Considerations in the Study of Reaction Sets

Abstract

Abstract Absolute rate constants are shown to be inherently inaccurate, whereas relative rate constants are practically independent of operating conditions and the errors in their measurements. Consequently selectivity analyses should be made by using reaction paths in composition space. Single reactions are regarded as approximations of sets within a constrained range of conditions. When the range is varied widely, other reactions of the set become predominant. Extremely fast sets of reactions also behave as single reactions. There is a limit to the complexity of a reaction network that can provide useful information in an overall rather than a nodal analysis. Grouping of species then becomes an important data-analysis technique, and catalyst behavior can be described by using semiempirical unimolecular power-law or completely empirical hyperbolic reaction paths. The former procedure develops a measure of fundamental comprehesion, even with mixtures of partially or completely unknown stoichiometry. Neith...