A phosphoric acid-modified montmorillonite-supported tungsten oxide catalyst, preparation method and application

A technology of tungsten oxide and montmorillonite, which is applied in the preparation of carbon-based compounds, organic compounds, physical/chemical process catalysts, etc., can solve the problems of unfavorable catalyst regeneration, catalyst deactivation, poor thermal stability, etc., and achieve good Development prospect, high catalytic activity and good stability

Inactive Publication Date: 2018-03-30
ZHEJIANG COLLEGE OF ZHEJIANG UNIV OF TECHOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the solid acid catalyst supported by tungstophosphopolyacid shows strong Brnsted acid sites, its thermal stability is poor, which is not conducive to the regeneration of the catalyst. When the regeneration temperature exceeds 500 °C, the supported tungstophosphopolyacid decomposes into phosphorus-containing Oxide and bulky 3D WO 3 crystal grains, leading to severe deactivation of the catalyst, therefore, the calcination temperature of the solid acid catalyst supported by tungstophosphoheteropolyacid is generally lower, which is 250-400 °C
[0005] So far, there are no domestic and foreign literature reports on solid acid catalysts loaded with tungsten oxide after phosphoric acid activated montmorillonite

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025]In this example, 5 g of montmorillonite was dispersed in 25 ml of phosphoric acid aqueous solution with a mass percent concentration of 15% (the mass ratio of solute phosphoric acid, water, and montmorillonite was 0.8: 4.3: 1), and stirred at 60°C for 4 hours. , cooled, centrifuged, precipitated, washed with deionized water until neutral, and dried at 80°C for 10 h to obtain phosphoric acid-modified montmorillonite. Mix 0.43g of ammonium metatungstate tetrahydrate, 0.08g of oxalic acid dihydrate, 1ml of ethanol and 5g of deionized water to prepare a transparent dipping solution. Disperse 4g of phosphoric acid-modified montmorillonite in the impregnation solution (the mass of tungsten accounts for 8% of the mass of phosphoric acid-modified montmorillonite), let it stand at room temperature for 10 hours, dry at 80°C for 12h, and then dry it at 400°C in air Roasting in the atmosphere for 3 hours, naturally cooling to room temperature, tableting, granulating, and passing thr...

Embodiment 2

[0028] In this example, 5 g of montmorillonite is dispersed in 25 ml of phosphoric acid aqueous solution with a concentration of 15% by mass (the mass ratio of solute phosphoric acid, water, and montmorillonite is 0.8 : 4.3 : 1), and the reaction is stirred at 65°C for 6 hours , cooled, centrifuged, precipitated, washed with deionized water until neutral, and dried at 80°C for 10 h to obtain phosphoric acid-modified montmorillonite. Mix 0.68g of ammonium paratungstate tetrahydrate, 0.12g of oxalic acid dihydrate, 2ml of ethanol and 7g of deionized water to prepare a transparent impregnation solution. Disperse 4g of phosphoric acid-modified montmorillonite in the impregnating solution (the mass of tungsten accounts for 12% of the mass of phosphoric acid-modified montmorillonite), let stand at 45°C for 6 hours, dry at 80°C for 10h, and then dry at 350°C Roasting in air atmosphere for 4 hours, cooling naturally to room temperature, tableting, granulating, and passing through a 40...

Embodiment 3

[0031] In this example, 5 g of montmorillonite is dispersed in 25 ml of phosphoric acid aqueous solution with a concentration of 20% by mass (the mass ratio of solute phosphoric acid, water, and montmorillonite is 1:4:1), and after stirring and reacting at 80°C for 6 hours , cooled, centrifuged, precipitated, washed with deionized water until neutral, and dried at 80°C for 10 h to obtain phosphoric acid-modified montmorillonite. Mix 0.91g of ammonium paratungstate tetrahydrate, 0.12g of oxalic acid dihydrate, 2ml of ethanol and 8g of deionized water to prepare a transparent impregnation solution. Disperse 4g of phosphoric acid-modified montmorillonite in the impregnating solution (the mass of tungsten accounts for 16% of the mass of phosphoric acid-modified montmorillonite), let stand at 45°C for 8 hours, dry at 80°C for 8h, and then dry at 350°C Roasting in air atmosphere for 4 hours, cooling naturally to room temperature, tableting, granulating, and passing through a 40-60 m...

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PUM

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Abstract

The invention discloses a phosphoric acid modified montmorillonite loaded tungsten oxide catalyst, a preparation method and application.The preparation method includes: using a phosphoric acid solution to modify montmorillonite, and adopting a soaking method to load tungsten oxide on phosphoric acid modified montmorillonite, wherein active species are H+ among montmorillonite layers, Al3+ outside a montmorillonite framework and WOx with different tungsten-oxygen atom coordination structures, and x is greater than or equal to 2.7 and less than or equal to 3; soaking phosphoric acid modified montmorillonite in a water solution of ammonium tungstate hydrate, oxalate dihydrate and low carbon, drying, and baking to obtain the phosphoric acid modified montmorillonite loaded tungsten oxide catalyst.The catalyst can be used for catalyzing glycerol gas-phase selective dehydration to produce acrylic aldehyde, glycerol conversion rate is 70-100%, acrylic aldehyde selectivity is 75-95%, and the catalyst is simple in preparation process, high in catalytic performance and long in service life.

Description

technical field [0001] The invention relates to a phosphoric acid-modified montmorillonite-supported tungsten oxide catalyst, a preparation method, and an application in the gas-phase selective dehydration of glycerin to produce acrolein. Background technique [0002] Montmorillonite is a natural mineral, rich in resources, cheap and friendly to the environment. Its main component is aluminosilicate, which has a layered structure. The laminates are composed of silicon-oxygen tetrahedrons sandwiching aluminum-oxygen octahedrons in the form of a "sandwich". A certain amount of Na is adsorbed between the laminates. + , Ca 2+ Isohydrated cations, the cations between the layers are exchangeable. After montmorillonite is modified by acid activation, interlayer pillaring, surface loading, grafting and other methods, the specific surface area increases, showing mesoporosity, strong adsorption and acidity, so that it can meet different uses and requirements. Therefore, modified mo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J27/188C07C47/22C07C45/52
CPCB01J27/188C07C45/52C07C47/22
Inventor 俞卫华周春晖童东绅
Owner ZHEJIANG COLLEGE OF ZHEJIANG UNIV OF TECHOLOGY
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