Title: Alizarine Orange

CAS Registry Number: 568-93-4

CAS Name: 1,2-Dihydroxy-3-nitro-9,10-anthracenedione

Additional Names: 1,2-dihydroxy-3-nitroanthraquinone; 3-nitroalizarin; C.I. Mordant Orange 14; C.I. 58015

Molecular Formula: C14H7NO6

Molecular Weight: 285.21

Percent Composition: C 58.96%, H 2.47%, N 4.91%, O 33.66%

Literature References: From 3-bromoalizarin in acetic acid with nitric acid: Barnett, Cook, J. Chem. Soc. 121, 1376 (1922). Additional prepns: Colour Index vol. 4 (3rd ed., 1971) p 4514.

Properties: Orange needles or plates from acetic acid, dec 244°. Sublimes with partial decompn. Yellow in organic solvents, purple-red in dil aq alkali, orange in H2SO4.

Use: Dyes cloth mordanted with Al orange, with Fe red to violet. As indicator in satd alc soln. pH 2.0-4.0, color change from golden orange to flat yellow (in water). pH 5.0-6.5 from yellow to purplish red.