Rate Coefficients of the Reaction of OH with Allene and Propyne at High Temperatures.
Allene (H2C═C═CH2; a-C3H4) and propyne (CH3C≡CH; p-C3H4) are important species in various chemical environments. In combustion processes, the reactions of hydroxyl radicals with a-C3H4and p-C3H4are critical in the overall fuel oxidation system. In this work, rate coefficients of OH radicals with allene (OH + H2C═C═CH2→ products) and propyne (OH + CH3C≡CH → products) were measured behind reflected shock waves over the temperature range of 843-1352 K and pressures near 1.5 atm. Hydroxyl radicals were generated by rapid thermal decomposition of tert-butyl hydroperoxide ((CH3)3-CO-OH), and monitored by narrow line width laser absorption of the well-characterized R1(5) electronic transition of the OH A-X (0,0) electronic system near 306.7 nm. Results show that allene reacts faster with OH radicals than propyne over the temperature range of this study. Measured rate coefficients can be expressed in Arrhenius form as follows: kallene+OH(T) = 8.51(±0.03) × 10-22T3.05exp(2215(±3)/T), T = 843-1352 K; kpropyne+OH(T) = 1.30(±0.07) × 10-21T3.01exp(1140(±6)/T), T = 846-1335 K.
Clean Combustion Research Centre, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia.|Laboratory for Thermal Processes & Combustion, Paul Scherrer Institute (PSI) , CH-5232 Villigen PSI, Switzerland.
Et-Touhami
ET
Es-Sebbar
Clean Combustion Research Centre, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia.
Fethi
F
Khaled
Clean Combustion Research Centre, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia.|Mechanical Engineering Department, Faculty of Engineering, Alexandria University , Alexandria 21544, Egypt.
Ahmed
A
Elwardany
Clean Combustion Research Centre, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia.
Aamir
A
Farooq