Thermal Decomposition of Quinoline and Isoquinoline. The Role of 1-Indene Imine Radical

The thermal reactions of quinoline and isoquinoline were studied behind reflected shock waves in a pressurized driver single pulse shock tube over the temperature range 1275−1700 K and densities of ∼3 × 10 -5 mol/cm 3 . The decomposition products found in the postshock mixtures of quinoline and isoquinoline and their production rates were identical for both isomers. They were C 2 H 2, C 6 H 5 CN, HC⋮CCN, C 6 H 6, HCN, C 6 H 5 −C⋮CH, and C 4 H 2 . Trace quantities of C 6 H 4, C 5 H 5 N and C 5 H 4 N−C⋮CH were also found. The total disappearance rates of quinoline and isoquinoline are the same, and in terms of a first-order rate constant they are given by k total = 10 13.0 exp(−75.5 × 10 3 / RT ) s -1 where R is expressed in units of cal/(K mol). The same product distribution in the two isomers can be accounted for if the production of 1-indene imine radical as an intermediate is assumed. A kinetic scheme containing the reactions of both quinoline and isoquinoline with 72 species and 148 elementary reactions accounts for the observed product distribution. The reaction scheme is given, and the results of computer simulation and sensitivity analysis are shown.