Fluorination of acrylate esters and derivatives
View Patent ↗The present invention generally relates to processes for converting acrylate esters or a derivative thereof to difluoropropionic acid or a derivative thereof. This process is generally performed using fluorine gas in a hydrofluorocarbon solvent.
1. A process for fluorinating a double bond comprising:
forming a reaction mixture comprising a hydrofluorocarbon or fluorocarbon solvent, fluorine gas, and a compound of formula 1
wherein R 1 is hydroxy, alkoxy, chloro, or —OC(O)CH═CH 2 to form a compound of formula 2 in a yield of at least 50%
wherein R 2 is hydroxy, alkoxy, chloro, —OC(O)CHFCH 2 F.
2. The process of claim 1 wherein R 1 is methoxy.
3. The process of claim 1 wherein R 1 is hydroxy.
4. The process of claim 1 wherein R 1 is chloro.
5. The process of claim 1 wherein R 2 is methoxy.
6. The process of claim 1 wherein the hydrofluorocarbon or fluorocarbon solvent has a melting point less than about −20° C. and a boiling point greater than about 30° C.
7. The process of claim 1 wherein the hydrofluorocarbon or fluorocarbon solvent is 2H,3H-decafluoropentane, eicosafluorononane, tetradecafluorohexane, tetradecafluoro-2-methylpentane, hexafluorobenzene, octadecafluorodecahydronaphthalene, octadecafluorooctane, octafluorocyclopentene, octafluorotoluene, perfluoro(1,3-dimethylcyclohexane), perfluoroheptane, perfluoro(2-butyltetrahydrofuran), perfluorotriethylamine, heptacosafluorotributylamine, tetradecafluoromethylcyclohexane, 1,1,1,3,3-pentafluorobutane, or a combination thereof.
8. The process of claim 7 wherein the hydrofluorocarbon solvent is 2H,3H-decafluoropentane.
9. The process of claim 7 wherein the reaction mixture has a temperature from about −80° C. to about −20° C.
10. The process of claim 1 wherein the reaction mixture further comprises a fluorination additive and the fluorination additive is an alcohol, an acid, or a combination thereof.
11. The process of claim 10 wherein the fluorination additive is the alcohol, and the alcohol comprises ethanol, methanol, trifluoroethanol, or a combination thereof; or the fluorination additive is the acid, and the acid comprises triflic acid, trifluoroacetic acid, sulfuric acid, formic acid, acetic acid, or a combination thereof.
12. The process of claim 1 wherein the process is a continuous process and the infusion rate of the compound of formula 1 is from about 0.2 to about 2 mL/minute.
13. The process of claim 7 further comprising contacting the compound of formula 2 with an alcohol and a catalyst, wherein the catalyst is a Brønsted acid or a Lewis acid.