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

Participants

Reaction Conditions

Reaction Steps

100 g of crude methyl cinnamate, 926.8 g of 2.8% caustic soda and 100 g of toluene 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. After the stop of the stirring, the solution was allowed to stand and separate at 80° C. and the resultant toluene layer was then removed. 1 g of powdery active carbon (trade name PMSX, made by Toyo Calgon Inc.) was added to the aqueous layer, and the solution was stirred for 30 minutes and then filtered at 80° C. by the use of Nutsche. The resultant filtrate 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 84.9 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 960 ppm, 8.5% and 5.5%, 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