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

Imidazolium-based ionic liquid mixtures with [NO3]− and [AlCl4]− anions were used as oxidizing agents for the dissolution of Au, Pd, and Pt metals under mild conditions. The thermodynamic reduction of [NO3]− to [NO] is catalyzed by [AlCl4]− anions and coupled with the oxidation process of noble metals. The developed ionic liquid system for dissolving Au can reactivate the Au0 formed in the deactivation process of the catalyst in vinyl chloride production. This demonstrates the relevance of the here-presented work for technical noble metal recycling.