ORANGE I

Химические свойства

Crystalline

Подготовка

4-Aminobenzenesulfonic acid diazo, and Naphthalen-1-ol?coupling.

Методы очистки

Purify the dye by dissolving it in the minimum volume of H2O, adding, with stirring, a large excess of EtOH. The salt separates as orange needles. It is collected by centrifugation or filtration, washed with absolute EtOH (3x) and Et2O (2x) in the same way and dried in a vacuum desiccator over KOH. The free acid can be recrystallised from EtOH. [Slotta & Franke Chem Ber 64 86 1931, Beilstein 16 H 275, 16 II 117, 16 IV 410.] The purity can be checked by titration with titanium chloride [Klotz J Am Chem Soc 68 2299 1946].