Nitrogen-doped carbon material encapsulated cobalt catalyst and method of using the catalyst to prepare secondary amine compounds

Abstract

The present invention discloses a nitrogen-doped carbon material encapsulated cobalt catalyst and a method of using the catalyst to prepare secondary amine compounds. The preparation method of the catalyst comprises the following steps: 1) silica sol is added into a 2-methylimidazole solution and dispersed uniformly to obtain liquid sol, a stirring is conducted while adding cobalt nitrate liquid into the liquid sol, a stirring reaction is conducted for 3-10 h, and after the reaction is completed, centrifuging, filtering, washing and drying are conducted to obtain ZIF-67@SiO<2> materials; 2) under nitrogen protection, the ZIF-67@SiO<2> materials are calcined at 400-1,200 DEG C for 6-10 h, the calcined materials are soaked with hydrofluoric acid solution, the soaked calcined materials are water washed to neutral, the washed calcined materials are dried to obtain CN@Co materials. The method of using the catalyst to prepare the secondary amine compounds is as follows: in an organic solvent, nitro-compounds, formic acids, carbonyl compounds and the CN@Co materials are added, nitrogen is ventilated to replace oxygen in the reaction system, and the reaction is conducted at 90-220 DEG C for 15-18 hours in an air isolation condition to obtain the secondary amine compounds. The catalyst can be used in the preparation of the secondary amine compounds, reduces the requirements and costs of the reaction to devices and is relatively high in reaction selectivity and yield.

Description

technical field [0001] The invention relates to the technical field of catalysts and preparation of secondary amine compounds, and more specifically relates to a nitrogen-doped carbon material-wrapped cobalt catalyst and a method for preparing secondary amine compounds using the same. Background technique [0002] Amine compounds are important chemical raw materials and fine chemical intermediates, and their synthesis is the most studied reaction in synthetic chemistry. At present, the industrial synthesis of amines mainly adopts the method of hydrogenation and reduction of nitro compounds with noble metals. In this way, primary amines are prepared, and then secondary amines and their derivatives can be further synthesized by reacting with halogenated aromatic hydrocarbons, alcohols or carbonyl compounds. . [0003] At present, the nucleophilic substitution reaction using halogenated aromatics is the main way to prepare secondary amines, but this method requires quantitativ...

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Problems solved by technology

Matthias Beller used cobalt catalyst and hydrogen reductive coupling to synthesize secondary amine [Nature Protocol[J], 2015,10,549.] The yield reached more than 80%, Yong Cao et al. used gold catalyst and formic acid reductive coupling to synthesize secondary amine amines[Green Chemistry[J],2016,18,2507], but the use of noble metals, high-pressure hydrogen requirements for equipment and danger limit the application of these methods

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