1,3-Butadiene → Tetrahydroanthraquinone

Participants

Reaction Steps

Process for the isolation of purified anthraquinone from crude anthraquinone which has been obtained by oxidation of naphthalene to give naphthoquinone, reaction of the oxidation product with butadiene to give tetrahydroanthraquinone, oxy-dehydrogenation of the reaction product with molecular oxygen to give a crude anthraquinone and optionally removal of naphthalene, phthalic anhydride and low-boiling substances from this crude anthraquinone, which comprises treating said crude anthraquinone with an oxygen compound of the elements of the first and/or second main group of the Periodic System in solid, pulverulent form and in an amount of 0.1 to 20% by weight relative to said crude anthraquinone at an elevated temperature, optionally in the presence of an organic solvent, and then isolating purified anthraquinone by subliming the pretreated anthraquinone in the presence of said oxygen compound at a temperature of about 190° to about 290° C. and a pressure of about 1 to about 90 mm Hg and then desubliming it under the same pressure, or by vaporizing the pretreated anthraquinone at a temperature of about 290° to about 380° C. and a pressure of about 90 to about 760 mm Hg and condensing the vapour under a pressure of about 90 to about 760 mm Hg.

Provenance & Evidence