Kinetics of the hydrogen abstraction R−OH + H → R• −OH + H2 reaction class: An application of the reaction class transition state theory

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 R-OH + H → R•-OH + H2. We have derived all parameters for the RC-TST method with linear energy relationships (LERs) and the barrier height grouping (BHG) approach for this reaction class from rate constants of 37 representative reactions divided in two types of hydrogen abstraction, namely from α carbon sites and non-α carbon sites two training sets. Error analyses indicate that the RC-TST/LER, where only reaction energy is needed, and 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. Specifically for this reaction class, the RC-TST/LER and RC-TST/BHG methods have, respectively, less than 40% and 90% systematic errors in the predicted rate constants, when compared to the explicit full TST/Eckart method. The branching ratio analysis shows that in the low-temperature regime α abstractions are dominant, whereas, for T > 1500 K, abstractions at other sites become more important. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 43: 78–98, 2011