Phosphorus-containing Multiple Substituted Heteropoly Acids With Keggin Structure And Their Reversible Phase Transformation-type Ionic Liquids

Heteropoly acids, an important kind of solid acids with polynuclear and oxygen bridges, have extensive potential aplications in the fields of catalysis, electrochemistry, photochemistry, materials science, biology and medicine, due to their special structure, unique physical, chemical and biological properties.Two kinds of vanadium-substituted ternary and quaternary heteropoly acids with Keggin structure H4PMo11VO40·8H2O (PMo11V) and H5PWgMoV2O40·10H2O (PW9MoV2), have been synthesized by the ether extraction method. Structure and thermal stability of the products are characterized by EA, IR, UV, XRD and TG-DTA. Besides, the proton conductivities of the two heteropoly acids are measured by electrochemical impedance measurement. Results show that they have good proton conductivities at room temperature, which demonstrates that they are solid high-proton conductors. The proton conduction mechanisms of the products, which determined through the measurement of proton conductivities at different temperatures, are Vehicle mechanism.Moreover, a serious of polyoxometalate-based reversible phase transformation ionic liquids,[TBTA]6PW9V3O40,[TBTP]6PW9V304o,[TBTP]4PW11V04o,[TBTP]4PMo11V04o and [TBTP]5PW9MoV204o, have been synthesized from tributyltetradecylammonium bromide (TBTAB) and tributyltetradecylphosphonium chloride (TBTPC) and as-synthesized Keggin strucute heteropoly acids (H4PW11VO40, H4PMO11VO40, H6PW9V3O40and H5PW9M0V2O40). Based on this, the ionic liquids are discussed by specific classification approach. Structure and thermal stability of the products are characterized by IR, UV, XRD and TG-DTA, and their electrochemical properties are investigated. Small angle X-ray diffraction patterns indicate that phosphonium-based ionic liquids possess layered structures. TG-DTA curves indicate that they are new temperature control type ionic liquids which can exhibit a reversible phase transformation process below100℃. Their ionic conductivities increase with higher temperature and follow the Arrhenius behavior in the measured temperature region.