Toluene → 1-Aminoanthraquinone

Participants

Reaction Steps

A solution of 100 parts of 5-nitro-1,4,4a,9a-tetrahydroanthraquinone in 400 parts of toluene, 1000 parts of toluene-containing mother liquor and a solution of 8.8 parts of sodium bisulfide in 400 parts of water are charged simultaneously to a tube reactor (volume: 100 ml) with static mixing elements. The average residence time is c. 3 minutes. The feed temperature of the components is regulated such that the reaction mixture leaves the reactor at 160° C. and is separated continuously in a separating vessel under pressure (10 bar) into an aqueous and an organic phase. The pressure is relaxed in the working up reactor containing the organic phase, which is cooled to room temperature. The product is isolated by filtration, washed with toluene and dried under vacuum at 80° C. The aqueous phase is extracted with the mother liquor, a portion of which is recycled to the reactor. In stationary operation, 86 parts of 1-aminoanthraquinone are obtained per hour in 99% purity (layer chromatography), corresponding to a yield of 98% of theory, based on 5-nitrotetrahydroanthraquinone.

Provenance & Evidence