Introduction

The phenomenon of the heterogeneous–homogeneous and homogeneous–heterogeneous reactions of oxidation, often named bimodal oxidation sequences or bimodal oxidation, is the main subject of this work. Previously, bimodal reaction sequences were revealed in the chain-radical and, in part, in heterogeneous catalytic reactions. For a long time, it was considered that this phenomenon was not widespread in chemistry. Only in recent decades did it become evident that these reactions are much more abundant not only in human-made but also in natural chemical systems.