Flash Photolysis Studies of Free-Radical Reactions: C3H5 + C3H5 (293-691 K) and C3H5 + NO (295-400 K)

Article abstract of DOI:10.1021/j100216a021

A laser flash photolysis system, capable of producing kinetic data of high precision, is described and detailed consideration is given to the methods of data analysis.Measurements of the allyl radical recombination reaction at the high-pressure limit show that the rate constant decreases slightly with temperature and may be described by the Arrhenius parameters A=(1.69+-0.03)xE-11 cm³ molecule^-1 s^-1 and E_a=-(1.1+-0.1) kJ mol^-1, over the temperature range 293-571 K, if van den Bergh and Callear's absorption cross section is employed and assumed independent of temperature.The errors quoted refer to one standard deviation and do not include the error in the absorption cross section.The raction between C3H5 and NO is also studied, over the temperature range 295-400 K, and is found to be pressure dependent.The limiting high-pressure rate constant decreases with temperature, with a negative activation energy of -(3.4+-0.1) kJ mol^-1.