Estimation of Reactivity Ratios for Olefin Polymerization Catalysts—On the Importance of Thermodynamics

Abstract A systematic study of the impact of gas phase composition on the estimation of the reactivity ratios of a Ziegler–Natta catalyst during the gas phase copolymerization of ethylene with 1‐butene and 1‐hexene has been carried out. The results of the study show that if one uses a realistic equation of state to estimate the co‐ and anti‐solubility effects of multiple species in the gas phase, one can obtain a unique value of the reactivity ratio pair from any number of experiments. However, it is found that using only binary solubility data and ignoring the impact of chemically inert species on solubility will lead to the estimate of composition‐dependent reactivity ratio pairs.