Kinetics of the Hydrogen Abstraction C2H3• + Alkane → C2H4 + Alkyl Radical Reaction Class

This paper presents an application of the reaction class transition state theory (RC-TST) to predict thermal rate constants for hydrogen abstraction reactions of the type C2H3 + alkane -> C2H4 + alkyl radical. The linear energy relationship (LER) was proven to hold for both noncyclic and cyclic hydrocarbons. We have derived all parameters for the RC-TST method front rate constants of 19 representative reactions, coupling with LER and the barrier height grouping (BHG) approach. Both the RC-TST/LER, where only reaction energy is needed, and the RC-TST/BHG, where no other information is needed, can predict rate constants for any reaction in this reaction class with satisfactory accuracy for combustion modeling. Our analysis indicates that less than 90% systematic errors on the average exist in the predicted rate constants using the RC-TST/LER or RC-TST/BHG method, while in comparison to explicit rate calculations, the differences are within a factor of 2 on the average.