Synthesis And Properties Of Heteropoly Compounds Based On {W₉Mo₉}

Heteropoly compounds were widely used and have good application prospects.In this paper,composite material H₆P₂Mo₉W₉O₆₂/Zn?BDC??Bipy?_0.5,heteropoly acid salt K₆P₂W_18-xMo_xO₆₂?X=0,3,9,15,18?and organic inorganic hybrid materials Co₂?bpy?₃?ox?(P₂W_18-xMo_xO₆₂)·2?H₂bpy?·2H₂O?X=0,3,9,15,18?were synthesized by using hydrothermal method and impregnation methods,the structures of the material were characterized by FT-IR,XRD,NMR,EDX,electrochemical analysis,SEM,etc.Catalytic activity of composite material H₆P₂Mo₉W₉O₆₂/Zn?BDC??Bipy?_0.5to 3,4-two pyrimidine-2?H?ketone derivatives,the catalytic oxidation performance of heteropoly acid salt K₆P₂W_18-xMo_xO₆₂?X=0,3,9,15,18?and organic inorganic hybrid materials Co₂?bpy?₃?ox?(P₂W_18-xMo_xO₆₂)·2?H₂bpy?·2H₂O?X=0,3,9,15,18?on benzyl alcohol were explored.The main contents are as follows:Well-Dawsons H₆P₂Mo₉W₉O₆₂ under the condition of 140?for 6 h and metal-organic frameworks Zn?BDC??Bipy?_0.5 under the condition of 90?for 24 h were synthesized by hydrothermal method.Zn?BDC??Bipy?_0.5 was modified with Well-Dawsons heteropolyacid H₆P₂Mo₉W₉O₆₂ by impregnation method using organic metal frameworks?MOFs?as the carrier to increase the active site of composite materials H₆P₂Mo₉W₉O₆₂/Zn?BDC??Bipy?_0.5.Take H₆P₂Mo₉W₉O₆₂/Zn?BDC??Bipy?_0.5as catalyst,the experimental results showed that,under the conditions of fixed aromatic aldehyde feed of 0.04 mol;n?aromatic aldehyde??n?carbamide??n?ethyl acetoacetate?=1:1.5:1.4,the dosage of catalyst is at 2.0%of total mass of the starting materials,reaction temperature is at 105?,and reaction time is 60 min,the yield of the target products achieves 40.1⁹1.5%.After the catalyst is reused for 5times,the yield of the product is still 71.3%.Using Na₂WO₄·2H₂O and Na₂MoO₄·2H₂O as raw materials,the precursor Well-Dawsons H₆P₂Mo₉W₉O₆₂ was synthesized by hydrothermal method.The precursor was reacted with KCl to obtain the target product K₆P₂W₉Mo₉O₆₂.K₆P₂W₉Mo₉O₆₂ was used as catalyst and H₂O₂ was used as oxidant.Oxidation of benzyl alcohol was as a probe reaction.When the reaction temperature is 110?,reaction time is 8 h,oxidant dosage is 2.2 mL,the mass of the catalyst is 0.125 g,the conversion rate reached 82.3%,the selective rate reached 73.9%.When using different hetero atom ratio heteropolyacid salts K₆P₂W₁₈O₆₂,K₆P₂W₁₅Mo₃O₆₂,K₆P₂W₉Mo₉O₆₂,K₆P₂W₃Mo₁₅O₆₂,K₆P₂Mo₁₈O₆₂2 as catalysts,the selective rates of benzaldehyde were 18.4%,68.8%,73.9%,66.2%and 80.2%respectively.The conversion rates of benzyl alcohol were 11.5%,76.7%,82.3%,64.9%and 95.9%,respectively.Using K₆P₂W_18-xMo_xO₆₂?X=0,3,9,15,18?as precursor,organic inorganic hybrid material Co₂?bpy?₃?ox?(P₂W_18-xMo_xO₆₂)·2?H₂bpy?·2H₂O?X=0,3,9,15,18?were synthesized by hydrothermal method,taking Co₂?bpy?₃?ox?(P₂W₉Mo₉O₆₂)·2?H₂bpy?·2H₂O as catalyst and H₂O₂ as oxidant in the oxidation of alcohols for preparation of aldehyde,when the reaction temperature is 100?,reaction time is 8 h,the oxidant dosage is 3.2 mL,the mass of the catalyst is 0.1 g,the conversion rate was89.1%,the selective rate of benzaldehyde was 96.8%.When the anion is P₂W_18-XMo_XO₆₂^6-?X=0,3,9,15,18?,the order of conversion rate of benzyl alcohol is W₃Mo₁₅>W₉Mo₉>W₁₅Mo₃>Mo₁₈>W₁₈.The order of selectivity of benzaldehyde is W₉Mo₉>W₃Mo₁₅>W₁₅Mo₃>Mo₁₈>W₁₈.It shows that when the active center is P₂W₉Mo₉O₆₂^6-,the catalyst has the best catalytic effect.In the end,the catalyst is fully separate out and it can be recycled.After 5 times of full utilization,the conversion of benzyl alcohol is still 82.3%,indicating that the catalyst has a good stability.