The paper discusses the decomposition mechanisms of hydrogen peroxide (HP) under the action of light, with the involvement of metal ions and their coordination compounds, as well as the participation of hydrogen peroxide in the peroxidase oxidation of various chemical substances. It is shown that these reactions are accompanied by the formation of partial charge transfer complexes and other short-living species as intermediates. Water self-purification capacity following the chemical way is discussed. New indicators for estimating the quality of natural water bodies have been proposed. HP plays an essential role in strengthening the immune system of living organisms, serving in the fight against various diseases, including COVID-19. In this regard, a kinetic model is proposed to evaluate and predict viral infections. We have experimentally demonstrated that HP can find broad applications in agriculture, specifically, in seed treatment, plant growth acceleration, the food industry, etc.
TopIntroduction
Approximately 2.5 billion years ago, the Earth's atmosphere did not contain free molecular oxygen at all and was purely reductive in nature. But, as proved quite recently, even in the absence of oxygen, which is usually a precursor of hydrogen peroxide, the latter could be formed as a result of tectonic processes of crustal rock fracture during the mechanochemical reactions (Stone et al., 2022). Hydrogen peroxide can be found everywhere, even in outer space in the interstellar medium (Bergman et al., 2011). And it is formed everywhere in the natural aquatic environment (oceans, seas, rivers, lakes, and even swamps) under solar irradiation (Cooper et al., 1988).
It was shown experimentally that hydrogen peroxide in the environment is the main oxidizing agent in the processes of chemical self-purification of environmental compartments and the formation of chemical composition appropriate to the biological value of habitation (Duca et al., 1995). Over the past 200 years, oxidative reactions involving H2O2 and their mechanisms have been studied using both laboratory and natural systems. Beginning from hydrogen peroxide discovery in 1818 by Jacques Louis Thenard, based on the reaction:
BaO
2 + 2HNO
3 = Ba(NO
3)
2 + H
2O
2(1)Hydrogen peroxide still demonstrates unexpected properties which require additional studies and explanations (Cotton et al., 1994). In this chapter, we attempt to reveal the role of hydrogen peroxide in science, nature, health (biopharmaceuticals), and technology. Comprehensive studies of the important chemical and biological systems involving hydrogen peroxide have been started in “N.N. Semenov” Institute of Chemical Physics, Russian Academy, and Moldova State University.
The history of hydrogen peroxide research as a model for studying redox mechanisms began in the 1950s with the works of Prof. Anatol Purmal, Yurii Skurlatov, Yurii Kozlov, Sergey Travin from the Institute of Chemical Physics of the Russian Academy and Prof. Alexei Sychev, Victor Isac, Jacob Tighineanu, Gheorghe Duca, Maria Gonta, Victor Covaliov, Viorica Gladchi, Lidia Romanciuc from the Moldova State University. These studies are currently being continued in the Institute of Chemistry, research laboratory of Kinetics, Quantum Chemistry, and Physical Research Methods (Duca, 2017, 2007; Duca et al., 2002).