Synthesis of NbFAPO-5 and NbFAPSO-5 Molecular Sieve by Hydrothermal Method and Comparison of Their XRD Patterns and Their Acidic Properties Evaluation by Infrared Spectroscopy
Mesoporous molecular sieves, NbFAPO-5 and NbFAPSO-5 were hydrothermally synthesized with AlPO-5 type structure. Characterization of these molecular sieves was performed by X-ray diffraction to determine their structure, ICP-EAS for their elemental composition and infrared spectrometry to access their acidic properties. X-ray diffraction patterns confirmed well AlPO-5 type structure. ICP-EAS analysis confirmed the incorporation of silicon (12.9%), aluminium (15.4%), phosphorous (21.9%), iron (5.62%) and niobium (0.39%) into AlPO-5 framework. Infrared spectrometry analysis showed that both Bronsted and Lewis sites were found in the synthesized samples. The presence of both Bronsted and Lewis acid site led to bifunctional function of NbFAPO-5 and NbFAPSO-5 molecular sieve in promoting both oxidation and esterification reactions. NbFAPSO-5 Bronsted acidity was higher than that of NbFAPO-5 and for Lewis acidity, NbFAPO-5 was higher than that of NbFAPO-5.
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