Noble Metals Dissolution Catalyzed by [AlCl₄^–]-Based Ionic Liquids

Abstract

Imidazolium-based ionic liquid mixtures with [NO 3 ] − and [AlCl 4 ] − anions were used as oxidizing agents for the dissolution of Au, Pd, and Pt metals under mild conditions. The thermodynamic reduction of [NO 3 ] − to [NO] is catalyzed by [AlCl 4 ] − anions and coupled with the oxidation process of noble metals. The developed ionic liquid system for dissolving Au can reactivate the Au 0 formed in the deactivation process of the catalyst in vinyl chloride production. This demonstrates the relevance of the herepresented work for technical noble metal recycling.