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. Furthermore, 1 g of powdery active carbon (trade name PMSX, made by Toyo Calgon Inc.) was added, and the solution was stirred for 30 minutes and then filtered at 80° C. by the use of Nutsche. Next, 100 g of toluene was added to the resultant filtrate, and the solution was then stirred at 80° C. for 30 minutes, and 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 solution 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 85.4 g of cinnamic acid. The purity of cinnamic acid was 99.9%, and the content of each of palladium, copper and manganese was 5 ppm or less. The recovered active carbon was dried, and metallic components were then measured. As a result, the contents of palladium, copper and manganese were 880 ppm, 8.6 ppm and 5.8%, respectively. In the filtrate and the washing solution with which cinnamic acid had been washed, metallic components of palladium, copper and manganese were each contained in an amount of 5 ppm or less.

Provenance & Evidence