A kind of core-shell structure nickel-based dehydrogenation catalyst and preparation method thereof

Abstract

The invention relates to a nickel-based dehydrogenation catalyst with a core-shell structure and a preparation method thereof. The catalyst is prepared by first preparing Ni / Cu-MOF, and then etching away Cu in Ni / Cu-MOF by Pearson soft and hard acid-base principle. Ni / Cu-MOF etched material, then adding aluminum salt, in-situ growth of Ni-Al LDH on the Ni-MOF skeleton nickel surface of Ni / Cu-MOF etched product under alkaline conditions to obtain LDH-MOF derivatives, and finally in N 2 Calcining LDH-MOF derivatives at 400-600°C under atmosphere to obtain a nickel-based dehydrogenation catalyst with a core-shell structure. The core of the catalyst is a Ni carbonyl compound active component with a diameter of 10-100 nm, and the shell is a shell with a thickness of 20-100 nm. Ni-Al LDH, the catalyst can be used in electrolysis hydrogenation reaction and pyridine dehydrogenation to prepare bipyridine and other reactions, and has excellent dehydrogenation catalytic performance.

Description

technical field [0001] The invention relates to a nickel-based dehydrogenation catalyst with a core-shell structure and a preparation method thereof, belonging to the catalyst preparation technology in the technical field of industrial catalysis. Background technique [0002] The dehydrogenation reaction of hydrocarbons is a relatively common type of chemical reaction used in the petrochemical field, such as dehydrogenation of alkanes, dehydrogenation of olefins, side chain dehydrogenation of aromatics and dehydrogenation of alcohols. It has been reported that Ni-based catalysts show good catalytic activity in dehydrogenation reactions, and Ni-based catalysts have the advantages of high activity, low price and safe operation, so they have become the first choice in the field of dehydrogenation catalysis. Chinese patent CN101912781A discloses a method for preparing a dehydrogenation nickel-based / diatomite catalyst, which exhibits excellent catalytic activity in catalyzing the...

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Problems solved by technology

[0004] 2,2'-Bipyridine is an important "three-drug" intermediate and raw material for the preparation of photoelectric materials. The current synthesis methods mainly include pyridine carbonyl compound cyclization method, Ullmann method, sodium ammonia method, alkyne amine ring method, decarboxylation method, Oxidation method, alkyne nitrile ring method, pyran ammoniation method and pyridine dehydrogenation one-step direct coupling method, etc. Among them, Ullmann method and direct dehydrogenation coupling method have industrial application prospects, but Ullmann method needs to carry out halogenation to pyridine first. 2-halopyridine, then dehydrogenated and coupled to synthesize 2,2'-bipyridine, there are problems such as low production efficiency, many side reactions, and many wastes

The pyridine one-step direct dehydrogenation coupling method has the characteristics of short process and green environmental protection, and has become a research hotspot and difficulty. At present, Raney nickel is mainly used as the dehydrogenation catalyst, but Raney nickel is very easy to spontaneously ignite and has great safety hazards. It is carried out under anhydrous conditions, the operating conditions are harsh, and the catalyst Raney nickel is easily deactivated. Compared with the Raney Ni catalyst, the supported Ni-based catalyst has the advantages of easy preparation, low price, and safe operation. It is used as a pyridine dehydrogenation system. 2,2'-bipyridine catalyst is a suitable choice, and Ni-based supported catalyst catalyzes the reaction of pyridine dehydrogenation to 2,2'-bipyridine, due to the limitation of the reaction itself, the nitrogen atom in 2,2'-bipyridine Stronger electronegativity will form a strong coordination bond with Ni, making it difficult for the generated 2,2'-bipyridine to desorb from the catalyst or fall off with Ni, resulting in catalyst loss and reduced catalytic performance. Single-pass conversion and 2,2-bipyridine yield are generally very low, and 2,2'-bipyridine single-pass yield is generally less than 1%

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