Absolute rate constant for the reaction of atomic chlorine with hydrogen peroxide vapor over the temperature range 265–400 K

Rate constants for the reaction of atomic chlorine with hydrogen peroxide have been measured from 265 to 400 K using the flash photolysis–resonance fluorescence technique. Analytical techniques were developed to measure [H2O2] under reaction conditions. Due to ambiguity in the interpretation of the analytical results, the data combine to give two equally acceptable representations of the temperature dependence: k1= (3.14±0.56) ×10−13 cm3 molecule−1 s−1 independent of temperature or k1= (1.24±0.74) ×10−12 exp(−384±168/T)cm3 molecule−1 s−1. The results are compared to previous work at 298 K and are theoretically discussed in terms of the mechanism of the reaction. Additional experiments on the H+H2O2 reaction at 298 and 359 K are compared with earlier results from this laboratory and give a slightly revised bimolecular rate constant of (4.89±0.70) ×10−12 exp(−2780±280/RT) cm3 molecule−1 s−1.