Method of iodide removal
The present invention provides a method of reducing the concentration of an iodide compound using an ion exchange resin. The ion exchange resin is a macroporous resin having sulfur functional groups exchanged with silver, a dry weight capacity of at least 5.0 eq/kg, a mean pore diameter (D 50 ) of about 400-800 Å, a pore volume of about 0.4-0.6 ml/g, and a surface area of about 20-40 m 2 /g.
1. A method of reducing the concentration of an iodide compound in a liquid comprising contacting the liquid with a resin, wherein the resin comprises a strong acid macroporous resin
having at least 1% of the acid functional groups exchanged with silver,
a dry weight capacity of at least 5.0 eq/kg,
a mean pore diameter (D 50 ) of about 400-800 Å,
a pore volume of about 0.4-0.6 ml/g, and
a surface area of about 20-40 m 2 /g.
2. The method of claim 1 , wherein the resin has a volume capacity of at least 1.40 eq/l.
3. The method of claim 1 , wherein the resin has a dry weight capacity is at least 5.1 eq/kg.
4. The method of claim 3 , wherein the resin has a dry weight capacity is at least 5.3 eq/kg.
5. The method of claim 1 , wherein the resin has a mean pore diameter (D 50 ) of at least 500 Å.
6. The method of claim 1 , wherein the resin has a mean pore diameter (D 50 ) of about 500-700 Å.
7. The method of claim 1 , wherein the silver loading is between 1 and 36% based on dry-weight resin base.
8. The method of claim 7 , wherein the silver loading is between 8 and 25% based on dry-weight resin base.
9. The method of claim 1 , wherein the resin polymer comprises approximately 70-92% polystyrene and approximately 8-30% divinylbenzene.
10. The method of claim 9 , wherein the resin polymer comprises approximately 75-85% polystyrene and approximately 15-25% divinylbenzene.
11. The method of claim 1 , wherein the iodide compound is one or more of a C 1 -C 12 alkyl.
12. The method of claim 1 , wherein the concentration of the iodide compounds is reduced to less than about 1 ppb.
13. The method of claim 12 , wherein the concentration of the iodide compounds is reduced to less than about 100 ppt.
14. The method of claim 1 , wherein contacting comprises flowing the liquid through a packed bed comprising the macroporous resin.
15. The method of claim 14 , wherein a flow rate is 5 to 15 bed volumes per hour.
16. The method of claim 1 , wherein the temperature of the resin is about 20° C. to about 40° C.
17. The method of claim 1 , wherein the solution is an acetic acid or acetic anhydride feedstock.
18. The method of claim 1 , wherein the liquid is an acetic acid solution, an acetic anhydride solution, or a peracetic acid solution.
19. The method of claim 1 , wherein the resin lifetime is at least one year.
20. The method of claim 1 , wherein the strong acid macroporous resin has at least 50% of the acid functional groups exchanged with silver,
a dry weight capacity of at least 5.2 eq/kg, and
a mean pore diameter (D 50 ) of about 500-800 Å.
wherein the temperature of the resin is about 20° C. to about 40° C.
21. A method of reducing the concentration of an iodide compound from an iodide-containing solution of acetic acid, acetic anhydride, or a mixture thereof comprising:
contacting the liquid with a packed bed comprising an ion exchange resin, wherein the resin comprises a strong acid macroporous resin
having at least 1% of the acid functional groups exchanged with silver,
a dry weight capacity of at least 5.0 eq/kg,
a mean pore diameter (D 50 ) of about 400-800 Å,
a pore volume of about 0.4-0.6 ml/g, and
a surface area of about 20-40 m 2 /g; and
maintaining the contact for a period of time sufficient to reduce the iodide concentration to less than 1 ppb.
22. The method of claim 21 , wherein contacting comprises flowing the solution through a packed bed comprising the macroporous resin.