Ethene oligomerization kinetics on a nickel(II)-exchanged silica-alumina catalyst were determined using a mechanically stirred laboratory-scale slurry reactor. With analysis of both gaseous and liquid outlets from the reactor, the various reaction rates could be correlated in terms of liquid-phase reactant concentrations. In addition, vapour-liquid equilibria could be measured. All experiments were carried out at an operating pressure of 3.5 MPa and the temperature was varied between 120 and 180 degreesC, The feed MHSV was varied between 1 and 12, Three second-order reactions were used to correlate the observed rate of ethene conversion and the Schulz-Flory-type product distribution: ethene-ethene dimerization, ethene-oligomer reaction, and butene-butene dimerization. The inferred rate of butene dimerization was confirmed experimentally using butene as the reactant feed, Very little deactivation was observed during experimental runs lasting 900 h or more, with conversions being maintained throughout at over 908. Oligomers up to C-16 were obtained, The absolute rate of ethene oligomerization typically exceeded 11.5 g g(cat)(-1), h(-1). It was shown experimentally that both gas-liquid and interparticle mass transfer limitations were absent in this work. (C) 2000 Academic Press.