the effects of temperature, time and the strategy of prepolymerization were studied on the morphology of polypropylene particles. propylene polymerization was carried out in slurry phase using 4th generation of ziegler-natta catalyst, cyclohexylmethyl dimethoxysilane as external electron donor, and triethyl aluminum as co-catalyst. prepolymerizations were carried out based on two strategies: is...

Ab initio SCF-LCAO-MO all-electron calculations have been performed for the catalyzed reaction, related to the Ziegler-Natta polymerization process TiCl.·Al(CH3)3+C2H. -+TiCl •. Al(CH3h·C3H7. The energy of the Ti-Al--ethylene complex during the reaction pathway is associated to the following processes: First, the ethylene coordinates to the catalyst complex and subsequently it reacts with the m...

Chapter 1 Motivated by the isolobal and isoelectronic relationship between the do CpW(CR) fragment and the do bent metallocene core, the synthesis and reactivity of alkyl complexes of the type CpW(CAd)R 2 (Ad = 1-adamantyl; R = alkyl, Cl, NMe 2 ) are presented. AdCN reacts with W2 (OCMe3 )6 to provide W(CAd)(OCMe 3)3, from which CpW(CAd)C12 may be prepared in three steps. Alkylation of CpW(CAd)...

Magnesium alkyls such as butyl octyl magnesium and ethyl are used precursors for highly active water-free chloride support materials Ziegler–Natta catalysts. These show a high viscosity in hydrocarbon solvents which negatively affect their industrial application. Density functional theory (DFT) calculations supported the hypothesis that can form oligomeric chain structures responsible viscosity...

Understanding the structure and properties of MgCl2/TiCl4 nanoclusters is a key to uncovering origin Ziegler–Natta catalysis. In particular, vibrational spectroscopy can sensitively probe morphology active species MgCl2/TiCl4. Here, we determined spectroscopic fingerprints 50MgCl2 50MgCl2/3TiCl4 which were obtained by nonempirical determination based on an evolutionary algorithm DFT. The adsorp...

in ziegler-natta olefin polymerization, the pore architecture of catalysts plays a crucial role in catalyticperformances and polymer properties. while the type of preparation routes (such as chemical reaction andsolution precipitation) greatly affects the catalyst pore architecture as a result of different solidification mechanisms,the modification of the pore architecture within a given route ...