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A method of calculating the Arrhenius parameters has been proposed, based on an evaluation of the coordinates of intersection of greatly extended confidence regions determined in solving the inverse kinetic problem. The validity of this method is illustrated by comparison of the Arrhenius parameters found from non-isothermal and isothermal data reported by other investigators.The kinetic parameters characterizing the chemical stage of solid-phase reactions are determined by isothermal kinetic methods, provided certain approaches to the selection of a theoretical model are observed and rigid constraints are imposed on the experiment [1]. Such constraints may yield a positive result in non-isothermal kinetics [2] as well. However, finding t'he kinetic parameters from experimental data, i.e. solving an invers kinetic problem, may run into certain difficulties, for such problems are ill-posed mathematical problems characterized by a poor statement of the problem conditions (the determinant of the information matrix is close to zero). Therefore, such problems have no unique solution unless special methods are used [3]. This problem was analyzed in [4,5] for dynamic thermogravimetry conditions. The poor statement of the problem conditions determines its solution in the form of a greatly extended region, so that experimental data can be described with equal accuracy with the help of Arrhenius parameters A and E variable over a very wide range in this region, the compensative effect being an artefact of computation. Calculated by different methods, A and E characterize the mathematical method used rather than the reaction itself. This also follows from [6][7][8][9]. The artefact can be eliminated, The invariant characteristics of the process can also be calculated with a different, quite general means, by constructing a statistical model of the process as a polynomial [3]. In this paper a method is suggested for determining invariant values of the activation energy (E) and a pre-exponential factor (A), which corresponds to the above general approach. Isokinetic temperature and a polynomial as a polylinear expansion [12] are used in the method. This makes it very simple to use in computation and provides a very clear interpretation that reveals the physical meaning of the invariants

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