ANTHRACENE, CHRYSENE, THEIR NITRO-AND METHYL-DERIVATIVES PHOTOSTABILITY IN ISOOCTANE

Abstract

Kinetics of photodegradation, half lifes and photodegradation products of two parent polycyclic aromatic hydrocarbons (anthracene and chrysene), their methyl-derivatives (9-methylanthracene and 6-methylchrysene) and selected nitro-derivatives (9-nitroanthracene and 6-nitrochrysene) were observed during exposition to UV irradiation in isooctane solutions. Additionally, influence of substituent position on photostability of PAH methyl-derivatives was observed in isooctane solutions. 1-Methylanthracene, 2-methylanthracene, 9-methylanthracene and 1-methylchrysene, 2-methylchrysene, 3-methylchrysene, 4-methylchrysene, 5-methylchrysene, 6-methylchrysene were chosen for the experiment. It was found that the effect of substituent type on photodegradation was very significant, especially in the case of nitrated polycyclic aromatic hydrocarbons. Decomposition of nitro-derivatives was easier than degradation of corresponding parent polycyclic aromatic hydrocarbons. On the other hand stability of methyl-derivatives was slightly better in comparison with parent polycyclic aromatic hydrocarbons. The effect of methyl-group position was negligible. The most frequent photoproducts were quinones, benzoic acid and other derivatives with hydroxyl, carbonyl and carboxyl groups for all polycyclic aromatic hydrocarbons and the derivatives. Degradation intermediates underwent further oxidation, fragmentation or reduction.

Keywords:

• photodegradation
• photostability
• polycyclic aromatic hydrocarbons
• nitro-derivatives
• methyl-derivatives
• isooctane

This study was partly supported by Ministry of Agriculture of the Czech Republic (project MZE0002716201).