Iodine-catalysed dissolution of elemental gold in ethanol

Zupanc, Anže (author), Heliövaara, Eeva (author), Moslova, Karina (author), Eronen, Aleksi (author), Kemell, Marianna (author), Podlipnik, Črtomir (author), Jereb, Marjan (author), Repo, Timo (author)

Gold is a scarce element in the Earth’s crust but indispensable in modern electronic devices. New, sustainable methods of gold recycling are essential to meet the growing eco-social demand of gold. Here, we describe a simple, inexpensive, and environmentally benign dissolution of gold under mild conditions. Gold dissolves quantitatively in ethanol using 2-mercaptobenzimidazole as a ligand in the presence of a catalytic amount of iodine. Mechanistically, the dissolution of gold begins when I$_2$ oxidizes Au$^0$ and forms a [Au$^I$I$_2$]$^−$ species, which undergoes subsequent ligand-exchange reactions and forms a stable bis-ligand Au$^I$ complex. H$_2$O$_2$ oxidizes free iodide and regenerated I$_2$ returns back to the catalytic cycle. Addition of a reductant to the reaction mixture precipitates gold quantitatively and partially regenerates the ligand. We anticipate our work will open a new pathway to more sustainable metal recycling with the utilization of just catalytic amounts of reagents and green solvents.

• Language: English
• Keywords: gold, iodine, sustainable chemistry, catalysis, recycling
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Version of Record
• Year: 2022
• Number of pages: 6 str.
• Numbering: Vol. 61, iss. 14, art. e202117587
• PID: 20.500.12556/RUL-145560
• UDC: 546.15-44
• ISSN on article: 1433-7851
• DOI: 10.1002/anie.202117587
• COBISS.SI-ID: 119460867
• Publication date in RUL: 21.04.2023

Record is a part of a journal

• Title: Angewandte Chemie : international edition
• Shortened title: Angew. Chem.
• Publisher: Wiley, GDCh
• ISSN: 1433-7851
• COBISS.SI-ID: 18592005

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: zlato, jod, trajnostna kemija, kataliza, recikliranje