Investigation of anthracene derivatives

Summary

• 1. Measurements have been made of the rate of the reaction between anthracene (9,10-dichloroanthracene) in aqueous suspension and chlorine at 2–3° and at 15–16°, using chlorine concentrations of 0.01 N and 0.05 N. The oxidation by chlorine of anthracene in aqueous suspension proceeds as a first-order reaction with respect to active chlorine. The reaction rate increases with increase in the concentration of active chlorine and is reduced by the hydrochloric acid that is formed; it is expressed by the equation:

  $$ - \frac{{d[Cl_2 ]}}{{dt}} = k'_2 \frac{{[Cl_2 ]}}{{[HCl]}}$$

• 2. It has been shown that the rate of oxidation of anthracene by chlorine water falls sharply towards the end owing to the formation of 9,10-dichloroanthracene, for the rate of the oxidation of the latter is many times less than the rate of the anthracene reaction.

• 3. The products of the oxidation of anthracene by aqueous chlorine at 15–16° for 60 hr have been isolated and identified. They are: anthraquinone (62%), 9,10-dihydroxyanthracene and oxanthranol (7%), 9-hydroxyanthracene (3%), 9,10-dichloroanthracene (12%), and unchanged anthracene (13%).

• 4. The mechanism of the oxidation of anthracene by aqueous chlorine has been indicated.

• 5. Measurements have been made of the rate of oxidation of anthracene and of 9,10-dichloroanthracene by the oxidizing agents: K₂Cr₂O₇ + H₂SO₄aq and KMnO₄ + KOnaq.

It has been shown: 1) that the rate of oxidation of anthracene, both in acid and in alkaline solution, is many times higher than the rate of oxidation of 9,10-dichloroanthracene, and 2)_that the rate of oxidation in alkaline medium is 4 to 5 times higher than in acid medium in the case of anthracen and is 60 to 80 times higher in the case of 9,10-dichloroanthracene.