Solvent extraction and extraction?voltammetric determination of phenols using room temperature ionic liquid

Abstract

The phenolic compounds phenol, 4-nitrophenol, 2,4-dinitrophenol, 2,6-dinitrophenol, 1-naphthol, 2-naphthol, and 4-chlorophenol are extracted nearly quantitatively from aqueous solution into the room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMImPF6) in molecular form at pH < p Ka. Picric acid is extracted efficiently in anionic form. Recovery of pyrocatechol and resorcinol is much lower. The effect of pH, phenol concentration, and volume ratio of aqueous and organic phases were studied. Ionic liquid BMImPF6 is shown to be suitable for extraction-voltammetric determination of phenols without back-extraction or addition of support electrolyte. The electrochemical window of BMImPF6 at various electrodes was determined, and voltammetric oxidation of phenols and reduction of nitrophenols in BMImPF6 was studied.

Ionic Liquids in Separation Techniques

“…This result is in consistent with the solvation model proposed by Abraham et al (Abraham et al, 2003) indicating that BMIM PF 6 has a greater affinity for electron lone pair interactions. More data for liquid-ionic liquid partition coefficients of different organic compounds were described for the biphasic systems containing alkyl ammonioum ionic liquids: ethylammonium nitrate, n-propylammonium nitrate, or di-n -propylammonium thiocyanate and hexane, toluene, octan-1-ol, or dichloromethane (Poole, 2007;Shetty et al, 1987;Shetty et al, 1990) or aqua biphasic systems formed by 1-butylammonium-3-methylimidazolium hexafluorophosphate and water or heptane ( Berthod & Carda-Broch, 2003;Khachatryn et al, 2005;Carda-Broch et al, 2003) or the 1-octyl-3-methylimidazolium hexafluorophosphate-water biphasic system . IL additives have been also applied as a mobile phase modifiers in RP-HPLC systems used for determination of the chromatographic lipophilicity parameters log k w of ionized forms of basic drugs (Marszałł & Kaliszan, 2007).…”

Mutual Solubility of Hydrophobic Ionic Liquids and Water in Liquid-Liquid Two-phase Systems for Analytical Chemistry

“…[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Among many possibilities of applying ionic liquids, IL-water (W) two-phase systems that consist of an aqueous or a nonpolar molecular solvent and an ionic liquid are of considerable relevance with analytical chemistry and separation technology. A direct application of IL-W two-phase systems is the extraction of neutral compounds of relatively low molecular weights, [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] biopolymers 44,[48][49][50][51] and ions. Several reviews on extraction with ILs are available.…”

Research trends in electrochemical technology for water and wastewater treatment

“…In addition, ''ionic liquid(s)'' and ''carbon nanotube(s)'' might be new hot topics in the future since both of them did not appear in 1994-1998, but ranked 6th and 8th in 2009-2013, respectively. Ionic liquid(s), which could supply a suitable and stable environment, which draw a great attention on electrode modification (Wadhawan et al 2000;Rozniecka et al 2005), electrolyte solutions (Markevich et al 2006;de Souza et al 2007), and extraction of solvent and metal ions (Wei et al 2003;Khachatryan et al 2005). In previous researches (Munoz-Sandoval 2014), carbon nanotube(s) related literatures had increased enormously and represented a very important material in nanotechnology and nanoscience area.…”