The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 25, 1976
Filed:
Sep. 05, 1975
Mitsui Toatsu Chemicals, Incorporated, Tokyo, JA;
Abstract
Highly pure 5-nitro-1,4,4a,9a-tetrahydroanthraquinone can be obtained by subjecting 6-nitronaphthoquinone-containing crude 5-nitro-1,4-naphthoquinone to Diels-Alder condensation reaction with 1,3-butadiene in a solvent including benzene, an alkylated aromatic hydrocarbon such as toluene, xylene or the like, a halogenated aromatic hydrocarbon such as chlorobenzene, dichlorobenzene, or the like, or a halogenated aliphathic hydrocarbon such as trichloroethylene, perchloroethylene or the like, cooling the resulting reaction solution to crystallize the reaction product, and separating the thus crystallized product by filtration. 5-nitro-1,4,4a,9a-tetrahydroanthraquinone has a relatively small solubility in the above-mentioned solvents, while the solubility of 6-nitro-1,4,4a,9a-tetrahydroanthraquinone in the solvents is rather great, thus the above-mentioned solvents being effective for the separation of these compounds from each other. The oxidation and the subsequent reduction of the thus obtained 5-nitro-1,4,4a,9a-tetrahydroanthraquinone yields 1-aminoanthraquinone with a purity above 98 wt% and a 2-aminoanthraquinone content below 1 wt%. The above-mentioned solvents are also effective for purification of 6-nitro-1,4,4a,9a-tetrahydroanthraquinone-containing 5-nitro-1,4,4a,9a-tetrahydroanthraquinone by recrystallization.