An analysis of the initial rates of reaction was carried out of the aluminium bromide catalyzed isomerization of 1-propyl bromide: I-C3H7Br + Al2Br6 = 2-C3H7Br + Al2Br6 The proposed kinetics of the process is consistent with a nucleophilic displacement of the aliphatic bromine contained in complexes of the alkyl bromide with aluminium bromide. The displacement, initiated by the AlBrt ion. is accompanied by a rate determining 2,1 hydride shift. (c) 2005 Elsevier B.V. All rights reserved.