Dependence of the extraction ability of organic compounds on their structure

Data on the dependence of the extraction ability of the principal classes of organic compounds on their structure are surveyed. Mono- and bi-dentate neutral organophosphorus compounds (NOPC), sulfoxides, amines, quaternary ammonium, arsonium, and phosphonium bases, amine and arsine oxides, organophosphorus acids and their salts, and crown-ethers are examined. It is shown that the extraction ability of the NOPC in relation to any metal increases with increase in the basicity of the extractant and diminishes when electronegative substituents are introduced into its molecule. With increase in the basicity of neutral extractants, qualitative changes in the complex formation mechanisms are observed. The influence of diluents on the extraction ability of organic compounds is analysed. Methods for predicting extraction ability are considered. Examples of the use of the above rules for the development of new extractants are presented. The bibliography includes 157 references.