Synthesis And Catalytic Performance Of Dawson Type Molybdovanadophosphoric Heteropoly Compounds

Synthesized a series of Dawson-type vanadium phosphomolybdate heteropoly acid and Dawson-type heteropoly compounds substituted by quaternary ammonium salt and pyridinium salt. The synthesized catalysts were characterized with FT-IR, X-ray, 31PNMR and other methods .The results show that the synthesized compounds have the characteristics of Dawson-type structure. Through cyclohexanol and cyclohexene oxidation as probe reaction to study the catalysts properties systemic .Dawson-type vanadium phosphomolybdate heteropoly acid have both strong acidic and oxidizability, which is a multi-functional environment-friendly catalyst. It shown the good homogeneous features and strong catalytic properties in the catalytic system of cyclohexanol to cyclohexanone used H₂O₂ as oxidant. H₈P₂MO₁₆V₂O₆₂ have the highest catalytic activity. Surveyed these parameters have beening impacted to the reaction including different vanadium content catalyst, solvent type, amount of catalyst, oxidant dosage, reaction time and reaction temperature using cyclohexanol as substrate,and gained the best reaction conditions.The experimental system has prominently advantages such as simple, convenient operation, mild reaction conditions and so on.A series of Dawson-type vanadium phosphomolybdate quaternary ammonium salt were synthesized, using H₂O₂ as oxidant to study the synthesized vanadium phosphomolybdate Dawson-type heteropoly acid quaternary ammonium salt phase transfer catalyst catalytic activity in system of cyclohexene liquid-phase selective oxidation to anti--1,2 - cyclohexanediol. Using gas chromatography - mass spectrometry （GC-MS）combined to characterize the oxidation products.Investaged systemic the relationship between reaction conditions with catalytic activity. It can accelerate the reaction in cyclohexene / H₂O₂ peroxide-water two-phase reaction with introduction of heteropoly acid quaternary ammonium salt phase transfer catalyst, it has the full response, and the system shows high catalytic activity.