Получение и применение комплексов лигносульфоновых кислот с катионами железа

Abstract

Lignosulfonates and lignosulfonic acids are the main commercial product on the world market of lignins. They are used in metallurgy, mining, concrete production, and agriculture. The review presents the results of studying the structure and properties of lignosulfonates, the synthesis and application of complexes of lignosulfonic acids with iron cations. Lignosulfonates possess unique physicochemical properties that other types of lignins do not have. They form chelate complexes when interacting with iron cations and other biogenic metals. These complexes can be used in agriculture to eliminate plant chlorosis. Chlorosis is particularly manifests itself on about 30 % of the world's farmlands with high calcium carbonate content. It is possible to change the properties of lignosulfonic acids and lignosulfonates intentionally by theirmodification. Nitration and nitrosation enhances the complexing properties. This is due to the possibility of the formation of chelate complexes with iron cations. Iron chelates with nitrated and nitrosated lignosulfonates exhibit strong antichlorosis properties. Their use allows normalizing the content of chlorophyll in photosynthetic structures completely. In the synthesis of water-based magnetic fluids lignosulfonates modified by nitration and nitrosation exhibit the properties of a peptizing agent that promotes the formation of stable magnetic fluids of magnetite type. Lignosulfonates have a strong influence on the synthesis of magnetoactive compounds by the partial oxidation of iron (II) cations using chromate ions or silver ammonium hydroxide. In the former case, a compact magnetoactive compound is formed; and in the second - a magnetic fluid (if condensation is carried out in the presence of tetraalkylammonium hydroxides).