Principal kinetic data are presented for ethylene homopolymerization and ethylene/1-hexene copolymerization reactions with two types of chromium oxide catalyst The reaction rate of the homopolymerization reaction is first order with respect to ethylene concentration (both for gas-phase and slurry reactions); its effective activation energy is 10.2 kcal/mol (42.8 kJ/mol). The r(1) value for ethylene/1-hexene copolymerization reactions with the catalysts is similar to 30, which places these catalysts in terms of efficiency of alpha-olefin copolymerization with ethylene between metallocene catalysts (r(1) similar to 20) and Ti-based Ziegler-Natta catalysts (r(1) in the 80-120 range). GPC, DSC, and Crystaf data for ethylene/1-hexene copolymers of different compositions produced with the catalysts show that the reaction products have broad molecular weight and compositional distributions. A combination of kinetic data and structural data for the copolymers provided detailed information about the frequency of chain transfer reactions for several types of active centers present in the catalysts, their copolymerization efficiency, and stability. (C) 2008 Wiley Periodicals, Inc.