Method for producing polyalkylene glycoldi(meth)acrylates
The present invention relates to a process for preparing polyalkylene glycol di(meth)acrylates by reacting polyalkylene glycol with (meth)acrylic anhydride, wherein the reaction mixture contains at most 0.5% by weight of metal compounds and/or amines, the reaction is carried out in the presence of polymerization inhibitors and the reaction temperature is at least 60° C.
1. A process for preparing a polyalkylene glycol di(meth)acrylate by reacting a polyalkylene glycol with a (meth)acrylic anhydride, wherein the reaction mixture comprises no metal compound and no amine, the reaction is carried out in the presence of a polymerization inhibitor and the reaction temperature is at least 60° C.
2. The process according to claim 1 , wherein the reaction temperature is in the range from 70° C. to 120° C.
3. The process according to claim 1 , wherein the reaction mixture comprises at least 90% by weight of the polyalkylene glycol and the (meth)acrylic anhydride.
4. The process according to claim 3 , wherein the reaction mixture consists essentially of the polyalkylene glycol, the (meth)acrylic anhydride and a polymerization inhibitor.
5. The process according to claim 1 , wherein the polymerization inhibitor is at least one phenol.
6. The process according to claim 5 , wherein the polymerization inhibitor is hydroquinone monomethyl ether and/or 2,4-dimethyl-6-tert-butylphenol.
7. The process according to claim 1 , wherein the reaction time is in the range of from 1 hour to 24 hours.
8. The process according to claim 1 , wherein the reaction is effected at a pressure in the range of from 500 mbar to 1300 mbar.
9. The process according to claim 1 , wherein said process is performed as a batchwise or semibatchwise process.
10. The process according to claim 1 , wherein the polyalkylene glycol has a weight-average molecular weight in the range from 1000 to 10000 g/mol.
11. The process according to claim 1 , wherein the polyalkylene glycol is polyethylene glycol or polypropylene glycol.
12. The process according to claim 1 , wherein the molar ratio of the (meth)acrylic anhydride to the polyalkylene glycol is in the range of from 4:1 to 2:1.
13. The process according to claim 1 , wherein at least a portion of the polyalkylene glycol is initially charged and heated to the reaction temperature, and the (meth)acrylic anhydride is added to the heated polyalkylene glycol.
14. The process according to claim 1 , wherein the resulting reaction mixture is worked up by adding water.
15. The process according to claim 14 , wherein the weight ratio of reaction mixture to be worked up and water is in the range from 5:1 to 1:5.
16. The process according to claim 14 , wherein the pH is adjusted to a value greater than or equal to 4.5.