MULTI-EXPERIMENTAL INVARIANTS FOR CHEMICAL REACTIONS IN A GRADIENTLESS REACTOR

Abstract

New regularities of complex nonlinear chemical reactions proceeding through an arbitrary number of nonlinear stages in an open and closed isothermal gradientless reactor are described, regardless of the type of kinetic law (ideal law of acting masses, non-ideal kinetics of Marceline De Donde, etc.). For such reactions in an open reactor, the exact independent autonomous (not explicitly time-dependent) linear stoichiometric conservation laws are violated, but more general relations representing linear ordinary differential equations with respect to stoichiometric combinations of reagents are fulfilled. These equations have exact analytical solutions, which are non-autonomous nonlinear stoichiometric invariants based on a single mono-experiment with given initial conditions. The disadvantage of these ratios is their obvious dependence on time, which makes it difficult to verify them accurately in practice. The paper describes a non-standard method for obtaining autonomous invariants of an open gradient-free reactor, which are performed at any moment of the reaction transition process, are applicable to any nonlinear reactions with any kind of kinetic law of stages and are easily tested in practice. The method uses the ideas of dual- and multi-approaches that allow using the results of several non-stationary experiments conducted under any starting conditions. It is shown that using this method, it is possible to construct almost any number of partial nonlinear stoichiometric invariants for any given pairs of a series of multiexperiments. This allows them to be repeatedly rechecked and to increase the reliability of the identification of the reaction mechanism when solving the inverse problem in practice. The results obtained are illustrated by examples of specific reactions.