Synthesis of Environmentally Safe Antiwear Additives to Lubricating Materials: State of the Art and Prospects

The review deals with the development and production of synthetic additives to lubricating oils and plastic lubricants, influencing the friction and wear of metal surfaces. The state of the art of the synthesis and use of such additives based on organic, organoelement, and metal-containing compounds is considered. New synthetic routes to relatively safe and low-toxic compounds with minimal content of environmentally harmful elements (chlorine, phosphorus, sulfur, metals) are described, and their use as antiwear additives to lubricating materials is analyzed. Despite large number of the suggested new antiwear additives, it is difficult to expect that an optimum combination of tribological properties will be reached in a molecule of a single additive as in the case of additives based on zinc dialkyl dithiophosphates.