Experimental Studies of Gas Phase Reactions Using the Turbulent Flow Tube Technique

This thesis describes the development and implementation of the turbulent flow tube technique, a new method for studying gas phase reaction kinetics. The plausibility of the turbulent flow tube technique has been examined using a numerical model. Several experimental studies of key fluid dynamical processes have also been performed. These experiments include flow visualization of reactant mixing, pitot tube measurements of velocity profiles, reactant wall loss measurements, and pulsed tracer studies. The validity of the turbulent flow tube technique has been verified by determining the rate constants of several well characterized reactions. The reactions studied are H + 03 --> OH + 02, H + C12 HCI + C1, Cl + NO2 -> ClNO 2 , C + CH 4 -> HC + CH 3, and Cl + 03 -> C1O + 02. The turbulent flow tube technique has also been used to measure the reaction rate constants of two reactions of the hydroxyl radical which are believed to play an important role in atmospheric chemistry: OH + HNO3 H2 0 + NO3 and OH + H20 2 -> H2 0 + HO2. The rate constants for both of these reaction have been measured over a wide range of pressures and temperatures. Finally, a high pressure ionizing mass spectrometer has been developed which will ultimately be used as a detection technique in a turbulent flow tube system. Thesis Supervisor: Dr. Mario J. Molina Title: Martin Professor of Environmental Chemistry