OXYGEN INITIATED COMBUSTION - THERMOCHEMISTRY AND KINETICS OF UNSATURATED-HYDROCARBONS

The thermochemistry and kinetics of the initiation reactions involved in the oxidation of unsaturated fuels are explored. The thermochemistr y of intermediate radicals, diradicals, and molecular species involved are estimated using group additivity with some assistance from bond a dditivity. Kinetic parameters are estimated with the techniques of the rmochemical kinetics. In the case of acetylene, estimated rate constan ts are in excellent agreement with experimental results on the inducti on period and name speed, It is shown that the route initiated by O-2 addition to an unsaturated carbon atom to produce a 1,4 diradical is f aster than any other path available to form radicals capable of propag ating a chain. The 1,4 diradicals so produced can generally cyclize to form a dioxetane which exothermically opens to a dialdehyde which is the ultimate radical source. Below 1000 K unsaturates will always init iate oxidation faster than saturated fuels. (C) 1996 John Wiley & Sons , inc.