Tetrabutylammonium → 2-Phenylethyl methacrylate

Participants

Reaction Steps

To a solution of 4.86 g (5.52 mL, 21.0 mmol) of 1-(2-dimethylamino-ethoxy)-1-trimethyl-siloxy-2-methyl-1-propene, 0.1 mL of tetrabutylammonium biacetate hexahydrate (0.04M in THF) in 30 mL of THF was added a mixture of 6.6 g (7.1 mL, 42 mmol) of 2-dimethylaminoethyl methacrylate (purified by distillation and passage over a column of basic alumina under argon), and 31.6 g (31.6 mL, 168 mmol) of 2-phenylethyl methacrylate (purified by passage over a column of basic alumina under argon) from an addition funnel. The temperature of the reaction mixture rose to 62° C. during the course of the addition, and an ice bath was used to moderate the temperature rise. When, following the conclusion of the addition, the temperature was 26° C., the dropwise addition of 43.2 g (49 mL, 273 mmol) of trimethylsilyl methacrylate was begun. During the course of the addition the temperature of the reaction mixture rose to 45° C. while a total of 1.25 mL of tetrabutylammonium biacetate hexahydrate (0.04M in THF) was added in 9 additions. Analysis of an aliquot of the solution by 1H NMR showed that there was no residual monomer present. After addition of 55 mL of THF, 56 mL of methanol, and 0.086 g (2.7 mmol) of tetrabutylammonium fluoride trihydrate the solution was refluxed for 9 hr. Then 50 mL of THF was added, and refluxing was continued for an additional 9 hr. The solution was evaporated under reduced pressure with a rotary evaporator. The solid residue was dried in a vacuum oven at 80° C. for 8 hr to give 57 g of poly ω-2-β-dimethylaminoethyl isobutyrate(2-dimethylaminoethyl methacrylate [9 mol %]-co-2-phenylethyl methacrylate [35 mol %]-b-methacrylic acid [56 mol %]) 1H NMR analysis of the polymer showed that virtually no trimethylsilyl groups remained.

Provenance & Evidence