Acid Alizarin Bordeaux

The fact that dihydroxyanthraquinones can be directly oxidised to higher phenols with fuming sulphuric acid is of technical importance. Alizarin and quinizarin yield in this way the same 1 2 5 8-tetra-hydroxyanthraquinone (alizarin bordeaux), which can be further oxidised to the important compound anthracene blue (1 2 4 5 6 8-hexa-hydroxyanthraquinone). This dye is obtained technically from 1 5-or 1 8-dinitroanthraquinone by means of a very interesting reaction,... 

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. 

If alizarin Bordeaux be dissolved in concentrated sulphuric acid and treated with manganese peroxide or arsenic acid, oxidation takes place, a pentoxyanthraquinone being formed —... 

Alizarine blue may be oxidised by action of fuming sulphuric acid, the process being analogous to that used for the preparation of Alizarin, Bordeaux. At 50° to 60° a dyestuff called Alizarin Blue-green is formed, and is best isolated in form of its bisulphite compound. It is a monosulphonic acid of mono-oxyalizarin blue. 

From alizarin there can be prepared, further, by nitration, the a- or /J-nitro-alizarin, and from this, by reduction, the corresponding amido-alizarin. From (i-nitro- and amido-alizariu, by heating with glycerol and sulphuric acid, the important Alizarin Blue is obtained. Further, by the action of fuming sulphuric add on alizarin there is obtained a tetraoxyanthraquinone (Bordeaux), etc. 

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