Significant Acceleration of PGMs Extraction with UCST-Type Thermomorphic Ionic Liquid at Elevated Temperature

Soma Kono, Hiroyuki Kazama, Takahiro Mori, Tsuyoshi Arai, Koichiro Takao

Research output: Contribution to journalArticle

5 Citations (Scopus)


Dependency of extraction behavior of inert platinum group metals (PGMs) like Ru(III) and Rh(III) on temperature has been investigated in a biphasic system consisting of HNO3(aq) and betainium bis(trifluoromethylsulfonyl)amide ([Hbet][Tf2N]) ionic liquid. The extraction reactions of Ru(III) and Rh(III) took 3.5 days and 113 days, respectively, at 298 K, while equilibrated within 1 and 3 h to reach 99.2% and 96.5% extraction at 353 K. Further mechanistic studies clarified that the complexation of these PGMs and [Hbet]+ is rate-determining in their extraction and that it is successfully accelerated and enhanced by elevating the temperature.

Original languageEnglish
Pages (from-to)1555-1559
Number of pages5
JournalACS Sustainable Chemistry and Engineering
Issue number2
Publication statusPublished - 2018 Feb 5



  • Betainium
  • Ionic liquid
  • Platinum group
  • Solvent extraction
  • Thermomorphism
  • Upper critical solution temperature

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment

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