Rate constant for the reaction of atomic chlorine with formaldehyde from 200 to 500 K

The absolute rate constant for the reaction of atomic chlorine with formaldehyde has been measured from 200 to 500 K using the flash photolysis–resonance fluoresence technique. The results were independent of substantial variations in [H2CO], total pressure (Ar) and flash intensity (i.e., initial [Cl]). The rate constant was shown to be invariant with temperature, the best representation for this temperature range being k1= (7.48±0.50) ×10−11 cm3 molecule−1 s−1, where the error is one standard deviation. This result is compared with the only previous determination of k1, which was a relative value obtained at 298 K. The rate constant is theoretically discussed and the potential importance of the reaction in stratospheric chemistry is considered.