Catalytic making of ethylene-1-hexene elastomers: Thermodynamic guide to process development

Ethylene-alpha olefin elastomers have versatile applications. Solution copolymerization makes them, using ethylene and alpha olefin-rich comonomer feed and metallocene and postmetallocene precatalysts, at laboratory and industry conditions. Hence, this study models ethylene solubility in toluene-1-hexene and n-hexane-1-hexene mixtures using VLE criterion, Peng–Robinson EoS, vdW1f mixing rule, and Shulgin's activity coefficient-Henry's constant formalism. Levenberg–Marquardt algorithm, with initial conditions comprising quasi-ideal K factor correlation and Tait liquid phase EoS, solved the model equations. This eliminates present cumbersome literature approach. The predicted solubilities well match the experimental values at all temperature and pressure. Ethylene solubility correlates the liquid phase fluid compressibility to the corresponding catalyst active center residential environment. This offers a new approach to investigate catalyst and copolymerization phenomena and develop ethylene-1-hexene elastomer process. Evaluating copolymerization and microstructural property, using ethylene solubility ignoring that in 1-hexene, introduces significant errors. The present work corrects them and solves a long-standing polymer reaction engineering problem.