Atmospheric Chemistry of HFC-272ca: Spectrokinetic Investigation of the CH3CF2CH2O2 Radical, Its Reactions with NO and NO2, and the Fate of the CH3CF2CH2O Radical

Article abstract of DOI:10.1021/j100007a033

A pulse radiolysis technique has been used to investigate the UV absorption spectrum of the CH3CF2CH2O2 radical from HFC-272ca, CH3CF2CH3.The absorption cross sections were quantified in the wavelength range 220-320 nm; at 250 nm the absorption cross section for CH3CF3CH2O2 was δ=(451+/-59) x 1E-20 cm² molecule^-1.By following the increase in NO2 at 400 nm, the rate constant for the reaction of CH3CF2CH2O2 with NO was determined to be (8.5+/-1.9) x 1E-12 cm³ molecule^-1 s^-1.The reaction of CH3CF2CH2O2 with NO2 was found to have a reaction rate constant of (6.8+/-0.5) x 1E-12 cm³ molecule^-1 s^-1.The kinetics of the reaction of CH3CF2CH3 with F atoms and CH3CF2CH2 with O2 were studied.The rate constants were (2.8+/-0.9) x 1E-11 and (1.10+/-0.03) x 1E-12 cm³ molecule^-1 s^-1, respectively.The observed rate constant for the self-reaction of CH3CF2CH2O2 radicals was (8.6+/-)0.4) x 1E-12 cm³ molecule^-1 s^-1.The reaction of CH3CF2CH2O2 radicals with NO gives CH3CF2CH2O radicals; the dominant atmospheric fate of CH3CF2CH2O radicals is reaction with O2 to give CH3CF2CHO.As part of the present work, relative rate techniques were used to measure rate constant at 296+/-2 K for reactions of Cl and F atoms with CH3CF2CH3, with the values being (1.7+/-0.2) x 1E-14 and (3.3+/-0.8) x 1E-11 cm³ molecule^-1 s^-1, respectively.