Process for preparing aminoanthraquinones
AssigneeMitsui Toatsu Chemicals, Inc.
InventorsYutaka Hirai, Katsuharu Miyata, Tagui Osawa, Muneyasu Samecima, Ken Mukai, Koichi Yoshiura, Hidetoshi Mori
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Abstract
A process for preparing aminoanthraquinones of high purity, which comprises catalytically hydrogenating nitroanthraquinones in the suspended state in an aqueous medium in the presence of a hydrogenating catalyst. In a preferred embodiment, the catalytic hydrogenation may be carried out in the presence of an organic or inorganic base, followed, if desired, by oxidizing the hydrogenation product.
Claims9
A process for preparing aminoanthraquinones, which comprises catalytically hydrogenating a nitroanthraquinone of the general formula ##STR2## wherein X.sub.1 represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, a carboxyl group or a phenoxy group whose benzene nucleus optionally contains a substituent, X.sub.2 represents a hydrogen atom, a hydroxyl group or an amino group, and Y.sub.1 and Y.sub.2, independently from each other, represent a hydrogen atom, a halogen atom, a nitro group, an amino group, a hydroxyl group, a lower alkyl group, a lower alkoxy group or a phenoxy group whose benzene nucleus optionally contains a substituent, with the proviso that when the nitro group is bonded to the 1-position, X.sub.1, X.sub.2, Y.sub.1 and Y.sub.2 do not at the same time represent a hydrogen atom,
- in the suspended state in an aqueous medium in the presence of a hydrogenating catalyst.
Dependencies are inferred from the claim text.