Graphite-phase carbon nitride-modified silicon oxide porous microsphere-supported heterogeneous rhodium catalyst and preparation method and application thereof

A graphite-phase carbon nitride and heterogeneous catalyst technology, which is applied in the preparation of carboxylic acid by carbon monoxide reaction, organic compound/hydride/coordination complex catalyst, physical/chemical process catalyst, etc., can solve the problem of difficult preparation and collapse of catalyst structure Or reconstruction, recycling and reuse problems, etc., to achieve the effect of simple use method, simple reaction device, and low corrosion

Active Publication Date: 2021-07-09
JIANGSU SOPO CHEM +2
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  • Application Information

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Problems solved by technology

However, ideal heterogeneous (solid) catalysts have not been found so far, because their activity is far from meeting the requirements of industrialization.
[0004] In a homogeneous catalytic system, the effective electron-donating coordination system has a great influence on the catalytic activity of the catalyst. The graphitic carbon nitride has a stable structure and has a good electron-donating effect. Our experiments have proved that it is the same as rhodium, etc. The combination of noble metals can significantly improve the catalytic activity of metals, but it has been difficult to prepare graphitic carbon nitride structures suitable for use as supports for a long time
[0005] Previously, our research group designed a graphite-phase carbon nitride porous microsphere with high thermal stability and high activity as a catalyst carrier, and prepared a heterogeneous catalyst with much higher activity than the existing similar catalysts, although in a single catalytic reaction During the process, the catalyst showed high stability and high activity, but in the subsequent trial production process, it was found that during the catalyst recycling process, the graphite-phase carbon nitride crystal porous microspheres were prone to corrosion due to high temperature and strong acidic conditions. Collapse or crystal reconstruction, especially in the high-temperature treatment process of catalyst recovery, due to the residual acetic acid on the surface of the carrier and the high temperature of 500 ° C, it is easy to cause the structure of the catalyst to collapse or reconstruct, making recovery and reuse difficult

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  • Graphite-phase carbon nitride-modified silicon oxide porous microsphere-supported heterogeneous rhodium catalyst and preparation method and application thereof
  • Graphite-phase carbon nitride-modified silicon oxide porous microsphere-supported heterogeneous rhodium catalyst and preparation method and application thereof
  • Graphite-phase carbon nitride-modified silicon oxide porous microsphere-supported heterogeneous rhodium catalyst and preparation method and application thereof

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preparation example Construction

[0033] As an improvement, the preparation method of the graphite-phase carbon nitride-modified silicon oxide porous microspheres comprises the following steps:

[0034] Step 1: Weigh the precursor compound containing carbon and nitrogen elements together with water or alcohol solvent to form a 30%-50% precursor solution, dry the silicon oxide porous microspheres at high temperature to remove water, and quickly add them to In the precursor solution, the volume of silicon oxide porous microspheres is about 90% of the volume of the precursor solution; the alcohol solvent is methanol, ethanol or propanol;

[0035] Step 2, heat up the silicon oxide porous microspheres after absorbing the precursor solution to 80°C at a heating rate of 1°C / min, keep it warm for 3-5 hours, continue to heat up to 120°C and keep it for 2 hours, and dry it. According to the concentration of the precursor solution, sequentially Repeat step 1 and step 2, cycle 1-2 times;

[0036] In step 3, the temperatu...

Embodiment 1

[0047] Get 5 grams of graphite-phase carbon nitride-modified silica porous microsphere carriers, 20 mg of dichlorotetracarbonyl dirhodium (belonging to carbonyl rhodium), dissolve them in an appropriate amount of ethanol solution, stir and mix, put into a quartz tube after drying , Burning at 550°C for 2 hours under the protection of argon to become a catalyst containing 0.21% rhodium.

[0048] 5 grams of catalysts with a rhodium content of 0.21% are put into a column reactor, and carbon monoxide is introduced to remove the air in the column, then the temperature is raised to 180° C., and the partial pressure of carbon monoxide is maintained at 1 MPa. A mixture of methanol and methyl iodide (according to the molar ratio of 10:1) was injected into the reaction column at a rate of 1 ml / min with a pressure pump. Collect the cooled reaction product from the outlet of the reaction column. The conversion rate of methanol in the product was 83%, calculated based on converted methano...

Embodiment 2

[0053] Get 5 grams of silica porous microsphere carrier modified by carbon nitride of graphite phase, 48 mg of dirhodium dichlorotetracarbonyl, dissolve in ethanol solution, stir and mix, put into quartz tube after drying, under argon protection Burn at 300°C for 2 hours to become a catalyst containing 0.5% rhodium.

[0054] The rhodium content is that 0.5% catalyst 5 grams are put into the tube column reactor, remove the air in the tube column with carbon monoxide, then be warming up to 185 ℃, keep the carbon monoxide partial pressure as 1MPa, methyl alcohol and methyl iodide mixed solution (according to The molar ratio is 10:1) using a pressure pump to inject into the reactor at a rate of 1 ml / min. The cooled product was collected at the reactor outlet. The conversion rate of methanol in the product is 87%, calculated based on converted methanol, the yield of acetic acid is 74%, and the yield of methyl acetate is 23%.

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Abstract

The invention discloses a graphite-phase carbon nitride-modified silicon oxide porous microsphere-supported heterogeneous rhodium catalyst and a preparation method and application thereof. The catalyst adopts a stable silicon oxide porous material as a framework and employs carbon nitride as a carrier for surface modification, a rhodium compound is adsorbed, and then high-temperature oxygen-free treatment is conducted so as to obtain the heterogeneous rhodium catalyst for a carbonylation reaction of methanol. Accordign to the invention, methyl alcohol can be carbonylated into acetic acid and methyl acetate under mild conditions without a solvent by using methyl iodide as a cocatalyst; the prepared catalyst is stable in performance and high in activity, supported rhodium is not easy to fall off, the catalyst is stable in structure, and rhodium loss is not easy to cause; and the catalyst can still maintain good activity after being repeatedly used 7 times or more, and is easy to recycle and reuse.

Description

technical field [0001] The invention relates to the technical field of acetic acid preparation, in particular to a heterogeneous catalyst for graphite-phase carbon nitride-modified silicon oxide porous microspheres loaded with rhodium, a preparation method and application thereof. Background technique [0002] At present, the industrial production of methanol carbonylation to prepare acetic acid is prepared by using a rhodium catalyst through a homogeneous reaction, which has been widely promoted around the world. However, due to the complex equipment requirements for homogeneous catalysts, the difficulty in product separation, and the serious corrosion of the equipment by the reaction system during the reaction process, all equipment must use expensive special alloys, which brings great difficulties to industrial production. High-quality acetic acid with low impurity content requires complex processing. Because rhodium is a precious metal, its catalyst recycling is also ve...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J27/24C07C51/12C07C53/08B01J31/02
CPCB01J27/24C07C51/12B01J31/0231B01J35/0006C07C53/08Y02P20/584
Inventor 王忠华闫丰文朱桂生代松涛黄志军邵守言袁国卿赵禄强唐丽
Owner JIANGSU SOPO CHEM
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