Sonochemical synthesis of vanadium complex nano-particles: a new precursor for preparation and evaluation of V2O5/Al2O3 nano-catalyst in selective oxidation of methanol to methylal

摘要

In this study, an ionic complex of V(V) was synthesized by using ultrasonic method, and it was used as a precursor for production of a new catalyst for selective preparation of methylal or dimethoxymethane (DMM). By reaction between an ionic ligand [pyda.H-2](2+)[pydc](2-) (LH2), (pyda.H-2 = 2,6-pyridine diammonium and pydc = 2,6-pyridinedicarboxylate) and ammonium vanadate, the five coordinated V(V) complex, [pyda.H][V(pydc)O-2], {2,6- diaminopyridinum 2,6-pyridinedicarboxylatodioxovanadate(V)}, VLH2 was synthesized. The prepared complex VLH2 was characterized by SEM, thermal analysis TGA/DTA, FT-IR spectroscopy and X-ray diffraction studies. The results showed that the yield of the reaction was increased up to 64%. The average particle sizes of the obtained complex VLH2 were about 50-60 nm. Also, the nano-catalyst of V2O5/Al2O3 was synthesized by impregnation method and was prepared as a nano-catalyst with average particles sizes of 50-60 nm, and its characterization was performed by XRD, EDX and SEM methods. Finally, the prepared catalyst was used to converting of methanol to methylal at different process conditions.