PROCEDIMENTO PER IL RICUPERO DI UN CATALIZZATORE DI RODIO

摘要

A process for recovering rhodium catalyst from a liquid composition comprising rhodium catalyst and tar by liquid-liquid extraction. The liquid composition is formed during the preparation of acetic anhydride in a carbonylation process by reacting carbon monoxide gas with methyl acetate in the presence of a catalytic combination of rhodium, lithium and an iodine compound The rhodium catalyst is recovered in aqueous phase by contacting the liquid composition with two extracting liquids, aqueous hydrogen iodide and methyl acetate. The presence of hydrogen iodide in the aqueous phase stabilizes the rhodium catalyst in a water-soluble form and prevents rhodium losses due to plating out of rhodium on process equipment.