Preparation, Characterization, and Catalytic Activity of Tin (Antimony) Substituted and Lacunar Dawson Phosphotungstomolybdates for Synthesis of Adipic Acid

Tin (antimony) substituted and lacunar Dawson phosphotungstomolybdates (alpha 1-K10P2W12Mo5 square O-61, alpha 1-K8P2W12Mo5SnO61 and alpha-Cs4SnP2W12Mo6O62, and alpha-Cs3SbP2W12Mo6O62) were synthesized and characterized by Fourier Transform Infra Red (FTIR), nuclear magnetic resonance (P-31 NMR), Visible Ultra Violet (UV-Vis) spectroscopy, and X-ray diffraction (XRD). Their catalytic properties were examined in the oxidation reaction of cyclohexanone at 90 degrees C and that of cyclohexene at 70 degrees C to adipic acid (AA), in presence of hydrogen peroxide and in free solvent. The effects of catalyst/substrate molar ratios, hydrogene peroxide flow rate, heteropolysalt composition, and cyclohexanol addition on AA yields were studied. The Cs4SnP2W12Mo6O62 (the most efficient) led to 61 % of AA yield from the cyclohexanone oxidation using a catalyst/substrate molar ratio of 13.3x10(-4), H2O2 flow rate of 0.5 mL/h, and a reaction time of 20 h. Copyright (c) 2019 BCREC Group. All rights reserved