4355. Gallocyanine

Nomenclature

CAS number: 1562-85-2
1-Carboxy-7-(dimethylamino)-3,4-dihydroxyphenoxazin-5-ium chloride; C.I. Mordant Blue 10; C.I. 51030.
C15H13ClN2O5; mol wt 336.73.
C 53.50%, H 3.89%, Cl 10.53%, N 8.32%, O 23.76%.

Description and references

Made by introducing nitrosodimethylaniline hydrochloride into a suspension of gallic acid in boiling methanol: Koechlin, DE 19580 (1881), Frdl. 1, 269; Nietzki, Otto, Ber. 21, 1740 (1888); Colour Index vol. 4 (3rd ed., 1971) p 4460.

Chemical structure

Properties

Green crystals. Practically insol in cold water. Slightly sol in hot water; sol in alcohol, glacial acetic acid, in alkali carbonates with reddish color, in concd HCl with a blue color which becomes red upon diluting with water.

Use

As a dye; in alkali carbonate soln as a reagent for lead with which it forms a deep violet color.