Quasi-Invariants of Chemical Reactions with Nonideal Kinetics

Abstract

A method is developed to determine approximate dynamic kinetic invariants (quasi-invariants) of complex chemical reactions with nonideal general-form kinetic laws. The quasi-invariants are expressions relating nonequilibrium reactant concentrations and temperatures, measured in two or more experiments under different initial conditions (multiexperiments) that remain almost constant throughout the reaction. The number of quasi-invariants is determined by the number of independent reactants. The application of the method was illustrated by the example of a two-step reaction in an open system with the Marcelin- de Donder kinetics. The quasi-invariant curves obtained for this reaction were compared with the concentration curves for the entire reaction time. It was shown that the quasi-invariants vary over a narrower range than their corresponding concentrations and temperature in various temperatures; i.e., the quasi-invariants remain nearly constant over time. The method expands the range of tools for the solution of inverse problems of unsteady-state kinetics of chemical reactions in nonideal systems.