Reaction of sodium with carbazole, fluorene, and dibenzothiophene in a simulated crude phenanthrene results in their simultaneous removal also (runs 4, 5 ) . Mass-spectrometric analyses for these impurities showed that their maximum possible concentrations in all purified phenanthrenes was 0.02%. Because this was the highest sensitivity attainable by this analytical method, we cannot say whether treatment with sodium is more efficient in removing fluorene and carbazole than azeotropic distillation using diethylene glycol (7), but it is simpler. Reaction between sodium and anthracene is almost always discussed in terms of ether and amine solvents as reaction media (6, 12). Recently, however, reaction between vacuum-deposited sodium and a solution of anthracene in carefully purified toluene or octane a t room temperature has been reported ( I ) . Phenanthrene did not react with sodium under these conditions. Because the phenanthrene used by these workers probably contained the same impurities as their anthracene, we can assume the reaction described is between sodium and anthracene and not any impurities present. Sodium also reacts with anthracene at room temperature when these two compounds are suspended in dried xylene and ground in a ball mill ( 5 ) . Thus, from the data in Table I it may be assumed that, at temperatures near 200’ C., sodium reacts with anthracene (in molten phenanthrene) to form a sodioanthracene having a low volatility; the phenanthrene can then be distilled
sway, essentially free from anthracene. Phenanthrene, thus purified, can be prepared with anthracene contents
