Catalyst recovery process from tar from carbonylation reactions

• US 4,434,241 A
• Filed: 09/27/1982
• Issued: 02/28/1984
• Est. Priority Date: 09/27/1982
• Status: Expired due to Term

• Current Assignee: Eastman Chemical Company
• Original Assignee: Eastman Kodak Company
• Inventors: Larkins, Thomas H. Jr.
• Primary Examiner(s): Konopka, P. E.
• Application Number:
  US06/424,727
• Time in Patent Office: 519 Days
• Field of Search: 252/413, 252/412, 252/420, 252/416, 423/22, 423/179.5, 423/488, 423/504, 260/549
• US Class Current: 502/24
• CPC Class Codes: B01J 2231/34 Other additions, e.g. Monsanto-type carbonylations, addition to 1,2-C=X or 1,2-C-X triplebonds, additions to 1,4-C=C-C=X or 1,4-C=-C-X triple bonds with X, e.g. O, S, NH/N
• CPC Class Codes: B01J 23/464 Rhodium
• CPC Class Codes: B01J 2531/822 Rhodium
• CPC Class Codes: B01J 31/20 Carbonyls
• CPC Class Codes: B01J 31/26 containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24
• CPC Class Codes: B01J 31/4046 containing rhodium
• CPC Class Codes: B01J 31/4092 involving a stripping step, with stripping gas or solvent
• CPC Class Codes: C01B 7/13 Iodine; Hydrogen iodide
• CPC Class Codes: C07C 51/573 Separation; Purification; Stabilisation; Use of additives
• CPC Class Codes: C07C 53/12 Acetic anhydride ketene C07C49/90
• CPC Class Codes: C22B 11/04 by wet processes extraction of metal compounds by leaching in organic solutions C22B3/16; treatment or purification of solutions by liquid-liquid extraction C22B3/26
• CPC Class Codes: C22B 26/12 Obtaining lithium
• CPC Class Codes: C22B 3/165 with organic acids
• CPC Class Codes: C22B 7/007 by acid leaching
• CPC Class Codes: Y02P 10/20 Recycling
• CPC Class Codes: Y02P 20/584 Recycling of catalysts

Abstract

The present invention provides a process for the recovery of rhodium, lithium, and iodine values from tar which is generated during carbonylation reactions. The process comprises sequentially extracting the tar with water and then leaching the remaining tar with acetic acid, burning the resulting residue, and recycling the resulting rhodium-enriched residue to the reaction process. Preferably, the process further comprises the recovery of iodine values by the incineration of the acetic acid leachate and treatment of the off-gas with aqueous alkali hydroxide. Lithium values are recovered by evaporating water from the aqueous phase of the water extraction step and recycling the resulting residue to the reaction process.

Claims

1. A process for the recovery of rhodium, lithium, and iodine values from tar which is generated during carbonylation reactions comprising the steps of:

(a) vaporizing volatile components from said tar;

(b) adding water to the remaining tar and heating the resulting mixture so as to extract corrosion metal ions and lithium ions into the aqueous phase;

(c) separating said aqueous phase;

(d) drying the resulting tar residue and leaching said residue with acetic acid at reflux temperature so as to remove iodine species, soluble organic polymers, and corrosion metal ions from said residue;

(e) burning said residue at a temperature and for a period of time sufficient to remove carbonaceous impurities therefrom; and

(f) recycling the rhodium-enriched residue to the reaction process.

2. The process of claim 1 which comprises the additional steps of concentrating the acetic acid leachate and burning the resulting concentrate;

scrubbing the off-gas from said burning step with aqueous alkali hydroxide;

adding sulfuric acid to the resulting iodide-containing alkali hydroxide solution; and

heating the resulting sulfuric acid solution so as to distill and recover HI/I₂.

3. The process of claim 1 which comprises the additional steps of evaporating water from the aqueous phase of the water extraction step and recycling the resulting residue to the reaction process.

4. A process for the recovery of rhodium, lithium, and iodine values from tar which is generated durin the carbonylation of methyl acetate to acetic anhydride comprising the steps of:

(a) vaporizing volatile components from said tar;

(b) adding water to the remaining tar and heating the resulting mixture so as to extract corrosion metal ions and lithium ions into the aqueous phase;

(c) separating said aqueous phase;

(d) evaporating water from said aqueous phase and recycling the resulting lithium-rich residue to the reaction process;

(e) drying the tar residue from the water extraction step and leaching said residue with acetic acid at reflux temperature so as to remove iodine species, soluble organic polymers, and corrosion metal ions from said residue;

(f) burning said residue at a temperature and for a period of time sufficient to remove carbonaceous impurities therefrom;

(g) recycling the rhodium-enriched residue to the reaction process;

(h) concentrating the acetic acid leachate and burning the resulting concentrate;

(i) scrubbing the off-gas from said burning step with aqueous alkali hydroxide;

(j) adding sulfuric acid to the resulting iodide-containing alkali hydroxide solution; and

(k) heating the resulting sulfuric acid solution so as to distill and recover HI/I₂.