Date on Master's Thesis/Doctoral Dissertation
Acridine was discovered by Graebe and Caro who found that it accompanied the crude anthracene obtained from coal-tar. For its isolation, the portion of the tar distilling at 300°- 360° C. was extracted by dilute sulphuric acid and precipitated by potassium dichromate, the precipitate recrystallized from hot water and then decomposed by dilute ammonia. The free base was then dissolved in hot hydrochloric acid, from this solution acridine hydrochloride was thrown out by addition of an excess of concentrated hydrochloric acid. From this salt the free acridine was liberated by ammonia.
Vianna, Altemiro Ferreira, "Acridine and its derivatives." (1926). Electronic Theses and Dissertations. Paper 1491.