Methacrylic Acid → 2-Propenoic acid, 2-methyl-, 2-(2-propen-1-yloxy)ethyl ester

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Reaction Steps

A three-necked flask equipped with stirrer, thermometer, reflux condenser and Dean-Stark trap is charged with methacrylic acid (137.7 g, 1.6 mol), ethylene glycol monoallyl ether (80.7 g, 0.8 mol), p-toluenesulfonic acid (0.76 g, 4.0 mmol) and toluene (650 mL). After allowing the reaction to proceed at 120° C. for 5 hours, 0.12 g of p-toluenesulfonic acid is added, and the reaction is further allowed to proceed at the same temperature for 6 hours. Then, 0.1 g of p-toluenesulfonic acid is added, and the reaction is further allowed to proceed at the same temperature for 9 hours, whereupon the reaction is completed. During the whole reaction period, methacrylic acid and ethylene glycol monoallyl ether are monitored with liquid chromatography. The final conversion amounted to 98%. The reaction mixture is neutralized by adding an aqueous solution of NaHCO3 and allowed to separate into two layers. The aqueous layer is extracted once with toluene. The combined organic layer is dried over CaCl2 and the volatile matter is distilled off under reduced pressure. The crude product is distilled under reduced pressure (60, 2 mmHg) to give 98.7 g (73% yield) of 2-allyloxyethyl methacrylate shown below.

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