Prediction of molecular recognition-enhanced phenobarbital extraction based on solvatochromic analysis

The extraction efficiency for organic molecules using synthetic receptors is highly dependent on solvent properties. Solvent influences the partitioning of both the desired compound and the interfering species. Solvent also influences the solubility of the receptor and its affinity for the substrate. Therefore the free energy involved in extraction can be optimized by using a carefully selected solvent. In this paper we demonstrate the use of a solvatochromic model to predict the influence of solvent dipolarity, H-bond acidity and H-bond basicity on selectivity and yield of phenobarbital extraction. We also used this method to estimate the purity and yield of phenobarbital extraction in 12 poly(vinyl chloride) plasticizers and solvents. This approach can be generalized for assisting the selection of optimal solvent and provide insight into the rational design of solvent and receptor for industrial extractions.