Characterizing the Effects of a "Switchable Water" Additive on the Aqueous Solubility of Small Molecules. Issue 16 (16th February 2018)

• Record Type: Journal Article
• Authors: Vanderveen, Jesse R.; Burra, Sarika; Geng, Jialing; Goyon, Alexandre; Jardine, Alexander; Shin, Hyejin E.; Andrea, Tamer; Dyson, Paul J.; Jessop, Philip G.
• Is Part Of: Chemphyschem. Volume 19:Issue 16(2018)
• Page Start: 2093
• Page End: 2100
• Publication Date: 2018-02-16
• Subjects: aqueous two-phase systems -- hydrotropy -- Kirkwood–Buff theory -- solutions -- switchable solvents; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.201701303
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: "Switchable water" is an aqueous solution containing a water‐soluble amine additive that exhibits CO2 ‐switchable properties, such as large changes in ionic strength, by forming an ammonium bicarbonate salt. Switchable water has been used to reversibly "salt‐out" organic compounds from water. This study explores the salting out of several compounds in switchable water when CO2 is present and also explores the solubility of small molecules in switchable water, compared to pure water, when CO2 is absent. The results show that organic compounds are generally more soluble in switchable water than pure water in the absence of CO2, but less soluble in the presence of 1 atm CO2 . Exceptions include carboxylic acids and phenols which, presumably due to their acidity, are more soluble in switchable water than in pure water, even when CO2 is applied. Kirkwood–Buff solvation theory was applied to gain insights into the effects of the amine additive on the aqueous solubility of caffeine. Furthermore, the switchable properties of the additives allow for the preparation of switchable aqueous two‐phase systems. Abstract : CO2 ‐switchable ionogens such as N, N, N′, N′‐tetramethylbutane‐diamine (TMBD) can act as switchable solubilizing/precipitating agents. When CO2 is absent, organic compounds are more soluble in aqueous solutions containing TMBD than in pure water. When CO2 is present, they are usually less soluble than in pure water. The same CO2 switching method can be used to create two different types of switchable aqueous two‐phase systems.