How can pH value during catalyst preparation affect the performance of vanadium-modified (SiO2/MgO/ MgCl2)•TiClx Ziegler-Natta polyethylene catalysts

Determination of titanium and vanadium in Ziegler-Natta catalysts by inductively coupled plasma atomic emission spectrometry.

A method for the determination of Ti and V using inductively coupled plasma atomic emission spectrometry (ICP OES) in Ziegler-Natta polymerization catalysts is proposed. The concentrations of both Ti and V are efficiently determined after catalyst acid digestion with a mixture of HNO3 + HCl + HF and heating (160 degrees C for 6 h) or with 10% (v/v) H2SO4 and heating (160 degrees C for 6 h) or w...

The coordinative state of aluminium alkyls in Ziegler-Natta catalysts.

The most commonly used cocatalyst species in Ziegler-Natta catalysts are aluminium alkyls. In this study we aim to find the interaction between aluminium centres of these activators and other components in the ZNC system. Initially we look at binary systems of Al-alkyl/MgCl2 and ternary systems of Al-alkyl/MgCl2/TiCl4, followed by donor containing systems. The aluminium alkyls prove to be very ...

Preparation of Ultra High Molecular Weight Polyethylene Using Ziegler-Natta Catalyst System: Optimization of Parameters by Response Surface Methodology

Ziegler-Natta catalysts for propylene polymerization – Interaction of an external donor with the catalyst

The interaction of the external donor (propyltrimethoxysilane - PTMS) with titanium-magnesium catalysts (TMCs) containing dibutylphthalate (DBP) as internal donor, which were prepared in different ways, was studied by chemical analysis and infrared diffuse reflectance spectroscopy (DRIFTS). The chemical composition of the catalysts after their interaction with heptane solutions of PTMS, PTMS/Al...

Imido-modified SiO2-supported Ti/Mg Ziegler-Natta catalysts for ethylene polymerization and ethylene/1-hexene copolymerization

A novel imido-modified SiO2-supported Ti/Mg Ziegler-Natta catalyst for ethylene and ethylene/1-hexene polymerization is investigated. The catalyst is prepared by modification of (SiO2/MgO/MgCl2)TiClx Ziegler-Natta catalysts via supporting vanadium species followed by reaction with p-tolyl isocyanate as imido agents, to get the merits from both the SiO2-supported imido vanadium catalyst and the ...

Design of stereoselective Ziegler-Natta propene polymerization catalysts.

After five decades of largely serendipitous (albeit formidable) progress, catalyst design in Ziegler-Natta olefin polymerization, i.e., the rational implementation of new active species to target predetermined polyolefin architectures, has ultimately become a realistic ambition, thanks to a much deeper fundamental understanding and major advances in the tools of computational chemistry. In this...