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Method for the restabilization of (meth)acrylic monomers
US9422221B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-9422221-B2 |
| Application number | US-201013375109-A |
| Country | US |
| Kind code | B2 |
| Filing date | May 31, 2010 |
| Priority date | Jun 8, 2009 |
| Publication date | Aug 23, 2016 |
| Grant date | Aug 23, 2016 |
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Abstract
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A process for replacing the stabilization of (meth)acrylic monomers, wherein phenothiazine is removed from phenothiazine-containing (meth)acrylic monomers by adsorption on activated carbon, and then a moderately active polymerization inhibitor is optionally added.
First claim
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The invention claimed is: 1. A process for removing phenothiazine from a (meth)acrylic monomer, comprising: removing phenothiazine from a phenothiazine-containing (meth)acrylic monomer by adsorption on activated carbon, and adding a moderately active polymerization inhibitor to the (meth)acrylic monomer after adsorption, wherein the moderately active polymerization inhibitor is a phenolic compound or a quinone, wherein a content of the phenothiazine in the (meth)acrylic monomer after adsorption is less than 10 ppm. 2. The process of claim 1 , wherein a BET surface area of the activated carbon is from 200 to 3000 m 2 /g. 3. The process of claim 2 , wherein the BET surface area of the activated carbon is from 300 to 2000 m 2 /g. 4. The process of claim 1 , wherein the activated carbon is molded carbon, granular carbon or pulverized carbon. 5. The process of claim 1 , wherein the content of the phenothiazine in the (meth)acrylic monomer after adsorption is less than 5 ppm. 6. The process of claim 1 , wherein the moderately active polymerization inhibitor is hydroquinone monomethyl ether. 7. The process of claim 1 , wherein a content of moderately active polymerization inhibitor is up to 100 ppm. 8. The process of claim 1 , wherein a content of moderately active polymerization inhibitor is around 50 ppm. 9. The process of claim 1 , wherein the (meth)acrylic monomer is a (meth)acrylic acid. 10. The process of claim 9 , wherein the (meth)acrylic monomer is an acrylic acid. 11. The process of claim 10 , wherein a water content of the acrylic acid is from 40 to 75% by weight. 12. The process of claim 10 , wherein the acrylic acid is anhydrous. 13. The process of claim 10 , wherein from 20 to 95 mol % of acid groups of the acrylic acid are neutralized. 14. The process of claim 10 , wherein acid groups of the acrylic acid are unneutralized. 15. The process of claim 10 , wherein from 40 to 75 mol % of acid groups of the acrylic acid are neutralized. 16. The process of claim 10 , further comprising: polymerizing the acrylic acid after adsorption, to obtain a superabsorbent polymer. 17. The process of claim 1 , wherein removing phenothiazine comprises a fixed bed process. 18. The process of claim 1 , further comprising regenerating the activated carbon.
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- What does patent US9422221B2 cover?
- A process for replacing the stabilization of (meth)acrylic monomers, wherein phenothiazine is removed from phenothiazine-containing (meth)acrylic monomers by adsorption on activated carbon, and then a moderately active polymerization inhibitor is optionally added.
- Who is the assignee on this patent?
- Herfert Norbert, Hammon Ulrich, Wuestefeld Renate, and 1 more
- What technology area does this patent fall under?
- Primary CPC classification C07C51/47. Mapped technology areas include Chemistry & Metallurgy.
- When was this patent published?
- Publication date Tue Aug 23 2016 00:00:00 GMT+0000 (Coordinated Universal Time) (B2). Legal status and post-grant events are not shown on this page.
- What related patents are in patentsdb?
- We list 8 related publications on this page (citations in our corpus or others sharing the same primary CPC).