Recovery process
AssigneeBP Chemicals Limited
InventorRichard B. A. Pardy
Life of this patent
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Abstract
A process for recovering a Group VIII noble metal catalyst, e.g. rhodium, from a liquid medium comprising Group VIII metal and a tar formed as a by-product in a carbonylation process is provided. The process comprises feeding the liquid medium to a first compartment of an electrodialysis cell and feeding a solvent to a second compartment adjacent the first. A voltage is applied to the electrodialysis cell to effect migration of the Group VIII metal from the first compartment to the second. The solvent used is preferably aqueous acetic acid.
Claims12
A process for recovering a Group VIII noble metal employed to catalyze a carbonylation reaction, said process comprising the steps of:
- providing a liquid medium comprising the Group VIII noble metal and tar, said tar having been formed as a by-product during the carbonylation reaction;
- feeding said liquid medium to a first compartment of an electrodialysis cell;
- feeding a solvent for at least said Group VIII noble metal to second compartments of said electrodialysis cell adjacent either side of said first compartment;
- applying a voltage across the electrodialysis cell to cause migration of the Group VIII noble metal in ionic form from said liquid medium into said solvent;
- and
- removing said solvent and the Group VIII noble metal in ionic form from said second compartments.
A process according to claim 10 wherein any promoters and copromoters employed in the carbonylation reaction are also recovered.
A process for recovering rhodium employed to catalyze a carbonylation of methyl acetate to produce acetic anhydride, said process comprising the steps of:
- providing a liquid medium comprising rhodium and tar, said tar having been formed as a by-product during the rhodium catalyzed carbonylation;
- feeding said liquid medium to a first compartment of an electrodialysis cell;
- feeding a solvent for at least the rhodium to second compartments of said electrodialysis cell adjacent either side of said first compartment;
- applying a voltage across said electrodialysis cell to cause migration of rhodium ions from said liquid medium into said solvent;
- and
- removing said solvent and the rhodium ions from said second compartments.
Dependencies are inferred from the claim text.