Method for preparing azobenzene derivatives

Abstract

The invention belongs to the field of organic synthesis, in particular relates to a method for synthesizing azobenzene compounds and discloses a method for preparing azobenzene derivatives. In the method, one of nitrobenzene derivatives is used as a reactant; one or a mixture of two of platinum nanowires or palladium nanowires is used as a catalyst; and potassium hydroxide, sodium hydroxide, (CH3)3CONa or (CH3)3COK is used as alkali. The method comprises the following steps of: adding the reactant, the catalyst and the alkali into a solvent; and performing a reaction for 2 to 24 hours at the temperature of between 20 and 140 DEG C under normal pressure in the hydrogen atmosphere to obtain azobenzene. The platinum nanowires or the palladium nanowires are taken as the catalyst and the suitable alkali and solvent are adopted, so that the reaction conditions of preparing the azobenzene derivatives are mild and the reaction can be carried out under the conditions of normal pressure and room temperature. Moreover, the conversion rate and selectivity are higher and is about 90 percent, a reactor is environment-friendly, the catalyst is easy to separate and can be recycled, and reagents which cause serious pollution to the environment, such as nitrite and the like, are not used.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a synthesis method of azo compounds, in particular to a method for preparing azobenzene and derivatives thereof by catalytic reduction of aromatic compounds with nitro groups. Background technique [0002] Azo compounds are important organic synthesis intermediates in the chemical industry, and can be used to synthesize antioxidants, dyes, active components, polymer modifiers, adhesives, photoresists, photosensitive materials, food additives and drugs, etc. . [0003] In the prior art, the method for synthesizing azobenzene compounds is usually: (1) reduction of nitroaromatic compounds, (2) oxidation of aromatic amines, and (3) by diazotization of aniline and in liquid phase Electron-rich aromatic compound reaction diazotization method. The first two methods usually use some metals that are more polluting to the environment, such as lead, tellurium, etc. (referring ...

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Problems solved by technology

[0005] Other existing supported metal nanocatalysts (Au, Pd, Pt nanoparticles, etc.) are used in the reduction process of nitrobenzene, which often require harsh reaction conditions such as high temperature and high pressure, and the reaction is difficult to control in one step of azobenzene, resulting in The azobenzene usually continues to be hydrogenated to generate hydroazobenzene, and the hydrogenated azobenzene will also continue to react to eventually generate aniline

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