Rate constants for the gas-phase reactions of nitrate radicals with geraniol, citronellol, and dihydromyrcenol

Abstract

Terpenes and terpene alcohols are prevalent compounds found in a wide variety of consumer products including soaps, flavorings, perfumes, and air fresheners used in the indoor environment. Knowing the reaction rate of these chemicals with the nitrate radical is an important factor in determining their fate indoors. In this study, the bimolecular rate constants of k NO 3 • +geraniol (16.6 ± 4.2) × 10 −12 , k NO 3 • +citronellol (12.1 ± 3) × 10 −12 , and k NO 3 • +dihydromyrcenol (2.3 ± 0.6) × 10 −14 cm 3 molecule −1 s −1 were measured using the relative rate technique for the reaction of the nitrate radical (NO 3 • ) with 2,6-dimethyl-2,6-octadien-8-ol (geraniol), 3,7-dimethyl-6-octen-1-ol (citronellol), and 2,6-dimethyl-7-octen-2-ol (dihydromyrcenol) at (297 ± 3) K and 1 atmosphere total pressure. Using the geraniol, citronellol, or dihydromyrcenol + NO 3 • rate constants reported here, pseudo-first-order rate lifetimes (k ) of 1.5, 1.1, and 0.002 h −1 were determined, respectively. C 2010 Wiley Periodicals, Inc. * Int J Chem Kinet 42: [669][670][671][672][673][674][675] 2010

Ultrafine particle emissions from essential-oil-based mosquito repellent products

“…Other low‐volatile compounds might be geraniol or citronellal degradation products with more functional groups (Hallquist et al., ). Reactions of these two compounds with ozone, OH, and NO 3 radicals are the possible ways of degradation (Forester and Wells, ; Forester et al., ; Harrison and Ham, ; Harrison et al., ; Nunes et al., ). Possible pathways/products and reaction rate constants were reported.…”

Volatile organic compound conversion by ozone, hydroxyl radicals, and nitrate radicals in residential indoor air: Magnitudes and impacts of oxidant sources

“…After formation, the NO 3 and remaining NO 2 are in equilibrium with dinitrogen pentoxide (N 2 O 5 ), which can also react with water to form nitric acid (HNO 3 ) indoors (Weschler et al, 1994). NO 3 /VOC reactions yield alkyl, alkoxy, and peroxy radicals, and stable carbonyls and oxygenated compounds that may contain organic nitrate groups (Ham, 2013; Harrison and Ham, 2010; Harrison and Wells, 2012; Jones and Ham, 2008). Organic nitrates are ‘under investigated’, but research on health effects and indoor NO x cycles have emphasized the need for more research (Carslaw, 2007; Carslaw et al, 2012).…”

“…Like OH, NO 3 is difficult to measure; however, modeling and inference experiments have estimated concentrations with an upper bound of ~10 −3 ppb (Nojgaard, 2010; Weschler et al, 2006). An average NO 3 /terpenoid reaction rate constant of ~10 3 ppb −1 h −1 suggests that NO 3 /terpenoid chemistry could impact indoor air (Flemmer and Ham, 2012; Ham, 2013; Harrison and Ham, 2010; Jones and Ham, 2008; Nazaroff and Weschler, 2004). …”

Kinetics and mechanism for OH-initiated gas-phase chemistry of α-terpineol

“…and also a prevalent VOC indoors, have received increasing attention. [12][13][14][15][16] Most of the terpenoids are reported to be present at signicant indoor concentrations. 17,18 Among them, 1-methyl-4isopropyl-1-cyclohexen-8-ol (a-terpineol, Scheme 1) is the main component of indoor cleaner emissions and pine oil, 17 as well as an emission from some molds existing in the indoor environment.…”