Double-metal material supported phosphotungstic acid catalyst as well as preparation method and application thereof to cellulose hydrolysis

A phosphotungstic acid and catalyst technology, applied in the field of materials, can solve the problems of structural collapse, MIL-101 structural stability and water stability obstacles, and achieve the effects of preventing loss, maintaining acid catalytic activity, and improving water stability.

Active Publication Date: 2019-05-17
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, the stability of MIL-101 structure, especially water stability, has always been the bottleneck hindering its industrial application as a carrier to catalyze cellulose h

Method used

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  • Double-metal material supported phosphotungstic acid catalyst as well as preparation method and application thereof to cellulose hydrolysis
  • Double-metal material supported phosphotungstic acid catalyst as well as preparation method and application thereof to cellulose hydrolysis
  • Double-metal material supported phosphotungstic acid catalyst as well as preparation method and application thereof to cellulose hydrolysis

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Composite bimetallic Ni / MIL-101 (Cr) synchronous immobilized phosphotungstic acid catalyst is prepared by the following method: Weigh the central metal ion Cr respectively 3+ and metal ions Ni 2+ Metal salts of phosphotungstic acid (PTA), terephthalic acid, 2,5-dichloroterephthalic acid (TA-Cl) and 2-aminoterephthalic acid (TA-NH 2 ), Cr 3+ The amount is 2mmol, Ni 2+The amount of Ni / (Cr+Ni)=0.2 is 0.5 mmol. The amounts of phosphotungstic acid, terephthalic acid, 2,5-dichloroterephthalic acid and 2-aminoterephthalic acid were 2mmol, 1mmol, 0.5mmol, 0.5mmol respectively, and 0.35mmol of citric acid was added, and Mix in 70mL of pure water and sonicate, transfer the sonicated solution to a polytetrafluoroethylene reactor and heat at a constant temperature of 220°C for 8h, wait to cool to room temperature, centrifuge the resulting solution, and use N,N-dimethyl Wash the solid twice with formamide, each washing time is 1 h, and continue to wash the solid several times wi...

Embodiment 2

[0033] Synthesize material PTA@MIL-101-NH according to the step in embodiment 1 2 -Cl, PTA@Ni-MIL-101-NH 2 -Cl(1), PTA@Ni-MIL-101-NH 2 -Cl(2), respectively weigh 1g of the above three materials into a 100mL saline bottle, add 50mL of distilled water and mix well, then let it stand at room temperature. Take the supernatant at the 1st, 3rd, 5th, 7th, 10th, and 15th day respectively, filter through a 0.22 μm filter membrane and measure its chromium ion content by ion chromatography, which is the chromium ion leaching concentration of the material in distilled water, which is used to reflect Material stability in water. PTA@MIL-101-NH 2 -Cl, PTA@Ni-MIL-101-NH 2 -Cl(1), PTA@Ni-MIL-101-NH 2 -Chromium ion leaching concentration of Cl(2) in distilled water changes with leaching time.

[0034] Such as figure 2 As shown, it can be seen that the chromium ion leaching concentration of the three materials increases with the prolongation of the leaching time, and PTA@MIL-101-NH 2 T...

Embodiment 3

[0036] Synthesize material PTA@MIL-101-NH according to the step in embodiment 1 2 -Cl, PTA@Ni-MIL-101-NH 2 -Cl(1), PTA@Ni-MIL-101-NH 2 -Cl(2), applying the phosphotungstic acid catalyst to cellulose hydrolysis, comprising the following steps: adding 0.12g of PTA@Ni-MIL-101-NH to 10mL distilled water 2 -Cl (add the same 0.12g of PTA@MIL-101-NH in the control experiment 2 The same amount of pure phosphotungstic acid catalyst in -Cl), and 0.04 g of microcrystalline cellulose were added at the same time, heated at a constant temperature at 180 ° C and continuously stirred for 11 h, and centrifuged after the reaction. The solid residue precipitated at the bottom of the centrifuge tube after centrifugation is the large-pore metal-organic framework material of immobilized PTA used to catalyze the hydrolysis of microcrystalline cellulose after the reaction. It can be reused after washing with distilled water and drying at 80°C for 16 hours .

[0037] Under the same test conditions...

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Abstract

The invention discloses a double-metal material supported phosphotungstic acid (PTA) catalyst as well as a preparation method and application thereof to cellulose hydrolysis. The method comprises thefollowing steps: introducing transition metal ions Ni<2+> when an organic ligand is coordinated with metal to form competition coordination with central metal ions Cr<3+>; adding organic acid to accelerate the coordination of composite double-metal MOFs (Metal Organic Frameworks) and realize the effect of a mineralizing agent; introducing -NH2 and phosphotungstic acid to realize chemical supporting of PTA through electrostatic interactions, so as to synthesize the catalyst. According to the catalyst disclosed by the invention, a hydrogen bond is formed through a heavy-current negative group and cellulose to adsorb the cellulose, so that directed transformation from the cellulose to glucose is realized. Meanwhile, an inner hydrogen bond effect of the cellulose also can be weakened through the hydrogen bond effect and the crystallization degree is reduced so that the catalyst is easier to hydrolyze and the hydrolysis efficiency is improved. In a catalyst synthesis process, solutions of HF (Hydrofluoric Acid) acid, sodium hydroxide and the like are not added, so that the catalyst is green and environmentally friendly.

Description

technical field [0001] The invention belongs to the field of materials, and in particular relates to a bimetallic material immobilized phosphotungstic acid catalyst, a preparation method and application in cellulose hydrolysis. Background technique [0002] Countercation H of Keggin-type heteropolyacids + Completely dissociated in water, showing the key to strong Bronsted acidity to promote the breakage and hydrolysis of cellulose glycosidic bonds. At the same time, it counterbalances the cation H + After dissociation, the electronegativity of the outer oxygen atom of the heteropolyacid anion increases, which can form a hydrogen bond with the -OH of the cellulose to absorb it, promote the hydrolysis of cellulose and reduce the glucose degradation reaction caused by the contact between the heteropolyacid and glucose. Occurrence is of great significance for the directional conversion of cellulose to glucose. Phosphotungstic acid (H 3 PW 12 o 40 , Phosphotungstic Acid, PTA...

Claims

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Application Information

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IPC IPC(8): B01J31/22B01J37/10B01J37/34C13K1/02
Inventor 王艳万金泉韩劲椰马邕文
Owner SOUTH CHINA UNIV OF TECH
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