Shock tube measurements of the reaction rates of OH with ketones at high temperatures

Ketones are potential biofuel candidates and are also formed as intermediate products during the oxidation of large hydrocarbons or oxygenated fuels, such as alcohols and esters. This paper presents a shock tube study of the reaction rates of hydroxyl radicals (OH) with 2-butanone and 3-buten-2-one. The measurements were performed over the temperature range of 950 -1400 K near 1.5 atm. The OH profiles were monitored by the narrow-line-width ring-dye laser absorption of the well-characterized R₁(5) line in the OH A-X (0, 0) band near 306.69 nm. The measured reaction rate of 2-butanone with OH agreed well with the literature data, while we present the first high-temperature measurements for the reaction of OH with 3-buten-2-one. The following Arrhenius expressions are suggested over the temperature range of 950 -1450 K: K_c2H₅COCH₃+OH = 6.78× 10¹³exp(-2534/T)cm³mol^-1s^-1/K_c2H₃COCH₃+OH = 4.178× 10¹³exp(-2534/T)cm³mol^-1s^-1 The presence of the double bond in 3-buten-2-one causes the reaction rate constant with OH to show non-Arrhenius behavior and the rate increase as temperature decreases at lower temperatures.