Method for preparing 1,8-diaminonaphthalene by reducing 1,8-dinitronaphthalene with hydrazine hydrate

Abstract

The invention relates to a method for preparing 1,8-diaminonaphthalene by reducing 1,8-dinitronaphthalene with hydrazine hydrate. The 1,8-dinitronaphthalene, catalyst and polar organic solvent are added in a reactor with a stirring and reflux condenser, stirring is started, the temperature is increased to 45 DEG C to 115 DEG C, the hydrazine hydrate, the concentration of which is 40 percent to 80percent, is dripped within 1 to 3 hours, the temperature is kept for 3 to 8 hours, so that post-reaction solution is obtained, the post-reaction solution is filtered, the catalyst is recovered, filtrate is distilled to recover the polar organic solvent, so that feed solution is obtained, cold water is added in the feed solution, so that product is precipitated, and after filtration and distillation under reduced pressure, the 1,8-diaminonaphthalene is obtained; the molar ratio of the 1,8-dinitronaphthalene to the hydrazine hydrate is 1:(3 to 4); the dosage of the catalyst is 2 percent to 15 percent of the mass of the 1,8-dinitronaphthalene; and the mass ratio of the polar organic solvent to the 1,8-dinitronaphthalene is (3 to 20):1. The invention has the advantages of mild reaction condition, simple equipment, high product yield, stable quality and little environment pollution, and can realize mass production.

Description

technical field [0001] The invention relates to a method for preparing 1,8-diaminonaphthalene by reducing 1,8-dinitronaphthalene with hydrazine hydrate, which belongs to the field of chemical industry. Background technique [0002] At present, domestic mainly adopts iron powder reduction method (CN1100403A) to prepare 1,8-diaminonaphthalene, while developed countries such as Japan and the United States mainly adopt catalytic hydrogenation reduction (JP4154745A, GB1499699A, US4026944A), although domestic patent CN101575295A also reports two A method for preparing diaminonaphthalene by catalytic hydrogenation of nitronaphthalene, but there are no industrial examples, and the product quality and yield are unstable. [0003] The iron powder reduction method has a low product yield, accompanied by a large amount of iron sludge, and the three wastes are seriously polluted, so it is an obsolete process. Although the catalytic hydrogenation method has good product quality, less thre...

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Problems solved by technology

[0003] The iron powder reduction method has a low product yield, accompanied by a large amount of iron sludge, and the three wastes are seriously polluted, so it is an obsolete process. However, the catalytic hydrogenation method has good product quality, less three wastes, and simple post-treatment, but the reaction conditions are harsh and equipment investment is large. Generally, it is only used for large-scale production. It is still in the experimental stage in China and has not yet achieved industrialization.