Dyes cloth mordanted with Al orange, with Fe red to violet. As indicator in satd alcohol solution. 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.
?? ??
(a) in the presence of boric acid 1,2-Dihydroxyanthracene-9,10-dionein sulfuric acid in the nitration; (b) 1,2-Dihydroxyanthracene-9,10-dionein glacial acetic acid, toluene, petroleum ether or the nitration of nitrobenzene.
Purification Methods
Crystallise the dye from AcOH (m 244-245o). It has max at 494nm (H2SO4) and forms Cu salts. [Beilstein 8 H 447, 8 II 491, 8 III 3774, 8 IV 2359.]
