and highly eco-friendly
protocol is described for the acetalization of benzaldehyde, cyclohexanone,
acetophenone and benzophenone with pentaerythritol by varying parameters
such as reaction time, catalyst amount, and mole ratio of the reactants.
The catalytic activity of CP, TP, CPM, and TPM has been compared and correlated with surface properties of the
materials.