Geraniol (2,6-dimethyl-2,6-octadien-8-ol) reactions with ozone and OH radical: Rate constants and gas-phase products

The bimolecular rate constants, kOH+geraniol, (231±58)×10−12 cm3 molecule−1 s−1 and kO3+geraniolkO3+geraniol, (9.3±2.3)×10−16 cm3 molecule−1 s−1, were measured using the relative rate technique for the reaction of the hydroxyl radical (OH) and ozone (O3) with 2,6-dimethyl-2,6-octadien-8-ol (geraniol) at (297±3) K and 1 atmosphere total pressure. To more clearly define part of geraniol's indoor environment degradation mechanism, the products of the geraniol+OH and geraniol+O3 reactions were also investigated. The identified geraniol+OH and geraniol+O3 reaction products were: acetone, hydroxyacetaldehyde (glycolaldehyde, HC(O)CH2OH), ethanedial (glyoxal, HC(O)C(O)H), and 2-oxopropanal (methylglyoxal, CH3C(O)C(O)H). The use of derivatizing agents O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) and N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) were used to propose 4-oxopentanal as the other major geraniol+OH and geraniol+O3 reaction product. The elucidation of this other reaction product was facilitated by mass spectrometry of the derivatized reaction products coupled with plausible geraniol+OH and geraniol+O3 reaction mechanisms based on previously published volatile organic compound+OH and volatile organic compound+O3 gas-phase reaction mechanisms.