Gas-phase chemistry of (alpha-terpineol with ozone and OH radical: rate constants and products.
A bimolecular rate constant, kOH+alpha-terpineol, of (1.9 +/- 0.5) x 10(-10) cm3 molecule(-1) s(-1) was measured using gas chromatography/mass spectrometry and the relative rate technique for the reaction of the hydroxyl radical (OH) with alpha-terpineol (1-methyl-4-isopropyl-1-cyclohexen-8-ol) at (297 +/- 3) K and 1 atm total pressure. Additionally, a bimolecular rate constant, kO3+alpha-terpineol, of (3.0 +/- 0.2) x 10(-16) cm3 molecule(-1) s(-1) was measured by monitoring the first order decrease in ozone concentration as a function of excess alpha-terpineol. To better understand alpha-terpineol's gas-phase transformation in the indoor environment, the products of the alpha-terpineol + OH and alpha-terpineol + 03 reactions were also investigated. The positively identified alpha-terpineol/OH reaction products were acetone, ethanedial (glyoxal, HC(=O)C(=O)H), and 2-oxopropanal (methyl glyoxal, CH3C(=O)C(=O)H). The positively identified alpha-terpineol/O3 reaction product was 2-oxopropanal (methyl glyoxal, CH3C(=O)C(=O)H). The use of derivatizing agents O-(2,3,4,5,6-pentalfluorobenzyl)hydroxylamine (PFBHA) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) clearly indicated that several other reaction products were formed. The elucidation of these other reaction products was facilitated by mass spectrometry of the derivatized reaction products coupled with plausible alpha-terpineol/OH and alpha-terpineol/O3 reaction mechanisms based on previously published volatile organic compound/ OH and volatile organic compound/O3 gas-phase reaction mechanisms.
Wells
J R
JR
Exposure Assessment Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, 1095 Willowdale Road, Morgantown, West Virginia 26505, USA. ozw0@cdc.gov
D000393:Air Pollutants; D000081005:Cyclohexane Monoterpenes; D053138:Cyclohexenes; D004784:Environmental Monitoring / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D006859:Hydrogen / Q000032:analysis; D006878:Hydroxides / Q000032:analysis; D017665:Hydroxyl Radical / Q000032:analysis*; D006898:Hydroxylamines / Q000032:analysis; D007287:Inorganic Chemicals; D007700:Kinetics; D008956:Models, Chemical; D039821:Monoterpenes / Q000737:chemistry*; D016877:Oxidants / Q000032:analysis; D010091:Oximes / Q000032:analysis; D010126:Ozone / Q000737:chemistry*; D011312:Pressure; D011765:Pyruvaldehyde / Q000737:chemistry; D013696:Temperature; D013997:Time Factors; D014297:Trimethylsilyl Compounds / Q000032:analysis; D014481:United States; D005466:Fluorocarbons
D000393:Air Pollutants; D000081005:Cyclohexane Monoterpenes; D053138:Cyclohexenes; D006859:Hydrogen; D006878:Hydroxides; D017665:Hydroxyl Radical; D006898:Hydroxylamines; D007287:Inorganic Chemicals; D039821:Monoterpenes; D016877:Oxidants; D010091:Oximes; D010126:Ozone; D011765:Pyruvaldehyde; D014297:Trimethylsilyl Compounds; C016775:alpha-terpineol; C010277:Florox Reagent; D005466:Fluorocarbons; C047270:N,N-bis(trimethylsilyl)-2,2,2-trifluoroacetamide; C031356:hydroxide ion