2-Propenoic acid, 3-phenyl-, methyl ester → 2-Propenoic acid, 3-phenyl-

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Reaction Conditions

Reaction Steps

100 g of crude methyl cinnamate and 926.8 g of 2.8% caustic soda were placed in a 2-liter flask equipped with a thermometer and a stirrer, and the solution was then stirred at 80° C. for 30 minutes to carry out hydrolysis. An active carbon treatment was omitted. Then, 100 g of toluene was added to this aqueous solution, followed by stirring at 80° C. for 30 minutes. After the stop of the stirring, the solution was allowed to stand and separate and the resultant toluene layer was then removed. The resultant aqueous layer was placed in a 2-liter flask equipped with a thermometer and a stirrer and then maintained at 40° C., and 137.1 g of 25% sulfuric acid was added dropwise to precipitate the crystals of cinnamic acid. After the addition of sulfuric acid had been over, the temperature of the solution was lowered to 20° C., followed by filtering through Nutsche. The resultant filter cake was washed with 1000 g of water, and then vacuum-dried at 50° C. to obtain 87.6 g of cinnamic acid. The purity of cinnamic acid was 97.4%, and the contents of palladium, copper and manganese were 5 ppm or less, 290 ppm, 240 ppm, respectively.

Provenance & Evidence