| abstract |
Residues are formed in the carbonylation of esters or ethers, particularly in the production of acetic anhydride or ethylidene diacetate. Such residues contain noble metal, typically rhodium used as a catalyst, which must be recovered before the residues can be disposed of. In the process of the invention, the rhodium values are freed from the residues by a series of treatments with amines and other reagents, thereby enabling the rhodium to be extracted by subsequent contact with an aqueous halogen acid. |