公开(公告)号：DK112034B

公开(公告)日：1968-11-04

申请号：DK330759

申请日：1959-09-17

Applicant: SNIA VISCOSA

Inventor： MUENCH W ,  NOTARBARTOLO L ,  SILVESTRI G

IPC: C07D41/06

公开(公告)号：SE314665B

公开(公告)日：1969-09-15

申请号：SE1088762

申请日：1962-10-10

Applicant: SNIA VISCOSA

Inventor： MUENCH W ,  MATTONE R ,  NOTARBARTOLO L ,  MESSINA G

IPC: C07C51/265 ,  C07C51/42 ,  C07C51/46 ,  C07C63/06

Abstract: In the manufacture of purified benzoic acid from raw materials obtained by the oxidation of toluene, the raw material is treated with water in more than a sufficient amount to form an azeotrope mmixture with all the unreacted toluene, and the azeotrope and some of the excess water are then distilled off, preferably at a temperature above the boiling point of the azeotrope, e.g. at 90-95 DEG C. Preferably, the amount of water added is such that an aqueous solution of benzoic acid of 3-5% concentration is obtained after the toluene-water azeotrope and excess water have been distilled off, and the benzoic acid solution is then freed from resinous impurities by decantation, which may be repeated. Finally, the benzoic acid is crystallized and centrifuged. The mother liquor from the crystallization is used to scrub the toluene-water azeotrope, and the azeotrope is then passed to a separator from which toluene is returned to the oxidation vessel and the aqueous layer is returned to the still in which the azeotropic distillation is effected. The process is particularly applicable to the products obtained by oxidizing toluene with air at a raised temperature, e.g. 145 DEG C., in the presence of an oxidation catalyst, e.g. cobalt enanthate.