Dissociation extraction: Theoretical foundations and applications

Dissociation extraction (DE) is a separation method that has been known for many decades but is not yet widely used in industry. However, there are a number of applications for which DE may be applied, for example, for new biorefinery separations. To facilitate future applications, we derived a new shortcut method for DE processes and demonstrated its application in the conceptual design of a separation process for acidic and basic organic mixtures. The new method allows for the calculation of the minimum energy requirement and a fast comparison of dissociation extraction with other separation methods. The shortcut method was validated using experimental data from the literature and is easy to implement because it is based only on the physical distribution coefficients and dissociation constants of the acids or bases to be separated. In the second part of this paper, we identify several areas that require effective separation techniques, where dissociation extraction can have an impact. These include biorefinery separation, polymer recycling, and fatty acid fractionation. In conclusion, we hope to promote DE as a known but less-used separation method for difficult separation problems in both fossil-based and bio-based sustainable chemical products.