Acid anthracene red

Acid chrome red, acid anthracene red, acid alizarine red, anthracene chrome red, acid alizarine garnet, azo alizarine Carmoisine, chrome fast Bordeaux, cbrome fast garnet, chromotropes, diamond red, eriochrome red, eriochrome Bor- deaux, omega chrome red, oxychrome garnet, palatine chrome red, eriochrome olive, palatine chrome violet, anthracene chrome violet, acid chrome blue, azi chrome blue, chrome fast blue, chromotrope blue, omega chrome blue. 

Zone refining purified naphthalene from anthracene, 2,4-dinitrophenylhydrazine, methyl violet, benzoic acid, methyl red, chrysene, pentacene and indoline. 

Carminic acid (7-a-D-glucopyranosyl-9,10-dihydro-3,5,6,8-tetrahydroxy-l-methyl-9,10-dioxo-2-anthracene carboxylic acid. Neutral Red 4 Cl 75470) [1260-17-9] M 492.4, m... 

Identification of Aromatic Hydrocarbons. Picric acid combines with many aromatic hydrocarbons, giving addition products of definite m.p. Thus with naphthalene it gives yellow naphthalene picrate, C oHg,(N08)jCeHiOH, m.p. 152°, and with anthracene it gives red anthracene picrate, C 4Hio,(NOj)jCeHjOH, m.p. 138 . For practical details, see p. 394. 

Make a concentrated solution of anthracene in hot acetone. To about 2 ml. of this solution add a cold concentrated acetone solution of picric acid drop by drop, and note the formation of a red coloration which becomes deeper on further addition of the acid. If excess of picric acid is added, however, the solution becomes paler in colour, and this is to be avoided if possible. Boil to ensure that both components are in solution and then transfer to a small porcelain basin or watch-glass ruby-red crystals of anthracene picrate separate out on cooling. The product, however, is often contaminated with an excess of either anthracene or of picric acid, which appear as yellowish crystals. 

Alizarin Red S [3,4-dihydroxy-9,10-dioxo-2-anthracene sulphonic acid, Na salt. H20 ]... 

Crude anthracene (about 40%) is mixed in a vessel fitted with a mechanical stirrer, with 1J times its weight of benzol or solvent naphtha (90% at 160°) this specification means that 90% by volume distils up to 160°. Sodium nitrite to one-tenth of the weight of crude anthracene taken is dissolved in 10 times its weight of water, and sufficient 10% sulphuric acid (7-2 gms. for each 1 gm. of 10% nitrite) to decompose this quantity of nitrite is added to the benzol—anthracene mixture and the temperature maintained at 25°. The nitrite solution is then run in at such a speed that no red fumes escape. When all the solution has been added the mixture is filtered at the pump. The filtrate consists of two layers, one of sodium sulphate solution and one of solvent naphtha, or benzol containing the impurities such as nitroso-carbazol. The purified anthracene on the filter is washed with benzol or solvent naphtha this latter on a large scale is used for the final treatment of a fresh lot of crude anthracene. The initial benzol or solvent naphtha, after separation from the aqueous solution, is recovered by distillation. The anthracene from this treatment will be about 80% pure. It may be purified to 95% by crystallising from heavy bases (pyridine, etc.), and is finally raised by sublimation and re-crystallisation from benzol to 98%. (For the estimation of purity, see p. 497.) (C. T., 23, 8, 21 D.R.P., 122852.)... 

Alizarine red (S marks), Erweco alizarine acid red, alizarine orange S W, alizarine cyanine, brilliant alizarine cyanine, anthracene blue (S Marks), acid alizarine blue, alizarine dark green W, alizarine blue (S Marks), alizarine green A alizarine black S, alizarine indigo blue (S Marksl, coeruleine (S Marks). 0 n the addition of a few drops of dilute caustic soda (1 20), the colour becomes more 1 intense, and bluer ... 

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