Thermal decomposition of C3-substituted peroxyacyl nitrates

The gas phase thermal decomposition rates of C₃-substituted peroxyacyl nitrates, RC(O)OONO₂ have been measured at ambient temperature (287–298 K) and 1 atm. of air. Two saturated compounds (PnBN, R = n-C₃H₇- and PiBN, R = i-C₃H₇-) and two unsaturated compounds (MPAN, R = CH₂=C(CH₃)- and CPAN, R = CH₃CH=CH-) have been studied. In the narrow temperature range studied, thermal decomposition rates for PiBN, PnBN and MPAN exhibited linear Arrhenius behavior with, in units of 10^-4 s^-1, and at 298 K, k = 2.2 for PiBN, 2.3 for MPAN, and 2.7 for PnBN. The thermal decomposition rate of CPAN was 1.6 x 10^-4 s^-1 at 291.6 K and 1.73 x 10^-4 s^-1 at 293.2 K. These thermal decomposition rates are of the same magnitude as that for PAN, R = CH₃. Implications for the atmospheric persistence of C₃- substituted peroxyacyl nitrates are briefly discussed.