To provide a method for purifying benzoic acid by which the high- purity benzoic acid can efficiently and continuously be obtained with relatively simple equipment.
A crystal of crude benzoic acid having a bulk density regulated to ≥0.2g/cm3 and an average grain diameter regulated to ≥0.3mm is charged from a raw material charging port 1 in the upper part of a continuous crystallizer equipped with a stirrer 5 and brought into countercurrent contact with a melt produced by melting the settled crystal with a heating means 3 provided in the lower part and purified. The purified benzoic acid is then taken out of a product takeout port 4 in the lower part as a melt. The mother liquor is taken out of a mother liquor takeout port 2 in the upper part to thereby continuously afford the purified benzoic acid of ≥99.9% purity.
ARIFUKU YUJI
HORIBE KAZUYOSHI
NOMA NAGAMASA
TAKEUCHI MASAKAZU
KONO HARUKI
Next Patent: (METH)ACRYLIC ESTER AND ITS PRODUCTION