Simple amides and amines for the synergistic recovery of rhodium from hydrochloric acid by solvent extraction
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Published version
Author(s)
Type
Journal Article
Abstract
The separation and isolation of many of the platinum group metals (PGMs) is currently achieved commercially using solvent extraction processes. The extraction of rhodium is problematic however, as a variety of complexes of the form [RhCln(H2O)6-n](n−3)− are found in hydrochloric acid, making it difficult to design a reagent that can extract all the rhodium. In this work, the synergistic combination of a primary amine (2-ethylhexylamine, LA) with a primary amide (3,5,5-trimethylhexanamide, L1) is shown to extract over 85 % of rhodium from 4 M hydrochloric acid. Two rhodium complexes are shown to reside in the organic phase, the ion-pair [HLA]3[RhCl6] and the amide complex [HLA]2[RhCl5(L1)]; in the latter complex, the amide is tautomerized to its enol form and coordinated to the rhodium centre through the nitrogen atom. This insight highlights the need for ligands that target specific metal complexes in the aqueous phase and provides an efficient synergistic solution for the solvent extraction of rhodium.
Date Issued
2021-04-08
Date Acceptance
2021-04-01
Citation
Chemistry – A European Journal, 2021, 27 (34), pp.8714-8722
ISSN
0947-6539
Publisher
Wiley
Start Page
8714
End Page
8722
Journal / Book Title
Chemistry – A European Journal
Volume
27
Issue
34
Copyright Statement
© 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
License URL
Identifier
https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202100630
Subjects
Science & Technology
Physical Sciences
Chemistry, Multidisciplinary
Chemistry
critical metals
hydrometallurgy
recycling
sustainability
synergistic
PLATINUM-GROUP METALS
SELECTIVE RECOVERY
SEPARATION
RH(III)
CHLORIDE
SPECIATION
COMPLEXES
PT(IV)
MEDIA
GOLD
critical metals
hydrometallurgy
recycling
sustainability
synergistic
Amides
Amines
Hydrochloric Acid
Rhodium
Solvents
Hydrochloric Acid
Rhodium
Amides
Amines
Solvents
General Chemistry
03 Chemical Sciences
Publication Status
Published
Article Number
chem.202100630
Date Publish Online
2021-04-08