Donor Decomposition by Lewis Acids in Ziegler–Natta Catalyst Systems: A Computational Investigation

Progress in propylene homo- and copolymers using advanced transition metal catalyst systems

Recent progress on advanced transition metal catalysts for propylene polymerization and copolymerization are reviewed.

Fundamental aspects of heterogeneous Ziegler–Natta olefin polymerization catalysis: an experimental and computational overview

Using an internal/external donor containing MgCl₂-supported Ziegler–Natta catalyst is one of the important processes for polyolefin production.

Control of Ziegler–Natta catalyst activity by the structural design of alkoxysilane-based external donors

Herein, the evaluation of four commercial alkoxysilanes and two laboratory synthesized novel diethoxysilacycloalkanes as external donors towards propylene polymerization has been done.

Silyl diol ester as a new selectivity control agent in MgCl2-supported Ziegler-Natta systems for propylene polymerization: catalyst structure and polymer properties

In this study, bis(benzoyloxy)dimethylsilane (SDE) was developed as a non-phthalate selectivity control agent (internal donor (ID) and external donor (ED)) in MgCl₂-supported Ziegler–Natta (ZN) systems. The impact of SDE as an ID was investigated in regards to chemical composition, morphology, adsorption behavior (using FTIR spectroscopy, WAXD and SEM studies) and the propylene polymerization performance of the catalyst. The results of the adsorption behavior of SDE revealed that SDE, while able to stabilize the electronically unsaturated surfaces of MgCl₂ [(104) and (110)], has a rather high tendency to be absorbed on strongly acidic Mg ions at the corners of these crystals. The catalyst with optimum SDE content as an ID afforded a system with reasonable activity and isotacticity (even in the absence of ED) along with broader molecular weight distribution (PDI: 6.2–10) and greater flexural modulus than phthalate-based ZN systems. SDE was also used as a new ED in most widely used fourth- and fifth-generation catalyst systems. The results revealed that in fifth-generation catalyst systems, there was an increase in hydrogen response (>40%) along with an increase of activity without any change in the thermal properties of the final polymer in comparison to a conventional ED (alkoxy silane).

In this study, bis(benzoyloxy)dimethylsilane (SDE) was developed as a non-phthalate selectivity control agent (internal donor (ID) and external donor (ED)) in MgCl₂-supported Ziegler–Natta (ZN) systems for polypropylene polymerization.

Accurate experimental and theoretical enthalpies of association of TiCl4 with typical Lewis bases used in heterogeneous Ziegler–Natta catalysis

The enthalpy of association of Lewis bases with TiCl₄ is analyzed using experimental and computational techniques.