Preparation method and application of dextrangel-supported nanogold catalyst

A technology of glucan gel and catalyst, which is applied in the field of preparation of glucan gel supported nano-gold catalyst, can solve the problems of poor dispersibility of the supported gold catalyst, large particle size of gold particles, and reduced catalytic efficiency, etc. The effects of physical and chemical stability, uniform particle dispersion and high catalytic activity

Inactive Publication Date: 2012-12-12
UNIV OF JINAN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The supported gold catalyst prepared by the impregnation method has poor dispersion, small loading capacity, and large gold particle size, and its catalytic performance is poor; the supported gold catalyst prepared by the co-precipitation method is embedded in the interior of the carrier due to a considerable number of gold particles. Particles embedded in the carrier cannot participate in the catalytic reaction, thus reducing the catalytic efficiency
The deposition-precipitation method deposits gold hydroxide on the carrier by controlling the pH value during synthesis to obtain a catalyst with low loading, small particle size and high activity, but the pH value is too low to prevent gold hydroxide from depositing, so this method It is only suitable for a specific carrier; the sol-gel method is to disperse the carrier precursor and the gold precursor together in a solvent, and then start to become a sol through hydrolysis and polymerization, and then generate a gel with a certain spatial structure, and then dry it and calcination to prepare a supported gold catalyst, so this method is only applicable to SiO 2 ,TiO 2 , ZrO 2 and Al 2 o 3 and other carriers

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] (1) Mercaptodextran gel: In a stoppered Erlenmeyer flask, add 10mL of thioglycolic acid (filter out the precipitate) and 10mL of tetrahydrofuran, add a drop of concentrated sulfuric acid, mix well, add 10g of dextran gel, stopper, in Stir and reflux at 65°C for 4 hours, then wash with deionized water and suction filter until the filtrate is neutral, wash with a small amount of ethanol, dry in an oven at 40°C, and store in a desiccator protected from light to obtain Mercaptodextran gel;

[0019] (4) Preparation of dextran gel-loaded nano-gold catalyst, adding 10 g of the above-mentioned mercapto-mercapto dextran gel to 100 mL 2.5×10 -3 mol / L chloroauric acid solution, use 6.0mol / L hydrochloric acid to adjust the acid concentration of the solution at 0.10mol / L, stir at room temperature for 40min, filter and separate the resulting solid part into 0.2mol / L NaBH 4 in the solution, stirred, heated to 70°C, reacted for 50 minutes, cooled, filtered, washed with distilled water...

Embodiment 2

[0021] (1) Mercaptodextran gel: In a stoppered Erlenmeyer flask, add 15mL of thioglycolic acid (filter out the precipitate) and 12mL of tetrahydrofuran, add two drops of concentrated sulfuric acid, mix well, add 12g of dextran gel, stopper, Stir and reflux at 60°C for 5 hours, then wash with deionized water and suction filter until the filtrate is neutral, wash with a small amount of ethanol, dry in an oven at 40°C, and store in a desiccator away from light. Obtain mercaptodextran gel;

[0022] (4) preparation of dextran gel-loaded nano-gold catalyst, adding 10 g of the above-mentioned mercapto dextran gel to 40 mL 5.0 × 10 -3 mol / L chloroauric acid solution, adjust the acid concentration of the solution to 0.50mol / L with 6.0mol / L hydrochloric acid, stir and react at room temperature for 20min, filter and separate the obtained solid part into 0.1mol / L NaBH 4 in the solution, stirred, heated to 75°C, reacted for 40 minutes, cooled, filtered, washed with distilled water, and dr...

Embodiment 3

[0024] (1) Mercaptodextran gel: In a stoppered Erlenmeyer flask, add 8mL of thioglycolic acid (filter out the precipitate) and 10mL of tetrahydrofuran, add a drop of concentrated sulfuric acid, mix well, add 10g of dextran gel, stopper, in Stir and reflux for 3.5 hours at 70°C, then wash with deionized water and suction filter until the filtrate is neutral, wash with a small amount of ethanol, dry in an oven at 40°C, and store in a desiccator protected from light. Obtain mercaptodextran gel;

[0025] (4) Preparation of dextran gel-loaded nano-gold catalyst, adding 5 g of the above-mentioned mercapto dextran gel to 30 mL6.0×10 -3 mol / L chloroauric acid solution, use 6.0mol / L hydrochloric acid to adjust the acid concentration of the solution at 0.2mol / L, stir at room temperature for 40min, filter and separate the resulting solid part into 0.3mol / L NaBH 4 in the solution, stirred, heated to 65°C, reacted for 60 minutes, cooled, filtered, washed with distilled water, and dried at...

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PUM

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Abstract

The invention discloses a preparation method and application of a dextrangel-supported nanogold catalyst. The preparation method comprises the following steps: 1) adding thioglycolic acid, tetrahydrofuran, dextrangel and concentrated sulfuric acid according to percentage by mass, carrying out thermostatic reaction at 65+ / -5 DEG C, carrying out vacuum filtration, washing, and drying to obtain sulfhydryl dextrangel; and 2) adding the sulfhydryl dextrangel into a chloroauric acid solution, regulating the acidity of the solution with hydrochloric acid, reacting at 70+ / -5 DEG C, separating to obtain a solid, reducing with NaBH4, separating, washing, and drying to obtain the dextrangel-supported nanogold catalyst. The invention has the characteristics of simple preparation method, uniform high gold particle dispersion and high supporting rate; the dextrangel has the characteristics of light weight, low price, high stability and the like, and is degradable and environment-friendly; and when being used for ethanol selective oxidation reaction, the catalyst disclosed by the invention has the characteristics of mild reaction conditions, high catalytic activity, high selectivity, low consumption and the like.

Description

technical field [0001] The invention relates to the technical field of preparation of supported catalysts, in particular to a preparation method and application technology of a dextran gel-supported nano-gold catalyst. Background technique [0002] With the intensification of global pollution and serious damage to the environment, sustainable development is imperative. The basic requirements for sustainable development are energy saving, emission reduction and cost reduction, which is also the essence of green catalytic reactions, which requires high atomic utilization under mild conditions. Nano-gold catalysts can catalyze different organic compounds under mild conditions. carry out a selective oxidation reaction. [0003] Gold has always been considered to be chemically inert, and it is far less active than platinum group metals in terms of catalytic performance. Since Haruta et al. reported in 1987 that gold-supported catalysts have high activity for low-temperature cata...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J31/06C07C47/07C07C45/38C07C69/14C07C67/40
Inventor 李慧芝许崇娟宋桂兰杨春霞
Owner UNIV OF JINAN
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