Phthalic Acid → N-Isopropylaniline

Participants

Reaction Conditions

Reaction Steps

N-isopropylaniline is synthesized as follows: A mixture of 233 g. (2.5 moles) of aniline, 5 l. of tetrahydrofuran and 250 ml. of acetone is stirred at 24°-25° C. under nitrogen for 2 hours and coooled to 10° C., 675 g. (4.06 moles) of phthalic acid is added rapidly, the resulting suspension is stirred at 10° C. under nitrogen, and 100 g. (2.64 moles) of powdered 98% sodium borohydride is added over a period of 25 minutes with stirring under nitrogen, during the course of which the temperature rises to 28° C. The reaction mixture is stirred under nitrogen at 28° C. for 15 minutes and at 60°-61° C. for 2 hours, cooled to 25° C. and siphoned portionwise into 2.0 l. of 20% sodium hydroxide solution at a rate such that the temperature does not exceed 20° C. The organic phase is separated, 1.0 kg. of anhydrous potassium carbonate is added, the mixture is stirred at 20°-25° C. for 20 minutes, the solid is removed by filtration and washed twice with 250 ml. portions of tetrahydrofuran, the washings are combined with the filtrate, and the tetrahydrofuran is distilled at 20-100 mm. Hg. and a maximum temperature of 55° C. The resulting residual oil is fractionally distilled through a 35 cm. Vigreux column to obtain the 97.4% pure product (295 g. (84.4%)). B.p. 62°-64° C./1 mm. Hg.

Provenance & Evidence