Unimolecular decomposition of formic and acetic acids: A shock tube/laser absorption study

The rate constants for acetic acid decomposition were obtained by fitting simulated profiles, using an acetic acid pyrolysis mechanism, to the measured species time-histories. The branching ratio, k4/k3, was found to be approximately 2. The decarboxylation and dehydration reactions of acetic acid appear to be in the falloff region over the tested pressure range:k3(1atm)=3.18×1011exp(-28679/T)s-1(±30%)k3(6atm)=3.51×1012exp(-31330/T)s-1(±26%)k4(1atm)=7.9×1011exp(-29056/T)s-1(±34%)k4(6atm)=6.34×1012exp(-31330/T)s-1(±31%).