High-dispersion polyoxometallate magnetic microsphere catalyst, and preparation method and application thereof

Abstract

The invention belongs to the technical field of loaded polyoxometallate catalysts, and provides a high-dispersion polyoxometallate magnetic microsphere catalyst, and a preparation method and application thereof so as to overcome the defects that polyoxometallate used as a catalyst is small in specific surface area, few in reaction activity sites, prone to aggregation, soluble in water, difficult to separate and recycle and the like. Dawson type phosphotungstate is loaded onto a CS@Fe3O4 microsphere by a covalent bonding method, and a covalent loaded Dawson type phosphotungstate magnetic microsphere P2W17-CS@Fe3O4-1 is obtained; or, Keggin type phosphotungstate and the Dawson type phosphotungstate are respectively loaded to an organic modified magnetic Fe3O4 microsphere by an electrostaticbonding method, and loaded Keggin type phosphotungstate and loaded Dawson type phosphotungstate are obtained. The dispersity and the specific surface area of the polyoxometallate are improved, the catalytic oxidation activity of the polyoxometallate and the oxidation efficiency of tetrahydrothiophene are improved, and a magnetic carrier provides favorable conditions for catalyst separation and recycling.

Description

technical field

[0001] The invention belongs to the technical field of supported polyoxometalate catalysts, and in particular relates to a highly dispersed polyoxometalate magnetic microsphere catalyst and its preparation method and application. The Dawson type polyacid is combined with an electrostatic combination method by covalent bonding. Keggin-type and Dawson-type polyacids were respectively loaded on the organically modified magnetic microsphere carrier. Background technique

[0002] Polyoxometalates (POMs) are composed of early transition metals MO x Polyoxometallic coordination clusters are assembled by sharing corners, planes and edges, and have rich topological structures and compositions, which determine their chemical and physical properties, the most prominent of which are catalytic properties, which are widely used in catalysis , medicine, materials chemistry and other fields. As a homogeneous catalyst, it is used in the desulfurization of hydrogen peroxide ...

Examples

Embodiment 1

[0023] Embodiment 1: the Fc of chitosan modification 3 o 4 Covalent loading of P on magnetic microspheres 2 W 17 Composite catalyst P 2 W 17 -CS@Fe 3 o 4 -1 preparation: the steps are as follows: 156 mg KH-560 and 1.0 g P 2 W 17 Add it to a mixed solution of 30 mL of acetonitrile and water ((V / V)=1:2), adjust the pH of the solution to 2, react at room temperature for 6 h, and then pour the reaction solution into a beaker. Then containing 0.84 gNBu 4 Add 5 mL of Br aqueous solution to the above reaction solution, the solution turns white, and viscous precipitates form at the bottom, filter, wash with ethanol and water in sequence, and dry with ether to obtain a white solid powder, which is epoxy-modified tungsten phospholipid Salt P 2 W 17 -EPO; then 0.3 g CS@Fe 3 o 4 Microspheres were added to 30 mL of DMF, N 2 Under protection, add 0.1 g NaOH solid and 0.3 gP 2 W 17 -EPO,N 2 Under protection, raise the temperature to 60 °C, react for 24 h, cool to room temper...

Embodiment 2

[0024] Embodiment 2: the Fc of chitosan modification 3 o 4 Covalent loading of P on magnetic microspheres 2 W 17 Composite catalyst P 2 W 17 -CS@Fe 3 o 4 -1 preparation: the steps are as follows: 256 mg KH-560 and 2.0 g P 2 W 17 Add it to a mixed solution of 40 mL of acetonitrile and water ((V / V)=2:2), adjust the pH of the solution to 3, react at room temperature for 8 h, and then pour the reaction solution into a beaker. Then containing 0.84 gNBu 4 Add 7 mL of Br aqueous solution to the above reaction solution, the solution turns white, and a viscous precipitate forms at the bottom. Then, filter, wash with ethanol and water in sequence, and dry with ether to obtain a white solid powder, which is epoxy-modified Phosphotungstate P 2 W 17 -EPO; then 0.4 g CS@Fe 3 o 4 Microspheres were added to 40 mL of DMF, N 2 Under protection, add 0.2 g Na 2 CO 3 solid and 0.4 g P 2 W 17 -EPO,N 2 Under protection, the temperature was raised to 70 °C, reacted for 25 h, cooled...

Embodiment 3

[0025] Embodiment 3: the Fc of chitosan modification 3o 4 Covalent loading of P on magnetic microspheres 2 W 17 Composite catalyst P 2 W 17 -CS@Fe 3 o 4 -1 preparation: the steps are as follows: 356 mg KH-560 and 3.0 g P 2 W 17 Add it to a mixed solution of 50 mL of acetonitrile and water ((V / V)=2:3), adjust the pH of the solution to 4, react at room temperature for 9 h, and then pour the reaction solution into a beaker. Then containing 0.84 gNBu 4 9 mL of aqueous solution of Br was added to the above reaction solution, the solution turned white, and a viscous precipitate formed at the bottom. Then, it was filtered, washed with ethanol and water in sequence, and dried with ether to obtain a white solid powder, which was epoxy-modified Phosphotungstate P 2 W 17 -EPO. Then 0.5 g CS@Fe 3 o 4 Microspheres were added to 50 mL of DMF, N 2 Under protection, add 0.3 g NaHCO 3 Solid and 0.5 g epoxy-modified phosphotungstate P 2 W 17 -EPO,N 2 Under protection, raise t...

technical field

[0001] The invention belongs to the technical field of supported polyoxometalate catalysts, and in particular relates to a highly dispersed polyoxometalate magnetic microsphere catalyst and its preparation method and application. The Dawson type polyacid is combined with an electrostatic combination method by covalent bonding. Keggin-type and Dawson-type polyacids were respectively loaded on the organically modified magnetic microsphere carrier. Background technique

[0002] Polyoxometalates (POMs) are composed of early transition metals MO x Polyoxometallic coordination clusters are assembled by sharing corners, planes and edges, and have rich topological structures and compositions, which determine their chemical and physical properties, the most prominent of which are catalytic properties, which are widely used in catalysis , medicine, materials chemistry and other fields. As a homogeneous catalyst, it is used in the desulfurization of hydrogen peroxide ...

Examples

Embodiment 1

[0023] Embodiment 1: the Fc of chitosan modification 3 o 4 Covalent loading of P on magnetic microspheres 2 W 17 Composite catalyst P 2 W 17 -CS@Fe 3 o 4 -1 preparation: the steps are as follows: 156 mg KH-560 and 1.0 g P 2 W 17 Add it to a mixed solution of 30 mL of acetonitrile and water ((V / V)=1:2), adjust the pH of the solution to 2, react at room temperature for 6 h, and then pour the reaction solution into a beaker. Then containing 0.84 gNBu 4 Add 5 mL of Br aqueous solution to the above reaction solution, the solution turns white, and viscous precipitates form at the bottom, filter, wash with ethanol and water in sequence, and dry with ether to obtain a white solid powder, which is epoxy-modified tungsten phospholipid Salt P 2 W 17 -EPO; then 0.3 g CS@Fe 3 o 4 Microspheres were added to 30 mL of DMF, N 2 Under protection, add 0.1 g NaOH solid and 0.3 gP 2 W 17 -EPO,N 2 Under protection, raise the temperature to 60 °C, react for 24 h, cool to room temper...

Embodiment 2

[0024] Embodiment 2: the Fc of chitosan modification 3 o 4 Covalent loading of P on magnetic microspheres 2 W 17 Composite catalyst P 2 W 17 -CS@Fe 3 o 4 -1 preparation: the steps are as follows: 256 mg KH-560 and 2.0 g P 2 W 17 Add it to a mixed solution of 40 mL of acetonitrile and water ((V / V)=2:2), adjust the pH of the solution to 3, react at room temperature for 8 h, and then pour the reaction solution into a beaker. Then containing 0.84 gNBu 4 Add 7 mL of Br aqueous solution to the above reaction solution, the solution turns white, and a viscous precipitate forms at the bottom. Then, filter, wash with ethanol and water in sequence, and dry with ether to obtain a white solid powder, which is epoxy-modified Phosphotungstate P 2 W 17 -EPO; then 0.4 g CS@Fe 3 o 4 Microspheres were added to 40 mL of DMF, N 2 Under protection, add 0.2 g Na 2 CO 3 solid and 0.4 g P 2 W 17 -EPO,N 2 Under protection, the temperature was raised to 70 °C, reacted for 25 h, cooled...

Embodiment 3

[0025] Embodiment 3: the Fc of chitosan modification 3o 4 Covalent loading of P on magnetic microspheres 2 W 17 Composite catalyst P 2 W 17 -CS@Fe 3 o 4 -1 preparation: the steps are as follows: 356 mg KH-560 and 3.0 g P 2 W 17 Add it to a mixed solution of 50 mL of acetonitrile and water ((V / V)=2:3), adjust the pH of the solution to 4, react at room temperature for 9 h, and then pour the reaction solution into a beaker. Then containing 0.84 gNBu 4 9 mL of aqueous solution of Br was added to the above reaction solution, the solution turned white, and a viscous precipitate formed at the bottom. Then, it was filtered, washed with ethanol and water in sequence, and dried with ether to obtain a white solid powder, which was epoxy-modified Phosphotungstate P 2 W 17 -EPO. Then 0.5 g CS@Fe 3 o 4 Microspheres were added to 50 mL of DMF, N 2 Under protection, add 0.3 g NaHCO 3 Solid and 0.5 g epoxy-modified phosphotungstate P 2 W 17 -EPO,N 2 Under protection, raise t...

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