Synergistic Chloroform-Methanol Binary Solvent Mixture Is Inherently Spatially and Dynamically Heterogeneous.

Abstract

Nonideality in a binary solvent mixture is manifested through anomalies in various physical properties like viscosity, dielectric constant, polarity, freezing point, boiling point, and so forth. Sometimes, such anomalies become much more prominent, leading to a synergistic behavior, where the physical property of the mixture is way different from its bulk counterparts. Various alcohols/chlorinated methane binary solvent mixtures show such a synergistic behavior. The reason is attributed to the unique but diverse interactions present in the system. We speculated that these diverse interactions must manifest heterogeneity in such a binary solvent mixture. Using the improved methodology developed by our group, we investigate the presence of dynamic and spatial heterogeneity in the chloroform/methanol synergistic binary solvent mixture. To our delight, we found that our projection is accurate, and indeed, the chloroform/methanol binary solvent mixtures are heterogeneous. Two maxima for the synergistic behavior have been observed for the chloroform/methanol binary solvent mixture (at ∼0.45 and 0.75 mole fractions of methanol in chloroform) in the literature, where the extent of heterogeneity was also found to be the highest. The present study portrays the intriguing complexity of simple binary solvent mixtures, and the findings may provide valuable insights into solvent engineering for diverse applications like extraction/purification media, reaction media, polymer processing, nanomaterial synthesis, pollutant extraction, active ingredient delivery, biofuel production, and battery technology.