METHOD FOR OBTAINING PRECIOUS METALS FROM GROUP VIII OF THE PERIOD SYSTEM OF THE ELEMENTS TIED TO RESIDUES RESULTING FROM CARBONYLATION REACTIONS CATALYZED IN PRECIOUS METALS

摘要

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. The rhodium values are freed from the residues by treatment with amines, preferably primary aliphatic amines and/or hydrazine, thereby enabling the rhodium to be extracted by subsequent contact with an aqueous halogen acid.