Preparation of a highly fluorophilic phosphonium salt and its use in a fluorous anion-exchanger membrane with high selectivity for perfluorinated acids

Paul G. Boswell, Alyce C. Anfang, Philippe Bühlmann

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Fluorous solvents are the most nonpolar, nonpolarizable phases known, whereas ions are inherently polar. This makes it difficult to create salts that are soluble in a fluorous solvent. Here we present the synthesis and characterization of a new fluorophilic phosphonium salt, tris{3,5-bis[(perfluorooctyl)propyl]phenyl}methylphosphonium methyl sulfate. The salt has a solubility of at least 14 mM in perfluoro(perhydrophenanthrene), perfluoro(methylcyclohexane), and perfluorohexanes. It also shows immediate potential for use as a phase-transfer catalyst in fluorous biphasic catalysis, but in this work it is used as an anion-exchanger site in the first potentiometric fluorous-membrane anion-selective electrode. The membrane sensor exhibited the exceptional selectivity of 3.9 × 1010 to 1 for perfluorooctanesulfonate over chloride, and of 2.5 × 107 to 1 for perfluorooctanoate over chloride. With improvements to the sensor's detection limit and lifetime, it has the potential to be an attractive alternative to the expensive, time-consuming methods currently employed for measurement of perfluorinated acids.

Original languageEnglish (US)
Pages (from-to)961-967
Number of pages7
JournalJournal of Fluorine Chemistry
Volume129
Issue number10
DOIs
StatePublished - Oct 1 2008

Keywords

  • Fluorous
  • Ion-selective electrode
  • Perfluorinated acids
  • Phase-transfer catalyst
  • Phosphonium
  • Potentiometry

Fingerprint Dive into the research topics of 'Preparation of a highly fluorophilic phosphonium salt and its use in a fluorous anion-exchanger membrane with high selectivity for perfluorinated acids'. Together they form a unique fingerprint.

Cite this