The near UV absorption cross-sections and the rate coefficients for the ozonolysis of a series of styrene-like compounds

The UV absorption cross-sections and the rate coefficients for the ozonolysis of styrene, alpha-methylstyrene, beta-methylstyrene, 2-methylstyrene and indene have been investigated. The absorption spectra were measured using a diode array spectrometer over the wavelength range 260-310 nm at 328 K. Large absorption cross-sections (similar to 10(-18) cm(2) molecule(-1)) were observed for the investigated compounds over the wavelength range 260-280 nm, while their absorption cross-sections decreased sharply above 290 nm with values of about 10(-20) to 10(-21) cm(2) molecule(-1) around 310 nm. The rate coefficients for the reactions of the aromatic compounds studied and O-3 measured in a simulation chamber using both absolute and relative methods at 295 +/- 3 K and atmospheric pressure were (in 10(-17) cm(3) molecule(-1) s(-1)): (1.5 +/- 0.3), (1.8 +/- 0.4), (3.1 +/- 0.6) and (16 +/- 4) for styrene, alpha-methylstyrene, 2-methylstyrene and indene, respectively. The data obtained were used to estimate the lifetimes of the investigated compounds. (C) 2007 Elsevier B.V. All rights reserved.