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A kind of ferromolybdenum catalyst with core-shell structure and its preparation and application

A core-shell structure and catalyst technology, which is used in catalyst activation/preparation, oxidation to prepare carbonyl compounds, physical/chemical process catalysts, etc. problem, to achieve the effect of high catalytic performance

Active Publication Date: 2022-02-11
SOUTHWEST RES & DESIGN INST OF CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the catalyst prepared by this method has good activity, due to the structural characteristics of the precipitated bulk catalyst, the molybdenum in it is easy to sublimate and lose, resulting in unstable physical structure and catalytic performance of the catalyst, and shortened service life. There are also problems such as iron ions cannot be completely precipitated and lost, the preparation steps and cycle are long, and more waste water is generated.
The sol-gel method is also a commonly used method to prepare the catalyst. There are also problems such as the molybdenum of the prepared catalyst is volatile and lost, the preparation steps and cycle are long, and the generation of waste water is large. At the same time, there are also problems such as washing, filtering and molding difficulties.
Although the solid-phase mixing method does not have the above-mentioned other problems, there is still the problem that the obtained catalyst molybdenum is easy to lose, and because mechanical mixing is a key step, the energy consumption of the catalyst preparation is high and the contact reaction between the phases cannot be fully contacted, resulting in its structure. relatively poor performance
[0004] The impregnation method is a simple and efficient catalyst preparation method, but so far, there is no information on the technology for preparing molybdenum-iron catalysts by this method

Method used

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  • A kind of ferromolybdenum catalyst with core-shell structure and its preparation and application
  • A kind of ferromolybdenum catalyst with core-shell structure and its preparation and application
  • A kind of ferromolybdenum catalyst with core-shell structure and its preparation and application

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preparation example Construction

[0022] A method for preparing a molybdenum-iron catalyst with a core-shell structure, comprising the following steps: preparing a ferric nitrate solution, weighing dried molybdenum trioxide, completing the process of impregnating a molybdenum carrier with an iron-containing solution under the action of ultrasonic waves, followed by drying, roasting, A core-shell ferromolybdenum catalyst was formed.

[0023] The molar fraction of the solute in the ferric nitrate solution is 1.0-5.0 mol / L, and the solvent is water, ethanol or acetone.

[0024] The molybdenum trioxide is a mesoporous material with a large specific surface and is dried at 100-120° C. for 0.5-3.0 hours before use.

[0025] The process of impregnating the molybdenum carrier with the iron-containing solution is: adding molybdenum trioxide to the ferric nitrate solution or adding the ferric nitrate solution dropwise into the molybdenum trioxide.

[0026] The power of the ultrasonic wave is 50-100W, and the vibration ...

Embodiment 1

[0034] Dry molybdenum trioxide at 105°C for 2.0h; prepare a 4.5mol / L aqueous solution of ferric nitrate; weigh 30.0g of dried molybdenum trioxide and place it in an ultrasonic oscillator with a power setting of 100W, and add 15.4mL of Ferric nitrate solution; dry the impregnated carrier without solution on the surface at 100°C for 15 hours; then calcinate at 600°C for 1 hour to obtain the core-shell structure ferromolybdenum catalyst.

[0035] The catalyst is used in the oxidation of methanol to formaldehyde at a reaction temperature of 298°C. After the tail gas is absorbed by water, trace amounts of carbon monoxide and carbon dioxide are analyzed. Methanol and formaldehyde in the absorption liquid are detected on the Agilent chromatogram, and the obtained data are calculated according to the following formula Catalyst performance indicators:

[0036]

[0037]

[0038]

[0039]

[0040] Y FA= x MeOH ×S FA

[0041] Note: X MeOH —Methanol conversion rate per pas...

Embodiment 2

[0045] Dry molybdenum trioxide at 120°C for 2.5h; prepare 3.6mol / L ethanol solution of ferric nitrate; weigh 30.0g of dry molybdenum trioxide and place it in an ultrasonic oscillator with a power setting of 90W, and add 29.0mL nitric acid to it Iron solution; the impregnated carrier without solution on the surface is dried at 80°C for 8 hours; then calcined at 450°C for 2 hours to obtain the molybdenum-iron catalyst with core-shell structure.

[0046]The catalyst was used in the reaction of methanol oxidation to formaldehyde at a reaction temperature of 340°C, and the following performance data were obtained through gas-liquid phase product analysis and experimental data calculation:

[0047] X MeOH / %

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Abstract

The invention belongs to the field of carbon-chemical industry, and specifically relates to a core-shell structure ferromolybdenum catalyst and its preparation and application. The preparation process is as follows: preparing ferric nitrate solution, weighing dried molybdenum trioxide, completing the process of impregnating molybdenum carrier with iron-containing solution under the action of ultrasonic waves, and then drying, calcining and molding to obtain molybdenum-iron catalyst with core-shell structure. The method not only has simple process, few steps and short period, but also solves the problem of iron loss in the traditional method, and does not generate waste water in the preparation process. The ferromolybdenum catalyst with core-shell structure provided by the invention is composed of uniformly distributed and synergistic two-phase iron molybdate and molybdenum trioxide, and constitutes a core-shell structure in which an iron molybdate layer coats molybdenum trioxide particles microscopically. This structure effectively inhibits the volatilization and loss of molybdenum trioxide, ensures the stability of the catalyst element composition, physical structure, and physical and chemical properties, and exhibits excellent activity, selectivity, and stability when used in the oxidation of methanol to formaldehyde.

Description

technical field [0001] The invention belongs to the field of carbon-chemical industry, and relates to a novel structure ferromolybdenum catalytic material and its preparation and use, in particular to a core-shell structure ferromolybdenum catalyst prepared by an ultrasonic-assisted impregnation process and its use in methanol oxidation to produce high-concentration formaldehyde use in . Background technique [0002] my country is the world's largest producer and consumer of formaldehyde. In the future, with the further increase in the consumption of resins, paints, (polyoxymethylene) and other products and the rise of new products such as acrylic acid (ester) and polyoxymethylene dimethyl ether, my country's demand for high-concentration formaldehyde will increase day by day. As we all know, the iron-molybdenum process is an advanced process for the production of concentrated formaldehyde, but the ferro-molybdenum catalyst used in this process in my country relies heavily ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J23/881B01J35/00B01J37/02B01J37/34C07C45/29C07C47/052
CPCB01J37/343B01J37/0207B01J35/008B01J23/881C07C45/29C07C47/04
Inventor 程金燮赵安民陈鹏李扬张新波苏敏郭雄黄宏王华丁明月姚佩
Owner SOUTHWEST RES & DESIGN INST OF CHEM IND
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