Sulfuric Acid → p-Toluenesulfonic acid

Participants

Reaction Conditions

Reaction Steps

560 g of 98% sulfuric acid was dropped into 600 g of toluene with stirring. Then, the temperature was raised at 110 to 120° C. while stirring, reacting for 5 hours. After the reaction, the temperature was decreased while distillation water was added, and upon the temperature reached at about 20° C., a small amount of a crystalline of p-toluenesulfonic acid (4-methylbenzenesulfonic acid) in the system, which was provided in advance, was put therein, generating crystalline deposition of p-toluenesulfonic acid. The crystalline as obtained was collected by filtering, into which distillation water was added. Then, the temperature of the liquid was raised into 60° C. again to dissolve. Then, the temperature was gradually decreased, and upon the temperature reached at about 20° C., a small amount of a crystalline of p-toluenesulfonic acid was added to deposit crystalline. The crystalline was collected by filtering to obtain toluenesulfonic acid in which the para compound was included at 99 mole % in the total of the toluenesulfonic acid. Note that the measurement of the concentration of the para compound was carried out by using HPLC (High Performance Liquid Chromatography) manufactured by Shimadzu Corporation. The same measure was used hereinafter.

Provenance & Evidence