Ethanol → p-Cyanobenzamide

Terephthalonitrile (64 g, 0.5 mol) and ethanol (850.3 g) were placed in a 2 L four-neck flask, and the resultant mixture was heated to 78° C. with stirring. To the mixture, a 20% aqueous solution (20 g) of sodium hydroxide was added over six hours by use of a tube pump. After the reaction was completed, liquid chromatographic analysis revealed that the reaction mixture contained 48.2 g of p-cyanobenzamide (yield 66%) and 7.4 g of p-cyanobenzoic acid (yield 10%). The reaction mixture was cooled to 30° C., neutralized with concentrated sulfuric acid, and concentrated under reduced pressure so as to remove 508 g of ethanol. After the pressure was restored to normal pressure, the mixture was heated again to 78° C., and a 20% hydrochloric acid/ethanol solution (162.4 g) which was prepared in advance was added to the mixture over six hours by use of a tube pump. The mixture was further stirred for six hours with heat. Gas chromatographic analysis revealed that the reaction mixture contained 65.6 g of ethyl p-cyanobenzoate (yield 75%, based on terephthalonitrile) and diethyl terephthalate (yield 10%, based on terephthalonitrile). After the reaction mixture was cooled to 30° C., the mixture was neutralized with an aqueous solution of sodium hydroxide, and precipitated inorganic salt crystals were collected through filtration. After the filtrate was concentrated and water (350 g) was added thereto, the filtrate was dissolved with heat, and then cooled to 8° C. so as to reprecipitate crystals, to thereby obtain 53.6 g of ethyl p-cyanobenzoate (purity 98.0%) The obtained crude crystals were recrystallized from a solvent of a mixture of water (120 g)/ethanol (120 g), to thereby obtain 46.6 g of ethyl p-cyanobenzoate crystals (purity 99.5%; yield 53%, based on terephthalonitrile).

ORD record

ord-a6aac18c2e6148e3b8ee4caa33e8c96e

Source dataset

uspto-grants-2002_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06433211B1