Methyl Methacrylate → (Dimethylamino)ethyl methacrylate

Temperature

80 °C

Into a flask equipped with a stirrer, a thermometer and a distilling column are charged 750.8 g of methyl methacrylate, 268.7 g of dimethylaminoethanol containing 0.5% by weight of moisture, and 6.0 g of phenothiazine as a polymerization inhibitor. The mixture is heated with stirring until it boils. The reaction mixture is refluxed until the temperature at the top of the column reaches 95° C., and the azeotropic mixture of methyl methacrylate and water is then distilled at a reflux ratio of 10:1. When the amount of the collected filtrate (methyl methacrylate, water and a small amount of methanol) reaches 55 g, the distillation is stopped. The reaction mixture is then cooled to 80° C. and 7.5 g of di-n-butyltin oxide is added. The resulting mixture is heated until it boils. The azeotropic mixture of the methanol formed and methyl methacrylate is refluxed for 20 minutes, and the reaction mixture is then reacted while part of the azeotropic mixture is withdrawn from the system at a reflux ratio of 15:1. During the reaction, the temperature at the top of the distilling column is kept at 65°-70° C. The esterification reaction is completed in 4.5 hours. The reaction mixture is distilled under reduced pressure as it is to obtain 430.1 g of dimethylaminoethyl methacrylate. This yield corresponds to 91.2% based on the starting dimethylaminoethanol.

1. customInto a flask equipped with a stirrer
2. temperatureThe mixture is heated
3. temperatureThe reaction mixture is refluxed until the temperature at the top of the column
4. customreaches 95° C.
5. distillationis then distilled at a reflux ratio of 10:1
6. distillationthe distillation
7. addition7.5 g of di-n-butyltin oxide is added
8. temperatureThe resulting mixture is heated until it
9. additionThe azeotropic mixture of the methanol
10. customformed
11. customthe reaction mixture is then reacted while part of the azeotropic mixture
12. customis withdrawn from the system at a reflux ratio of 15:1
13. customDuring the reaction
14. customis kept at 65°-70° C
15. customThe esterification reaction
16. distillationThe reaction mixture is distilled under reduced pressure as it

ORD record

ord-1976b31301d544b9b39ed505daea23a1

Source dataset

uspto-grants-1981_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04301297