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. 21, 1989
Filed:
Oct. 29, 1986
Roger Cocco, Saint-Symphorien D'Ozon, FR;
Rhone-Poulenc Specialites Chimiques, Courbevoie, FR;
Abstract
Essentially pure para-hydroxybenzoic acid crystals, typically containing but trace amounts of inorganic potassium salts and salicylic or 4-hydroxyisophthalic acid, well adopted for foodgrade applications, are facilely recovered from an aqueous solution of dipotassium and/or monopotassium para-hydroxybenzoate by (i) adding an organic solvent for para-hydroxybenzoic acid to such aqueous solution, in an amount sufficient to dissolve the para-hydroxybenzoic acid corresponding to said potassium salts thereof, (ii) next adding thereto an at least stoichiometric amount, relative to said dipotassium and/or monopotassium salt of para-hydroxybenzoic acid, and (iii) separating therefrom an essentially organic phase which comprises said para-hydroxybenzoic acid and an aqueous phase which comprises an inorganic potassium salt.