Au/TiO2 nanocrystalline catalysts and application thereof

A nano-catalyst and nano-crystal technology, applied in the field of nano-materials, can solve the problems of low conversion rate of propylene oxide, low rate of propylene oxide, environmental pollution, etc.

Active Publication Date: 2014-10-29
UNIV OF SCI & TECH OF CHINA
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The chlorohydrin method causes serious pollution to the environment due to the use of chlorine gas in the production process, which produces a large amount of organic chlorides; the co-oxidation method produces a large number of co-products during the reaction process, and the market does not match the demand for propylene oxide and by-products. general use of the law
The direct epoxidation of propylene under the condition of oxygen or adding hydrogen is an ideal reaction with environmental friendliness and low energy consumption, which has important scientific research value, but the traditional Au / TiO 2 (P25) in H 2 and O 2 The conversion rate of catalytic propylene epoxidation to propylene oxide under the atmosphere is too low, and the rate of generating propylene oxide per unit mass of gold is relatively small, so finding a catalyst for the simple and efficient preparation of propylene epoxidation is a major challenge in this field. technical problems

Method used

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  • Au/TiO2 nanocrystalline catalysts and application thereof
  • Au/TiO2 nanocrystalline catalysts and application thereof
  • Au/TiO2 nanocrystalline catalysts and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] The main exposed (001) surface of TiO 2 (001) Preparation of nanocrystals:

[0030] Take 25ml of tetra-n-butyl titanate and 3ml of hydrofluoric acid in 50ml of polytetrafluoroethylene inner village and stir at room temperature for half an hour, then put it into a stainless steel jacket, keep it at 180°C for 24h, and centrifuge the obtained product after the reaction , washed repeatedly with ethanol and ultrapure water to obtain white TiO 2 (001) solid powder, and dried at 80°C for 12 hours, and then washed with 700ml 0.1M NaOH to obtain TiO 2 (001) solid powder, and then repeatedly washed with ethanol and ultrapure water, and finally a clean white TiO 2 (001) Solid powder.

[0031] Preparation of TiO as above 2 The method of (001) nanocrystals refers to the method provided by Xie Zhaoxiong et al. Materials such as tetra-n-butyl titanate, hydrofluoric acid, absolute ethanol and ultrapure water used in the preparation process are all purchased from the market.

Embodiment 2

[0033] The main exposed (100) facet of TiO 2 (100) Preparation of nanocrystals:

[0034] First synthesize Ti(OH) 4 , first prepare 0.43mol / L HCl solution, 5.5% and 4% ammonia solution by mass fraction, then take 20ml HCl solution in ice-water bath, then add 6.6ml TiCl dropwise 4 , to obtain clarified TiCl 4 solution. These clarified TiCl 4 The solution was added dropwise to 50ml of 5.5% ammonia solution to produce a white precipitate, and the pH of the reactant was adjusted to 6-7 with 4% ammonia solution. Then it was stirred for 2 h, and the resulting white precipitate was washed with ultrapure water until the AgNO 3 Solution detection No Cl in filtrate -1 . Then vacuum dry at 60°C for 12 hours to obtain white Ti(OH) 4 .

[0035] Using Ti(OH) 4 as a precursor to synthesize TiO 2 (100), 0.5g (NH 4 ) 2 SO 4 Dissolve in 15ml ultrapure water and 15ml isopropanol mixture, add 2g Ti(OH) 4 , and put it into a 50ml polytetrafluoroethylene inner village and stir at room...

Embodiment 3

[0038] Au / TiO loaded with Au mass fraction of 1% 2 (001) Preparation of nanocrystalline catalyst, and its activity in the reaction of propene epoxidation to propylene oxide:

[0039] With the TiO that 1g embodiment 1 makes 2 (001) nanocrystals are placed in a three-necked flask, then add 50ml of deionized water, and add Au and TiO 2 A gold precursor solution with a mass ratio of 1%, adjust the pH of the solution to 7-10, and stir at 60° C. for 1 h. Then the obtained product was filtered and washed until the filtrate was washed with AgNO 3 Solution until no precipitate can be detected. Finally, dry at 60°C for 12h in vacuum, and bake at 400°C for 2h in an air atmosphere.

[0040] The relevant catalytic performance test is done to the product obtained in the present embodiment below:

[0041] The propylene epoxidation reaction is carried out in a quartz reaction tube. 250mg of catalyst is added to the quartz reaction tube with quartz wool. The gas used is a mixture of propy...

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Abstract

The invention relates to different morphological Au / TiO2 nanocrystalline catalysts, a catalytic application thereof in preparing epoxy propane from propylene through epoxidation, and a preparation method thereof. The preparation method comprises the following steps: first, carrying out controlled synthesis so as to obtain TiO2 nanocrystalline in two different morphologies of a main exposure (001) surface and a main exposure (100) surface, placing the TiO2 nanocrystalline in a three-mouth flask, adding a certain amount of deionized water, adding a gold precursor solution accounting for 1% of the total weight of Au-TiO2, adjusting the pH value of the solution to 7 to 10, stirring for 1 hour at a temperature of 60 DEG C; filtering and washing the obtained products until the filtrate does not carry out reactions with a AgNO3 solution (namely no precipitate is generated any more), drying for 12 hours at a temperature of 60 DEG C in vacuum, and finally burning for 2 hours at a temperature of 400 DEG C in an air atmosphere so as to obtain the catalysts. The serial catalysts have excellent activity and selectivity in catalyzing propylene epoxidation reactions to prepare epoxy propane. The preparation method is simple, no harmful byproduct is generated, and the obtained catalysts can increase the conversion rate of propylene.

Description

technical field [0001] The invention belongs to the field of nanomaterials, in particular to an application of a nanomaterial in propylene epoxidation and a preparation method thereof, in particular to an Au / TiO with a morphology effect 2 Nanocrystalline catalyst, its preparation method, and its catalytic reaction in the preparation of propylene oxide by propylene epoxidation. Background technique [0002] Gold is an environmentally friendly noble metal with high catalytic activity and comprehensive excellent properties such as high temperature resistance, oxidation resistance, and corrosion resistance. It has become the most important catalyst material and is currently widely used. The vast majority of heterogeneous reaction catalysts are supported by noble metals, such as Au / Al 2 o 3 , Au / TS-1, Au / CeO 2 Wait. Due to its high catalytic activity and selectivity, gold catalysts play an extremely important role in petroleum, chemical, energy and other fields. [0003] In ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/52C07D303/04C07D301/10
CPCY02P20/52
Inventor 黄伟新陈士龙
Owner UNIV OF SCI & TECH OF CHINA
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