Syntheses And Oxidative Desulfurization Properties Of Organic-inorganic Hybrids Based On High-nuclear Polyoxometalates

As people pay more and more attention to the environmental protection, the diesel desulfurization has been widely researched by chemists. Conventional hydrodesulfurization （HDS） is the currently adopted method in industry to remove the sulfur compounds in fuel, but it will cost much to remove the refractory sulfur-containing compounds such as dibenzothiophene （DBT） and its derivatives to become the ultra low sulfur diesel （ULSD）. Oxidative desulfurization （ODS） is regarded as a promising strategy to remove the refractory aromatic thiophenes. The synthesis of new POMs-based organic-inorganic hybrid materials have developed rapidly in recent years, however, the studies on the POMs-based organic-inorganic hybrid materials formed by highnuclear POMs and their application in the ODS process are rare. Here, we sccessfully synthesized three new organic-inorganic hybrid materials based on high-nuclear POMs, and characterized them by TG, FT-IR, 1H NMR, ICP, single X-ray diffraction, UV-vis, XRD and so on. And we studied the oxidative desulfurization properties of three compounds.1. Two novel surfactant-encapsulated high-nuclear polyoxometalates catalysts 1 and 2 formed by the polymerization of [HPMo₆O₂₁]^2- units have been prepared and their oxidative desulfurization properties have been studied. We investigated the oxidation desulfurization of 1 and 2 in the model oil with the hydrogen peroxide as oxidant under optimized reaction conditions and studied the influences of the different polymeric structure on catalytic performance. （DODA）20[（HPMo₆O₂1）₄（O₂CCH₂CO₂）₆]·27H₂O （1） （DODA）10[（HPMo₆O₂1）2（C2O4）₃]·13H₂O （2）2. We sccessfully synthesized a new POMs-based high-nuclear organic-inorganic hybrid 3 by aqueous solution reaction. （3）Compound 3 consists of dimeric [Mn₂V22O64]^10- polyoxoanions, metal-organo fragments [(C₆H₄NO₂Cu（H₂O）₄]²⁺ and lattice water molecules. The [Mn₂V22O64]^10- anion comprises two [MnV11O32]5- clusters of edge-shared VO6 octahedra linked by fusion at two vertices. A three-dimensional supramolecular structure is formed in 1 by the extensive hydrogen bond interaction among the terminal oxygen atoms of [Mn₂V22O64]^10- anions, the coordinated waters of Cu²⁺ions and crystal water molecules.3 represents a rare example of organic-inorganic hybrid based on [Mn₂V22O64]^10- polyoxoanion. What’s more,3 as a catalyst in the oxidation of sulfide desulfurization experiments on different thiophene sulfide also showed high catalytic activity.