The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 25, 1986
Filed:
Mar. 09, 1984
Chimica del Friuli S.p.A., Torviscosa, IT;
Snia BPD S.p.A., Milan, IT;
Abstract
The invention is concerned with a method of purifying benzoic acid, as obtained by catalytic oxidation of toluene and purification by rectification with the secondary streams being cycled back into the oxidation reactor, characterized in that the secondary streams flowing out of the stripping column undergo the following sequential steps: (a) at least one distillation and at least one crystallization in an organic solvent; (b) scrubbing of the crystals obtained from (a) with the same solvent as in (a); (c) cycling of the mother liquors from crystallization in (a) plus the scrubbing liquors as in (b) back into the dissolver; (d) further scrubbing of the crystals from (b) with the same solvent as in (a) and cycling back of the scrubbing liquors, the crystals scrubbed as in (d) being optionally (d1) further scrubbed with water.