Rufigallic acid

Alizarin may be prepared artificially by fusing dibromanthra-quinone, nitroanthraquinone, or anthraquinonesulphonic acid with potash or soda [3] also by condensation of phthalic acid with pyrocatechin [4], and by reduction of rufigallic acid [13]. Alizarin has only been prepared on an industrial scale from anthra-quinone, and the artificial product has practically displaced madder in the course of the last twenty years. 

Anthragallol has a brown colour, and dyes brown shades on alumina or chromic oxide. The commercial Alizarin Brown is a mixture of anthragallol with more or less rufigallic acid. 

Pierre Jean Robiquet (Rennes, 13 January 1780-Paris, 29 April 1840) was an apothecary and a professor in the Paris ficole superieure de Pharmacie. He discovered asparagine, glycyrrhizin in liquorice, narcotine, caffeine independently of Pelletier and Caventou (see p. 244), alizarin and purpurin in madder, orcinol in lichens, codeine, and rufigallic acid (hexahydro qran-thraquinone) by heating gallic acid with concentrated sulphuric acid. He investigated carbon disulphide, prepared pure baryta and nickel, investigated cantharides and kermes, and published fiirther papers on madder, orcin, and opium. 

Rufigallic acid 1,2,3,5,6,7 -hexa-hydroxyanthra-quinone 1835 Cl 58600 PJ Robiquet (1780-1840) Gallic acid - - H2SO4... 

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