| 摘要 |
<p>A process for preparing l,l-dihalo-1,2,2,2-tetrafluoroethanes by isomerization of l,2-dihalotetra-fluoroethanes at their reflux temperature, by using, as a catalyst, the reaction product prepared ?in situ? from an anhydrous aluminium halide with at least equimolecular amounts of the isomer l,1-dihalo-1,2,2,2-tetrafluoroethane in a medium consisting of 1,2-dihalotetrafluoroethane. The products find application as intermediates for pyrethroid insecticides.</p> |
