Design of green microorganized systems for decontamination of ecotoxicants

Abstract

Due to population upsurge, pesticides (derivatives of organophosphorus acids included) find widespread use in agriculture. The toxicity and long-term environmental hazard of such compounds require detailed studies on decomposition mechanisms of the pesticides and development of efficient, readily available, and inexpensive systems for their decontamination. A simple and straightforward method for the decomposition of organophosphorus compounds involves their reactions with nucleophiles. Studies on the reactivity of "normal" and α-nucleophiles toward electron-deficient centers allowed us to state a number of basic principles on the nature of the α-effect. One of the most important conclusions is: It is unlikely that the structure variations in the known α-nucleophiles will result in higher reactivity than that of hydroxylamine anion. As a practical matter, the essential disadvantages of decomposition of organophosphorus compounds in water and organic solvents are: (i) instability of active nucleophiles and oxidizing agents, (ii) corrosiveness, and (iii) extremely low solubility of organophosphorus compounds in water. These dictate the strategy of further studies, namely, carrying out the reaction in microorganized media. The first research line involves the development of the functional imidazole-based detergents functionalized with α-nucleophilic fragments. A number of efficient detergents were first synthesized. An examination of the nucleophilicity of the functional fragments in water and in the micellar phase and quantitative assessment of the factors responsible for the micellar effects showed unambiguously that the main cause of the observed accelerations is the substrate concentrating in the micellar pseudophase. The second research line consists of studies on the reactivity of versatile oxidative/nucleophilic systems involving H2O2/activator and polyhalide ion organocomplexes in water, aqueous alcohols, and micelles of cationic detergents. The novel sources of "active" halogen are highly competitive both with conventional hazardous chlorine derivatives and "green" systems involving H2O2/activator.