| abstract |
In the preparation of 2,2-dichloro- and bromocyclopropane compounds by reaction of chloroform or bromoform with an ethylenically unsaturated compound, the reaction taking place in the presence of a solid alkali metal hydroxide and, as a catalyst, a tetraalkylammonium or trialkylsulphonium salt in which the alkyl groups in each case contain 1 to 20 carbon atoms and in which the anion is present as the hydroxide, chloride, bromide, iodide, sulphate or alkylsulphate, the reaction is essentially carried out in the absence of an aqueous phase. By this means, the yield and the reaction rate are increased. |