CN-122029126-A - Method for obtaining iodide ions from a solution comprising an iodine-containing aromatic compound

Abstract

The present invention relates to a method for obtaining iodide ions from a solution containing a small amount of an iodinated aromatic compound (e.g., a nonionic X-ray contrast agent), the method comprising the steps of contacting the solution containing a small amount of an iodinated aromatic compound with activated carbon, thereby adsorbing the iodinated aromatic compound contained therein onto the activated carbon, and deiodinating the iodinated aromatic compound adsorbed onto the activated carbon.

Inventors

• BUONSANTI FEDERICA
• G. L. Sialcero
• R. Freta
• A. P. Debyshev
• T. Zaninelli

Assignees

• 伯拉考成像股份公司

Dates

Publication Date

20260512

Application Date

20241126

Priority Date

20231128

Claims (20)

1. 1. A process for obtaining iodide ions (I - ) from an aqueous solution comprising at least one iodinated aromatic compound in an amount of 2% w/w or less in the aqueous solution, the process comprising the steps of: a) Contacting the aqueous solution with activated carbon to adsorb the iodine-containing aromatic compound contained therein onto the activated carbon, and B) Deiodination of the iodine-containing aromatic compound adsorbed onto the activated carbon, thereby obtaining iodide ions.
2. 2. The method of claim 1, wherein the amount of iodine-containing aromatic compound is 1.0% or less.
3. 3. The method of claim 2, wherein the amount of iodine-containing aromatic compound is 0.5% w/w or less.
4. 4. A process according to claim 3, wherein the amount of iodine containing aromatic compound is 0.05% w/w or less.
5. 5. The method of claim 4, wherein the amount of iodine containing aromatic compound is 0.02% w/w or less.
6. 6. The method of claim 5, wherein the amount of iodine containing aromatic compound is 0.01% w/w or less.
7. 7. The method of any one of claims 1 to 6, wherein the iodine-containing aromatic compound is a non-ionic X-ray contrast agent.
8. 8. The method of claim 7, wherein the non-ionic X-ray contrast agent is selected from iodixanol, iohexol, iomeprol, iopamidol, iopentol, iopromide, ioversol, ioxilan, ioxacoo, ioxamide, iobixel, and iodic acid.
9. 9. The method of claim 8, wherein the non-ionic X-ray contrast agent is selected from the group consisting of iopamidol, iomeprol, iohexol, ioxilan, iopromide, iobiol, iodixanol, iobiol, and ioversol, more preferably from the group consisting of iomeprol and iopamidol.
10. 10. The method of claim 9, wherein the non-ionic X-ray contrast agent is iopamidol.
11. 11. The method according to any one of claims 1 to 10, wherein step a) is performed by flowing the aqueous solution through activated carbon.
12. 12. The method of claim 11, wherein the activated carbon is disposed in one or more columns.
13. 13. The method of claim 12, wherein the activated carbon is disposed in more than one column.
14. 14. The method of any one of claims 1 to 13, wherein the activated carbon is granular activated carbon.
15. 15. The method of claim 14, wherein 10 wt% or less of the granular activated carbon has a particle size of less than 0.425 mm (40 mesh) and 15wt% or less of the granular activated carbon has a particle size of greater than 1.70 mm (12 mesh).
16. 16. The method of claim 15, wherein 5 wt% or less, preferably 4 wt% or less of the particle size is below 0.425 mm (40 mesh) and 10 wt% or less, preferably 5 wt% or less of the particle size is above 1.70 mm (12 mesh).
17. 17. The method according to any one of claims 1 to 16, wherein the activated carbon is made from at least 50% coal, preferably from at least 70% coal, more preferably from at least 80% coal, and even more preferably from 90% coal.
18. 18. The process according to any one of claims 1 to 17, wherein after the deiodination step b), the activated carbon is reused in step a).
19. 19. The method according to any one of claims 1 to 18, wherein step b) is performed by contacting the iodine-containing aromatic compound adsorbed onto the activated carbon with copper ions and OH - ions.
20. 20. The method of claim 19, wherein the amount of OH - ions is 0.5 moles per mole of adsorbed organic iodine or more.

Description

Method for obtaining iodide ions from a solution comprising an iodine-containing aromatic compound Technical Field The present invention relates to a process for recovering iodide ions from a solution containing a small amount of an iodine-containing aromatic compound. Background Iodine-containing aromatic compounds find a variety of uses in different technical fields, for example in the diagnostic field. In fact, the radiographic contrast agents commonly used in clinical applications (i.e., non-ionic X-ray contrast agents) are iodine-containing aromatic compounds. In fact, the structure of commonly used non-ionic X-ray contrast agents is characterized by one or more tri-iodinated aromatic rings in which iodine is covalently bound to carbon atoms of one or more aromatic rings. Examples of non-ionic X-ray contrast agents are iodixanol, iohexol, iopentol (iopentol), iopromide, ioversol, ioxilan (ioxilan), ioxacoo (iosarcol), iogulamide (iogulamide), iodic acid (iodamide), iomeprol, iobitterol and iopamidol. Iodine recovery is a critical part of the production of iodine-containing aromatic compounds for both economic and environmental reasons. In fact, iodine is an expensive and rare starting material and its emissions are very severely limited. Conventionally, iodine is recovered by deiodinating an iodine-containing aromatic compound such that covalent bonds between iodine and carbon are broken, thereby obtaining iodide ions (typically dissolved in an aqueous solution). The iodide ions may then be converted to any particular form such as is conventionally used for iodination and/or to molecular iodine (I 2) according to known methods. Thus, obtaining iodide ions is a key point for iodine recovery. During the preparation of the iodine-containing aromatic compounds, residual amounts of iodine-containing aromatic compounds may be lost due to plant losses, leaks, industrial washing and other similar operations. Even recovery of iodine from these residual amounts is important for the economic and environmental reasons described above. However, recovery of iodine in satisfactory yields from wastewater containing residual amounts of iodinated aromatic compounds, especially from tri-iodo aromatic compounds having highly substituted side groups, e.g. from non-ionic X-ray contrast agents for clinical use, can be difficult. WO 2018/224581 discloses a process for recovering and recycling iodine from an aqueous solution comprising an iodine-containing aromatic compound having a pH below 1 in the absence of a catalyst. This document also discloses a step for recovering optional residual traces of organic iodine, which step comprises (i) feeding the aqueous solution from the upstream step into a column filled with char, whereby the organic iodine is immobilized on the char, and then (ii) desorbing the immobilized organic iodine using a suitable solvent or base (e.g. 30% naoh in the absence of a catalyst), thereby providing a concentrated solution of organic iodine, which can be processed conventionally to obtain iodide ions. WO 2018/224581 illustrates the treatment of mono-, di-and tri-iodinated derivatives of 5-amino-1, 3-phthalic acid according to this absorption-desorption procedure: triiodinated derivatives of 5-amino-1, 3-phthalic acid These derivatives are common intermediates for iodine-containing aromatic compounds (e.g. iopamidol) conventionally used in clinical applications for X-ray imaging, and have simpler and lighter pendant groups bonded compared to the latter. In view of the above, there is a need to provide methods for treating wastewater containing small amounts of iodine-containing aromatic compounds in satisfactory yields, which methods are not necessarily limited to the usual intermediates for treating non-ionic X-ray contrast agents, that is to say, methods for also treating iodine-containing aromatic compounds bonded to more complex and heavier side groups than those mentioned in the prior art, for example, methods for treating wastewater containing non-ionic X-ray contrast agents for clinical use. Summary of The Invention The present invention relates to a method for obtaining iodide ions as described in claim 1. As mentioned above, obtaining iodide ions is a key step for recovering iodine from a solution comprising an iodine-containing aromatic compound. The process of the present invention advantageously allows iodide ions to be obtained from a solution comprising a small amount (e.g. the amount described below) of an iodine-containing aromatic compound in an environmentally friendly and providing good yields, which in turn allows for the recovery of iodine. In particular, it has been found that a solution containing small amounts (e.g., amounts) of iodine-containing aromatic compounds can be effectively treated by first adsorbing the iodine-containing aromatic compounds onto activated carbon (preferably using the conditions as described in any of the embodiments disclosed herein), and then directl