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. 05, 1992
Filed:
May. 07, 1991
Gyorgy Hidasi, Budapest, HU;
Istvan Szekely, Dunakeszi, HU;
Bela Bertok, Budapest, HU;
Sandor Zoltan, Budapest, HU;
Lajos Nagy, Szentendre, HU;
Antal Gajari, Budapest, HU;
Eva Somfai, Budapest, HU;
Agnes Hegedus, Budapest, HU;
Laszlo Pap, Budapest, HU;
Rudolf Soos, Budapest, HU;
Erzsebet Radvany, Budapest, HU;
Sandor Botar, Budapest, HU;
Tamas Szabolcsi, Budapest, HU;
Chinoin Gyogyszer es Vegyeszeti Termekek Gyara Rt., Budapest, HU;
Abstract
A process is disclosed for preparing a synergistic, crystalline product consisting of solely enantiomer pair 1RCisS and 1SCisR and enantiomer pair 1RTransS and 1STransR of cypermethrin in a 3:7 to 5:5 crystalline mixture, which comprises the steps of: (a) epimerizing an oily melt or a saturated solution of enantiomer pair 1RCisS and 1SCisR and enantiomer pair 1RTransS and 1STransR in a ratio other than 3:7 to 5:5, or a mixture of enantiomer pair 1RCisS and 1SCisR, enantiomer pair 1RTransS and 1STransR together with enantiomer pair 1RCisR and 1SCisS and enantiomer pair 1RTransR and 1STransS, said saturated solution including a protic or apolar, aprotic inert organic solvent by treating said oily melt or saturated solution with an organic or inorganic base at a temperature of -15.degree. C. to 30.degree. C. to precipitate crystals consisting solely of the 1RCisS and 1SCisR and the 1RTransS and 1RTransR enantiomer pairs in a 3:7 to 5:5 weight ratio; (b) isolating the precipitated crystals consisting solely of the enantiomer pairs 1RCisS and 1SCisR and 1RTransS and 1STransR at -10.degree. to 30.degree. C., optionally after inoculating the reaction mixture with a seeding crystal consisting of a mixture of the enantiomer pairs 1RCisS and 1SCisR and 1RTransS and 1STransR at a weight ratio of 3:7 to 5:5 before crystallization; and (c) repeating any of the above steps, if necessary.