Web Release Date: August 10,
Atmospheric Lifetimes and Fates of Selected Fragrance Materials and Volatile Model Compounds
and
Interdepartmental Graduate Program in Environmental Toxicology and Department of Environmental Sciences, Department of Chemistry, and Air Pollution Research Center, University of California, Riverside, California 92521, and The Procter & Gamble Company, 11530 Reed Hartman Highway, Cincinnati, Ohio 45241
Received for review February 27, 2001
Revised manuscript received June 5, 2001
Accepted June 25, 2001
Abstract:
Fragrance materials are semivolatile organic compounds
widely used in consumer products. Despite their generally
low volatility, it is expected that a fraction of these
compounds will volatilize into the atmosphere, where they
can photolyze, react with OH radicals, NO3 radicals and
O3, and/or undergo wet and dry deposition. Using relative
rate methods, rate constants have been measured at
296 ± 2 K for the gas-phase reactions of OH radicals, NO3
radicals, and O3 with the fragrance materials 1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthalenyl)ethanone
(OTNE), acetyl cedrene [(3R-(3a,3ab,7b,8aa))-1-(2,3,4,7,8,8a-hexahydro-3,6,8,8-tetramethyl-1H-3a,7-methanoazulen-5-yl)ethan-1-one], and HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethycyclopenta-[
]-2-benzopyran) as well
as with isochroman which is structurally related to
HHCB. Measured rate constants (in cm3 molecule-1 s-1
units) are OH radical reactions [OTNE, (9.85 ± 0.88) × 10-11;
acetyl cedrene, (7.7 ± 1.6) × 10-11; HHCB, (2.6 ± 0.6) ×
10-11; and isochroman, (3.7 ± 0.6) × 10-11], NO3 radical
reactions [OTNE, (1.71 ± 0.19) × 10-11 and acetyl cedrene,
(4.1 ± 1.0) × 10-15], and O3 reactions [OTNE, (2.1 ± 0.5)
× 10-18 and acetyl cedrene, <2.2 × 10-18] where the error
limits are two least-squares standard deviations. Rate
constants for the OH radical reactions predicted by a
structure-reactivity estimation method agree well with the
measured values. The dominant tropospheric loss
processes for the compounds studied are calculated to
be in a reaction with OH radicals during daytime and, for
OTNE and acetyl cedrene, with NO3 radicals during
nighttime. The calculated atmospheric lifetimes due to
daytime reaction with the OH radical are a few hours or
less for the fragrance materials studied and indicate that
these specific compounds will not undergo long-range
transport in the atmosphere.
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