As already mentioned, the framework of conceptual DFT relies on certain assumptions such as early transition states and weak deformations in terms of constant nuclear potentials. Accordingly, it can be concluded that only general trends fpr unimolecular reactions can be elucidated with the proposed approach. One can expect that higher order reactions which include a significant rearrangement of covalent bonds show certain deviations. The first two considered reactions in Fig. include the catalytic isomerization of methyl eugenol to trans-methyl isoeugenol (reaction 1) and cis-methyl isoeugenol (reaction 2). The corresponding yields were reported in Ref. 57. Different catalysts including FeCl 2 ,