This paper describes the development of a so-called single event kinetic model for butane isomerization and its application. From the experimental programme followed that butane isomerization occurs via a bimolecular rather than via a monomolecular mechanism. A reaction network is generated using a computer algorithm because of the numerous species and reactions involved. Kinetic equations are constructed using the generated reaction network and the values of the kinetic parameters are estimated using experimental data obtained on a Pt/chlorinated alumina catalyst. Adaptation of a posteriori lumping to the C4 isomerization specificity leads to a rewriting of the rate equations with only 4 intrinsic kinetic parameters between 4 lumps with any loss of information of the elementary step reaction network. (C) 2004 Elsevier Ltd. All rights reserved.