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:
May. 26, 1981
Filed:
Jun. 13, 1979
Richard P Carr, Cincinnati, OH (US);
Ashok K Nanda, Cincinnati, OH (US);
Charles A Schneider, Villa Hills, KY (US);
Girish K Malhotra, Cincinnati, OH (US);
The Sherwin-Williams Company, Cleveland, OH (US);
Abstract
A method for purifying a triazole composition is disclosed. The method involves the steps of producing a substantially anhydrous slurry in an alcohol of an alkali metal or of an alkaline earth metal salt of the triazole to be purified, separating solids from the slurry and washing the solids with an alcohol. A preferred method includes the steps of charging to a suitable vessel a crude triazole, a substantially equivalent amount of sodium hydroxide, added to an aqueous solution, hexanol or another alcohol having comparatively low water solubility, and xylene or another inert solvent; water is then removed from the system by azeotropic distillation to produce the desired slurry. When the triazole is benzotriazole or any given tolyltriazole isomer, the purified triazole can merely be recovered from the dried solvent system by filtration, washed (usually with a mixture of fresh solvent of the same identity as that from which it had been filtered) and dried. When the triazole to be purified is a blend of the 4- and 5-tolyltriazole isomers, a method for producing fractions enriched in each of the two isomers (subsequently defined) is also disclosed. This latter method involves all of the steps described above, including recovery of the precipitate, washing and drying; in this instance, the precipitate is found to be substantially enriched, by comparison with the isomer mixture charged, in 5-tolyltriazole, while most of the 4-tolyltriazole remains dissolved in the filtrate.