Kinetics of the gas‐phase reactions of NO 3 radicals with a series of aromatics at 296 ± 2 K

Rate constants have been determined at 296 ± 2 K for the gas phase reaction of NO 3 radicals with a series of aromatics using a relative rate technique. The rate constants obtained (in cm 3 molecule −1 s −1 units) were: benzene, <2.3 × 10 −17 ; toluene, (1.8 ± 1.0) × 10 −17 ; o xylene, (1.1 ± 0.5) × 10 −16 ; m xylene, (7.1 ± 3.4) × 10 −17 ; p xylene, (1.4 ± 0.6) × 10 −16 ; 1,2,3‐trimethylbenzene, (5,6 ± 2.6) × 10 −16 ; 1,2,4‐trimethylbenzene (5.4 ‐ 2.5) × 10 −16 ; 1,3,5‐trimethylbenzene, (2.4 ± 1.1) × 10 −16 ; phenol, (2.1 ± 0.5) × 10 −12 ; methoxybenzene, (5.0 ± 2.8) × 10 −17 ; o ‐cresol, (1.20 ± 0.34) × 10 −11 ; m ‐cresol, (9.2 ± 2.4) × 10 −12 ; p ‐cresol, (1.27 ± 0.36) × 10 −11 ; and benzaldehyde, (1.13 ± 0.25) × 10 −15 . These kinetic data, together with, in the case of phenol, product data, suggest that these reactions proceed via H‐atom abstraction from the substituent groups. The magnitude of the rate constants for the hydroxy‐substituted aromatics indicates that the nighttime reaction of NO 3 radicals with these aromatics can be an important loss process for both NO 3 radicals and these organics, as well as being a possible source of nitric acid, a key component of acid deposition.