Title: Eriochrome® Black T (Ciba)
CAS Registry Number: 1787-61-7
CAS Name: 3-Hydroxy-4-[(1-hydroxy-2-naphthalenyl)azo]-7-nitro-1-naphthalenesulfonic acid monosodium salt
Additional Names: C.I. Mordant Black 11; C.I. 14645
Molecular Formula: C20H12N3NaO7S
Molecular Weight: 461.38
Percent Composition: C 52.06%, H 2.62%, N 9.11%, Na 4.98%, O 24.27%, S 6.95%
Literature References: Prepn: Hagenbach, US 790363 (1904 to Geigy); Colour Index vol. 4 (3rd ed., 1971) p 4067.
Properties: Brownish-black powder with a faint metallic sheen. Sol in hot water giving a reddish-brown soln when cold. Violet-brown precipitate with excess HCl. Deep blue, then red in aq soln of NaOH. Sol in concd H2SO4 giving a blackish-blue soln which yields a brown precipitate on dilution.
Use: To dye wool from an acid bath reddish-black, which can be converted to blue-black by afterchroming. As indicator in the determination of the total calcium and magnesium content of water. |