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Smog chambers interfaced with in situ FT-IR detection were used to investigate the kinetics and mechanisms of the Cl atom, OH radical, and O 3 initiated oxidation of ( Z )- and ( E )-1,2-dichloroethene (CHClCHCl) under atmospheric conditions. Relative and absolute rate methods were used to measure k (Cl + ( Z )-CHClCHCl) = (8.80 ± 1.75) × 10 -11 , k (Cl + ( E )-CHClCHCl) = (8.51 ± 1.69) × 10 -11 , k (OH + ( Z )-CHClCHCl) = (2.02 ± 0.43) × 10 -12 , k (OH + ( E )-CHClCHCl) = (1.94 ± 0.43) × 10 -12 , k (O 3 + ( Z )-CHClCHCl) = (4.50 ± 0.45) × 10 -21 , and k (O 3 + ( E )-CHClCHCl) = (1.02 ± 0.10) × 10 -19 cm 3 molecule -1 s -1 in 700 Torr of N 2 /air diluent at 298 ± 2 K. Pressure dependencies for the Cl atom reaction kinetics were observed for both isomers, consistent with isomerization occurring via Cl atom elimination from the chemically activated CHCl-CHCl-Cl adduct. The observed products from Cl initiated oxidation were HC(O)Cl (117-133%), CHCl 2 CHO (29-30%), and the corresponding CHClCHCl isomer (11-20%). OH radical initiated oxidation gives HC(O)Cl as a major product. For reaction of OH with ( E )-CHClCHCl, ( Z )-CHClCHCl was also observed as a product. A significant chlorine atom elimination channel was observed experimentally (HCl yield) and supported by computational results. Photochemical ozone creation potentials of 12 and 11 were estimated for ( Z )- and ( E )-CHClCHCl, respectively. Finally, an empirical kinetic relationship is explored for the addition of OH radicals or Cl atoms to small alkenes. The results are discussed in the context of the atmospheric chemistry of ( Z )- and ( E )-CHClCHCl.

An investigation of CCl3COCl was conducted with the purpose of using the compound as an alternative Cl atom precursor in laboratory settings. CCl3COCl can be used with or without O2 as a source of Cl atoms and photolysis studies in air and N2 diluent displayed COCl2 and CO as being the major photolysis products. Relative rate studies were performed to determine the Cl atom rate coefficients for reaction with CH3Cl and C2H2 and the results were in agreement with literature values. Cl atom rate coefficients for reaction with n-CH2[double bond, length as m-dash]CH(CH2)3CN and n-CH2[double bond, length as m-dash]CH(CH2)4CN were determined as (2.95 ± 0.58) × 10-10 and (3.73 ± 0.60) × 10-10 cm3 molecule-1 s-1, respectively. CCl3COCl requires UV-C irradiation, so not all molecules are feasible for use in e.g. relative rate studies. Furthermore, it is recommended to perform experiments with O2 present, as this minimizes IR feature disturbance from product formation.

Smog chamber/FTIR techniques were used to investigate the kinetics and mechanism of the Cl atom and OH radical initiated oxidation of 2,2-dichloroethanol at (296 ± 1) K. Relative rate methods were used to measure k(Cl + CHCl 2 CH 2 OH) = (5.87 ± 0.96) × 10 -12 and k(OH + CHCl 2 CH 2 OH) = (5.54 ± 1.94) × 10 -13 cm 3 molecule -1 s -1 . Chlorine atom initiated oxidation of CHCl 2 CH 2 OH in one atmosphere of air gives HCOCl, CHCl 2 CHO, and COCl 2 in yields of (62 ± 5)%, (39 ± 10)%, and (8 ± 2)%, respectively. The rate constant k(Cl + CHCl 2 CHO) = (8.3 ± 16) × 10 -12 cm 3 molecule -1 s -1 was determined and the IR spectra of CHCl 2 CHO is reported for the first time. The atmospheric lifetime for CHCl 2 CH 2 OH is estimated as 21 days. The experimental results are discussed in the context of the atmospheric chemistry of chlorinated alcohols.

Fourier transform infrared smog chamber techniques were used to study the kinetics and mechanisms of the reactions of Cl atoms and OH radicals with pentafluorophenol (C 6 F 5 OH) in 700 Torr total pressure of air or N 2 diluent at 296 ± 2 K. Rate constants k (OH + C 6 F 5 OH) = (6.88 ± 1.37) × 10 -12 cm 3 molecule -1 s -1 and k (Cl + C 6 F 5 OH) = (2.52 ± 0.31) × 10 -11 cm 3 s -1 molecule -1 in 700 Torr air diluent were determined. In 700 Torr N 2 , the rate constant for the reaction of C 6 F 5 OH with Cl atoms is linearly dependent on the Cl atom concentration. Product studies on this reaction in both 700 Torr air and 700 Torr N 2 diluent show the formation of nonconjugated products. The photolysis constant of C 6 F 5 OH was determined by 254 nm UV irradiation of a C 6 F 5 OH and CH 3 CHO mixture in 700 Torr air or N 2 at 296 ± 2 K and yielded a photolysis rate constant of J (C 6 F 5 OH) = (2.83 ± 0.25) × 10 -3 s -1 . Results are discussed with respect to the atmospheric chemistry of other halogenated aromatic species.

Smog chamber/Fourier transform infrared (FTIR) techniques were used to measure the kinetics of the reaction of n-CH 2 ═CH(CH 2 ) x CN ( x = 0-4) with Cl atoms, OH radicals, and O 3 : k(CH 2 ═CHCN + Cl) = (1.03 ± 0.13) × 10 -10 , k(CH 2 ═CHCH 2 CN + Cl) = (2.02 ± 0.35) × 10 -10 , k(CH 2 ═CH(CH 2 ) 2 CN + Cl) = (2.75 ± 0.45) × 10 -10 , k(CH 2 ═CHCN + OH) = (4.21 ± 0.95) × 10 -12 , k(CH 2 ═CHCH 2 CN + OH) = (1.55 ± 0.34) × 10 -11 , k(CH 2 ═CH(CH 2 ) 2 CN + OH) = (2.98 ± 0.64) × 10 -11 , k(CH 2 ═CH(CH 2 ) 3 CN + OH) = (3.34 ± 0.64) × 10 -11 , k(CH 2 ═CH(CH 2 ) 4 CN + OH) = (3.61 ± 0.85) × 10 -11 , k(CH 2 ═CHCN + O 3 ) = (2.55 ± 0.28) × 10 -20 , k(CH 2 ═CHCH 2 CN + O 3 ) = (1.17 ± 0.24) × 10 -18 , k(CH 2 ═CH(CH 2 ) 2 CN + O 3 ) = (3.35 ± 0.69) × 10 -18 , k(CH 2 ═CH(CH 2 ) 3 CN + O 3 ) = (4.07 ± 0.82) × 10 -18 , and k(CH 2 ═CH(CH 2 ) 4 CN + O 3 ) = (7.13 ± 1.49) × 10 -18 cm 3 molecule -1 s -1 at a total pressure of 700 Torr of air or N 2 diluents at 296 ± 2 K. CH 2 ClC(O)CN, HC(O)CN, HC(O)Cl, HCN, NCC(O)OONO 2 , and ClC(O)OONO 2 were identified as products from the Cl initiated oxidation of CH 2 ═CHCN. The product spectra were compared to experimental and theoretically calculated IR spectra. No products could be determined from the oxidation of n-CH 2 ═CH(CH 2 ) x CN ( x = 1-4). With the determined OH rate constants, the atmospheric lifetimes for n-CH 2 ═CH(CH 2 ) x CN ( x = 0-4) were estimated to be 66, 18, 9.3, 8.3, and 7.7 h, respectively. It was found that these unsaturated nitriles have no significant atmospheric environmental impact.