MIXED STEREOISOMERS OF FENVALERATE

摘要

A new form of an enantiomer pair of stereoisomers of fenvalerate comprising (S)- alpha -cyano-3-phenoxybenzyl(S)-2-(4-chlorophenyl)isovalerate and the (R)-(R) enantiomer as a crystal of characteristics: crystal system: monoclinic lattice constants: a = 11.90 ANGSTROM , b = 5.60 ANGSTROM , c = 32.58 ANGSTROM , beta = 93.0 DEG space group: P2 1/c density: 1.28 g/cm<3> number of molecules in unit lattice: 4. A process of preparing the enantiomer pair or the fenvalerate rich in the enantiomer pair comprises depositing said crystals from a solution of a racemate of fenvalerate. Another process of preparing the enantiomer pair comprises depositing the crystals from a solution of the fenvalerate rich in the enantiomer pair and separating the crystals from the liquor.