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...

In the previous studies, the several halocarbons (HC) were tested as promoters for a Ti-based Ziegler-Natta (ZN) catalyst at different polymerization conditions. The Results showed that chloro cyclohexane has the best operation in catalyst activity, polymer particle size growth, hydrogen responsibility and wax reduction too. For the first time in this study, the effect of Al/Ti ratio on the opt...

We have been engaged in a search for coordination catalysts for the copolymerization of polar monomers (such as vinyl chloride and vinyl acetate) with ethylene. We have been investigating complexes of late transition metals with heterocyclic ligands. In this report we describe the synthesis of a symmetrical bis-thiadiazole. We have characterized one of the intermediates using single crystal X-r...

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...

Aluminum, the third most abundant element on the earth’s crust, occurs predominantly in oxidic and silicatic minerals. It was first obtained in a pure elemental form by F. Wöhler in 1827 by the reduction of AlCl3 with elemental potassium. In 1859 W. Hallwachs and S. Schafarik synthesized the first organoaluminum compound Et3Al2I3 from elemental Al and EtI, but it took almost 100 years before K....

Polymers can be prepared using chemical and/or electrochemical methods of polymerization (see Chap. 2), although most redox polymers have been synthesized by chemical polymerization. Electrochemically active groups are either incorporated into the polymer structure inside the chain or included as a pendant group (prefunctionalized polymers), added to the polymer phase during polymerization, or ...

Beside Ziegler-Natta and Phillips catalysts the development of methylaluminoxane (MAO) as cocatalyst in combination with metallocenes or other transition metal complexes for the polymerization of olefins has widely increased the possibilities in controlling the polymer composition, polymer structure, tacticity and special properties with high precision. These catalysts allow the synthesis of is...