Preparation of quinizarin
40 g phthalic anhydride and 10 g of pure hydroquinone are heated for 3 hours in a flask in an oil bath at 170-180° C with 200 g pure conc. sulfuric acid and 20 ml of water. It is then heated for 1 hour at 190-200° C. The hot solution is gently poured into about a litre of cold water in a large basin. The whole is then heated to boiling and filtered hot with suction. The residue is again extracted with boiling water and filtered hot. It is then boiled up with 400 ml glacial acetic acid and filtered hot, to remove carbonaceous matter. The filtrate is diluted with its own volume of hot water and filtered, the residue being again extracted with boiling glacial acetic acid and again precipitated with hot water. The crude quinizarin which separates on cooling is filtered, well washed with water and dried on a water bath. It is then quickly distilled from a hard glass retort with a large flame, a porcelain mortar being used as receiver. The distillate is then powdered and recrystallized from glacial acetic acid and washed with more dilute acetic acid and finally with water. The yield of quinizarin is 20%. Dark red needles from toluene, orange-yellow leaves from glacial acetic acid; m.p. 195° C; insoluble in water.
Systematic organic chemistry, by W. M. Cumming, 108-109, 1937.
1,4-dihydroxy-9,10-anthraquinone, 1,4-dihydroxyanthraquinone, 1,4-dihydroxyanthraquinone, radiacal ion (1-), anthrarufin, quinizarin
Quinizarin, 1,4-Dihydroxyanthraquinone, 81-64-1, 1,4-dihydroxyanthracene-9,10-dione, Quinizarine, Chinizarin, Solvent Orange 86, Smoke Orange R, 1,4-Dihydroxy-9,10-anthraquinone, Macrolex Orange GG, 1,4-Dihydroxyanthrachinon, 1,4-Dioxyanthraquinone, Anthraquinone, 1,4-dihydroxy-, 9,10-Anthracenedione, 1,4-dihydroxy-, 1,4-Dihydroxyanthra-9,10-quinone, 1,4-Doa, 1,4-Dihydroxy-anthraquinone, 1,4-dihydroxy-9,10-anthrachinon, 1,4-Doa [Russian], C.I. 58050, NSC 15367, NSC 646569, CHEMBL17594, CCRIS 3524, 1,4-DIHYDROXY-9,10-ANTHRACENEDIONE, CHEBI:37487, HSDB 5242, 1,4-Dioxyanthraquinone [Russian], GUEIZVNYDFNHJU-UHFFFAOYSA-N, 1,4-Dihydroxyanthrachinon [Czech], EINECS 201-368-7, NSC646569, CI 58050, 9, 1,4-dihydroxy-, AI3-17616, WLN: L C666 BV IVJ DQ GQ, 86321-26-8, 1,4-dihydroxy-9,10-dihydroanthracene-9,10-dione, Pigment Violet 12, PubChem10115, AC1Q6JWB, ACMC-209uj4, Q906_ALDRICH, AC1L1N2Y, DSSTox_CID_24464, DSSTox_RID_80248, UNII-8S496ZV3CS, 1,4 Dihydroxy-Anthraquinone, DSSTox_GSID_44464, KSC490O1R, SCHEMBL160038, 8S496ZV3CS, MEGxp0_001867, SCHEMBL2639287, 37480_FLUKA, ACon1_000101, CTK1B4776, CTK1B4777, CTK3J0718, MolPort-000-645-297, BB_NC-0468, KST-1B8934, NSC15367, NSC40899, ZINC3847495, 9,10-Dihydroxy-1,4-anthraquinone, Tox21_302041, ANW-43838, AR-1B7775, BBL010354, BDBM50240382, CCG-48149, DNC000885, DNC001184, NSC-15367, NSC-40899, NSC229036, SBB069501, STK264108, ZINC03847495, 1,4-dihydroxy-anthracene-9,10-dione, AKOS001595052, AKOS022660870, ZINC100244462, 1,4-Dihydroxy-9,10-anthracene-dione, 1,4-Dihydroxyanthra-9,10-quinone #, MCULE-3130863142, NSC-229036, NSC-646569, RP28421, RTR-031317, TRA0070047, CAS-81-64-1, 1,10-Anthracenedione, 4,9-dihydroxy-, 1,4-Anthracenedione, 9,10-dihydroxy-, NCGC00160196-01, NCGC00160196-02, NCGC00255951-01, AC-11267, AJ-45865, AK155883, AN-24046, CJ-10811, K456, KB-64549, LS-20669, NCI60_001089, PL004102, PL037790, PL037838, PL038054, PL040039, SC-06850, AB1002106, KB-150799, TR-031317, D0243, FT-0657575, ST24036851, ST50330576, AE-641/02529036, S14-0959, SR-01000637713-1, W-104202, 3B1-008222, 9,10-DIHYDROXY-1,4-DIHYDROANTHRACENE-1,4-DIONE, F1565-0160, 4,9-DIHYDROXY-1,10-DIHYDROANTHRACENE-1,10-DIONE, 103220-12-8, 38572-74-6, 38572-75-7, InChI=1/C14H8O4/c15-9-5-6-10(16)12-11(9)13(17)7-3-1-2-4-8(7)14(12)18/h1-6,15-16