Impurities were analyzed by gas chromatography to be <25 ppm.

The rate constant for the reaction of ClO with HO2, k1, was measured over the temperature range 235⩽T⩽393 K using laser magnetic resonance detection to monitor directly the concentrations of both reactants. Measurements were made at low pressures, 0.8⩽P⩽3.4 Torr, in three different discharge-flow tubes, 14.0, 25.4, and 36.7 mm i.d., and with two different sources for ClO radicals, Cl+O3 and Cl+Cl2O. The observed temperature dependence is fitted by the expression, k1=3.3×10−11 exp(−850/T)+4.5×10−12 (T/300)−3.7 cm3 molecule−1 s−1 The products of the reaction were not detected but the possible channels HOCl+O2 and HCl+O3 have important implications for stratospheric chemistry.

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Rate constants for reaction of the OH radical with CH3SH and CH3NH2 were determined over the temperature range 299–426 °K by a flash photolysis–resonance fluorescence technique. The Arrhenius expressions obtained were k (CH3SH) =8.89×10−12e(790±300)/RT cm3 molecule−1 sec−1 and k (CH3NH2) =1.02×10−11e(455±300)/RT cm3 molecule−1 sec−1, with rate constants at room temperature of (3.39±0.34) ×10−11 and (2.20±0.22) ×10−11 cm3 molecule−1 sec−1 for CH3SH and CH3NH2, respectively.

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