Propene was oligomerized at 5000 kPa and 250 degrees C at 5 and 50% conversion. Equilibrium concentrations for the hexene isomers were predicted using data from various sources. The data from the NBS gave the best equilibrium prediction. Comparsions between the low and high conversion results and also with equilibrium predictions indicate that at low conversions the system attains equilibrium with respect to double bond isomerization but not with respect to the skeletal structures. At the low conversion conditions chosen only oligomerization reactions occurred. All this supports the development of a model for oligomerization based on skeletal groups at each carbon number.