The interrelations between the correlation coefficients (=r) for an Arrhenius representation (linearity lnk vs. 1/T) of runs evaluated by the one-step strategy, and their locations in the mechanistic diagram (reaction type indexM vs. shape indexS) are studied, based on 3000 DTA and UV experiments and 850 theoretical curves for 40 reaction mechanisms. It turns out that files corresponding to the source points of first- or second-order, or to theA-region located between, reveal a reliable Arrhenius line; but for particular mechanisms, files attributable to regions rather “distant” from this center, may also behave so. Therefore, further studies must lead to powerfulr,S,M-based kinetic pattern recognition methods.
Homogeneous solution reactions (half-life-time for 1 M solutionsτ20° > ≈ 10−4 sec, [ΔH] > 0.5 kcal/mole) have been investigated by non-isothermal differential calorimetry. By application of a new diagnostic procedure developed by use of an analogue computer, it can be decided whether the reactions of the substances tested are formal one-step processes, or what types of reaction-mechanisms must be considered. For the decompositions of some peroxide compounds the basic mechanism types, activation energies and action constants or entropies of the starting processes were determined. The cyclic furan ozonides have similar stabilities to that of the trioxide of di-isopropyl ether. On the other hand, triphenyl phosphite ozonide is considerably more unstable and can transfer oxygen to various acceptors below its decomposition temperature.