Synthesis
2-Isocyanatoethyl Acrylate is prepared by the reaction of phosgene, ethanolamine and 2-chloropropionyl chloride. The steps are as follows:
In a 500 mL four-necked flask equipped with a stirrer, condenser, thermometer and inner tube, 250 mL of toluene and 25 g (0.41 mol) of 2-aminoethanol were added, heated to 90° C. and supplied with about 20 g of hydrogen chloride gas. Then 56 g (0.44 mol) of 3-chloropropionic acid chloride was added dropwise over 90 minutes and heated at 90° C. for 1 hour. Thereafter, 80 g (0.81 mol) of phosgene was supplied. Dissolved phosgene was then removed by nitrogen gas bubbling. Subsequently, 0.4 g of phenothiazine and 0.4 g of 2,6-bis-t-butylhydroxytoluene were added, and 50 g of triethylamine (0.49 mol) was supplied, and the mixture was heated and stirred at 50° C. for 6 hours. Thereafter, the mixture was cooled to room temperature, the formed hydrochloride salt was filtered, and toluene was distilled off. By the above process, Mixture 2 containing the main product of 2-acryloyloxyethyl isocyanate (AOI) 55 g (0.35 mol) (87% yield) and the by-product of 2-acryloyloxyethyl acrylate (2547 ppm by mass) was obtained.
