Résumé : The SN2 reaction between potassium iodide and n‐propyl, allyl and propargyl halides, in anhydrous acetone, has been studied kinetically. The following Arrhenius parameters have been found: n‐propyl bromide E : 17,59 log PZ : 10,17 allyl bromide E : 15,34 log PZ : 10,28 propargyl bromide E : 16,81 log PZ : 11,63 allyl chloride E : 18,82 log PZ : 10,17 propargyl chloride E : 19,88 log PZ : 11,21 Copyright © 1955 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim