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Significant Acceleration of PGMs Extraction with UCST-Type Thermomorphic Ionic Liquid at Elevated Temperature
- Kono, Soma, Kazama, Hiroyuki, Mori, Takahiro, Arai, Tsuyoshi, Takao, Koichiro
- ACS sustainable chemistry & engineering 2018 v.6 no.2 pp. 1555-1559
- ionic liquids, nitric acid, platinum, rhodium, ruthenium, temperature
- 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.