Site-specific reaction rate constant measurements for various secondary and tertiary H-abstraction by OH radicals (original) (raw)

2015, Combustion and Flame

Reaction rate constants for nine site-specific hydrogen atom (H) abstraction by hydroxyl radicals (OH) have been determined using experimental measurements of the rate constants of Alkane + OH ? Products reactions. Seven secondary (S 20 , S 21 , S 22 , S 30 , S 31 , S 32 , and S 33 ) and two tertiary (T 100 and T 101 ) site-specific rate constants, where the subscripts refer to the number of carbon atoms (C) connected to the next-nearest-neighbor (N-N-N) C atom, were obtained for a wide temperature range (250-1450 K). This was done by measuring the reaction rate constants for H abstraction by OH from a series of carefully selected large branched alkanes. The rate constant of OH with four different alkanes, namely 2,2-dimethyl-pentane, 2,4-dimethyl-pentane, 2,2,4-trimethyl-pentane (iso-octane), and 2,2,4,4-tetramethyl-pentane were measured at high temperatures (822-1367 K) using a shock tube and OH absorption diagnostic. Hydroxyl radicals were detected using the narrow-line-width ring-dye laser absorption of the R 1 (5) transition of OH spectrum near 306.69 nm.