Kinetics of the gas-phase reactions of NO_3 radicals with ethyl acrylate, n-butyl acrylate, methyl methacrylate and ethyl methacrylate

摘要

The relative rate method has been used to determine the rate constants for the gas-phase reactions of NO_3 radicals with a series of acrylate esters: ethyl acrylate (k_1), n-butyl acrylate (k_2). methyl methacrylate (k_3) and ethyl methacrylate (k_4) at 298 ± 1 K and 760 Torr. The obtained rate constants are k_1= (1.8 ± 0.25) ×10~(-16) cm~3 molecule~(-1) s~(-1), k_2 = (2.1 ± 0.33) ×10~(-16) cm~3 molecule~(-1) s~(-1), k_3 = (3.6 ± 1.2)×10~(-15) cm~3 molecule~(-1) s~(-1), k_4 = (4.9 ± 1.7)×10~(-15) cm~3 molecule~(-1) s~(-1). The experimental rate constants are in good agreement with theoretical rate constants calculated by an algorithm of the correlation between the rate constants and the orbital energies for the reactions of unsaturated VOCs with NO_3 radicals. In addition, the atmospheric lifetimes of the compound against NO_3 attack are estimated and the results show that NO_3 reactions contribute little to the atmospheric losses of acrylate esters except in polluted regions.