Correlate the nature of diluent:

Several efforts have been made to correlate the nature of diluent with extraction power of an amine. As a matter of fact, the lack of correlation between the distribution ratio of metal and physical characteristics of a solvent such as dipole moment and dielectric constant has led to the conclusion that the amine-diluent combination rather than amine alone should be considered as the effective extractant. There are some limitations in using these reagents as extractants. The most usually encountered is the formation of emulsion. This problem can be effectively tackled by choosing a low surface active extractant and a proper diluent. Control of conditions like temperature, pretreating acid, amount of free acid in aqueous phase and the volume of the two competing phases help to minimize this problem. In some cases, spectacular reduction in emulsion formation has been observed by the addition of 2-3 % higher alcohols.