A core-shell structure hydrodechlorination catalyst, its preparation method and application

Abstract

The invention discloses a core-shell structure hydrodechlorination catalyst, a preparation method and application thereof. The catalyst comprises: a carrier, the carrier is a monolithic activated carbon carrier; an active metal supported on the carrier, the active metal selected from At least one selected from palladium, platinum, iridium, and nickel; the second metal supported on the carrier, the second metal is selected from one of copper, tin, silver, and zinc; the catalyst has a wrapping structure, and the core part is is the active metal, and the shell layer is the second metal. The catalyst of the invention has high activity and stability, can be used in hydrodechlorination reaction, and can improve the reaction selectivity.

Description

technical field [0001] The invention relates to the field of catalysts, in particular to a core-shell structure hydrodechlorination catalyst, a preparation method thereof, and the application of the core-shell structure hydrodechlorination catalyst in gas phase hydrodechlorination reaction, especially in Application of trifluorotrichloroethane in the preparation of chlorotrifluoroethylene. Background technique [0002] The catalytic hydrodechlorination technology, which replaces the traditional chemical reduction method, has attracted widespread attention in the important monomer reactions for the synthesis of hydrofluorocarbons and other fluorine-containing materials, and is considered to be one of the most economical, green and most promising methods at present. one. At present, common hydrodechlorination catalysts mainly use palladium as the main active component, and magnesium, cobalt, copper, bismuth, etc. as auxiliary agents. Hydrodechlorination performance. [0003...

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Problems solved by technology

[0004] European patent EP0747337B1 and Chinese patent CN1065261A disclose a bimetallic composite carbon-supported catalyst, the bimetal is formed by compounding at least one VIII group metal and copper, wherein copper accounts for 12 to 22% of the total mass of the catalyst; the bimetal The composite catalyst can be used in the hydrodechlorination reaction of CFC-113, but the reaction product is chlorotrifluoroethylene and trifluoroethylene or tetrafluoroethylene, and chlorotrifluoroethylene cannot be selectively obtained

[0005] European Patent EP0416615A1 discloses Fe, Ni, Cu, Sn, Zn, Cr or their oxides as catalyst active components, silica, magnesium oxide, alumina, zirconia, Y-type zeolite, silica-alumina , silicon carbide, diatomaceous earth, etc. as a carrier catalyst, the catalyst can be applied to CFC-113 hydrodechlorination to prepare chlorotrifluoroethylene, but the selectivity of the catalyst varies greatly when using different active components or carriers, and the highest Only about 80%, which makes the application of this catalyst have certain limitations

[0006] Chinese patent CN1351903A discloses a quaternary catalyst with precious metal ruthenium or palladium or platinum and copper as the main active component, adding lanthanum-rich mixed rare earth or metal lanthanum, and alkali metal lithium as modification aids, and using coconut shell activated carbon as the carrier. Catalyst, the life of the catalyst is about 600 hours, but in the absence of modifying aids, the selectivity of the catalyst is only 70-80%, and the method provided by this patent compares the selection of active components and modifying aids restricted

[0008] The above-mentioned hydrodechlorination catalysts all have low catalytic activity and poor stability. When applied to hydrodechlorination reactions, there is generally a problem of low reaction selectivity. Therefore, it is necessary to develop a catalyst with high activity, high selectivity and stable New catalysts with high performance are particularly important

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