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

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.H₂]²⁺[pydc]²⁻ (LH₂), (pyda.H₂ = 2,6-pyridine diammonium and pydc = 2,6-pyridinedicarboxylate) and ammonium vanadate, the five coordinated V(V) complex, [pyda.H][V(pydc)O₂], {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.