| Title:  Alizarine Blue CAS Registry Number:  568-02-5 CAS Name:  5,6-Dihydroxynaphtho[2,3-f]quinoline-7,12-dione Additional Names:  7,8-dihydroxy-5,6-phthalylquinoline;  Alizarin Blue R;  C.I. 67410 Molecular Formula:  C17H9NO4 Molecular Weight:  291.26 Percent Composition:  C 70.10%, H 3.11%, N 4.81%, O 21.97% Literature References:  Prepn from 3-nitroalizarin, glycerol, and concd sulfuric acid:  Auerbach, J. Chem. Soc. 35, 799 (1879); Colour Index vol. 4 (3rd ed., 1971) p 4567. Properties:  Lustrous brownish violet needles from benzene, mp 268-270°.  Practically insol in water; sparingly sol in alc, ether; slightly sol in cold benzene; sol in amyl alcohol, glacial acetic acid, hot benzene. Melting point:  mp 268-270° Use:  As indicator in saturated alcoholic soln.  pH:  pink 0.0 to yellow 1.6; yellow 6.0 to green 7.6.  |