Research

Arthur Fontijn

HIGH-TEMPERATURE REACTION KINETICS LABORATORY

Our research deals with the chemistry of combustion, in many of its aspects.  Thus, the development of more efficient, less polluting, power generating combustors (e.g. turbines, car engines, and rocket motors), waste incinerators, fire extinguishers, etc. requires accurate chemical kinetic input data on individual reactions over large temperature ranges.  The Arrhenius equation is often not obeyed when such ranges are considered.  We are pioneering the development of experimental techniques and semi-empirical theoretical techniques for obtaining such data.  In addition to combustion, these studies are important to technological fields, such as manufacturing of petrochemicals, optical fibers, carbon black, as well as to metal refining, plasma processing, chemical vapor deposition and modeling of the atmosphere.

 

            The work includes design and construction of chemical reactors, experimentation, and development of reaction system models.  Reactive intermediates, produced by thermal, electrical discharge, and photolytic generation techniques, are used in conjuction with fast-flow and pseudo-static reactors.  These thermostatted reactors are constructed of ceramic and metal parts to allow operation in the 300 to 1800 K temperature regime.  Students involved with these projects gain experience with light sources, such as lasers, flash lamps, and electrical discharge lamps, combined with electro-optical detection techniques, to determine the time history of reactants.  Mass spectrometry is used for larger reactants and product identification.

 

            The theoretical work is based on quantum mechanics and uses standard computational chemistry packages.  The results are methods for engineering calculations of the temperature dependence of reaction rate coefficients from:  (i) reactions similar to those studied by the experimental methods mentioned above, or (ii) from a measurement on the reaction of interest at one temperature.

 

            Obtaining a better understanding of the temperature and pressure dependence of reaction rate coefficients is a major goal of this work.  Specific current topics include:  oxidation of toxic metals in waste incinerators; reactions of O, N, and NH radicals for the development of explosives; reactions of candidate replacements for halons as fire suppressants; the kinetics of ultraviolet chemiluminescence resulting from rocket-fuel combustion at high altitudes; the oxidation reactions of small ions.