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:
Dec. 02, 2008
Filed:
Mar. 14, 2008
Hidetoshi Nakayasu, Shizuoka, JP;
Yasuhiro Mizuno, Shizuoka, JP;
Hideyuki Hongo, Shizuoka, JP;
Takasago International Corporation, Tokyo, JP;
Abstract
Crude menthol is dissolved in nitrile series solvent and then menthol is precipitated by cooling the solution to thereby obtain optically and chemically substantially pure menthol, the enantiomeric excess thereof being more than about 99% e.e. and the chemical purity being more than about 99%. Preferred examples of the nitrile series solvent include acetonitrile and propionitrile. The dissolution of crude menthol is carried out at a temperature below 42° C., which is the melting point of menthol. The cooling temperature in crystallization is preferably at a room temperature or a little lower temperature than the room temperature. After crystallization of menthol, additional purification process such as a distillation may be conducted, if necessary.