Cyclopentadienyl-titanium complexes containing –OC6H4X ligands (X = Cl, CH3) activated with methylaluminoxane (MAO) were used in the homo-polymerization of ethylene, propylene, 1-butene, 1-pentene, 1-butene, and 1-hexene, and also in copolymerization of ethylene with the α-olefins mentioned. The -X substituents exhibit different electron donor-acceptor properties, which is described by Hammett’...

the olefins polymerization process in a slurry reactor is discussed. the reaction rate dynamics was analyzed and the contributions of feed flow, gas-liquid mass transfer, polymerization reaction, and catalyst deactivation were estimated. the propylene solubility in a solvent mixture “heptane” was calculated using soave-redlich-kwong equation of state. these data were then approximated by henry-...

the steps taken in designing a loop reactor for bulk propylene polymerization are discussed. the roles played by several parameters like particle growth factor, catalyst activity and solid fraction on reactor volume at different operating conditions are investigated. at first, based on a fixed production capacity and specific rate of catalyst, reactor volume is determined. next, the length and ...

The metal-free polymerization of propylene oxide (PO) using a special class of alkene—N-heterocyclic olefins (NHOs)—as catalysts is described. Manipulation of the chemical structure of the NHO organocatalyst allows for the preparation of the poly(propylene oxide) in high yields with high turnover (TON>2000), which renders this the most active metal-free system for the polymerization of PO repor...

A pilot-scale fluidized bed reactor was built and used to study and gain a better understanding of the propylene polymerization process at conditions similar to those of industrial fluidized-bed reactors. Propylene polymerization reaction was carried out continuously in the reactor and dynamic temperatures, and propylene and hydrogen concentrations data were collected. Simulated dynamic profile...

This review article describes developments in chiral metallocenes as polymerization catalysts focusing on C2 symmetric ansa-zirconocene complexes. Selective synthesis of rac-isomers of ansa-zirconocenes are surveyed. Isospecific polymerizations of propylene catalyzed by chiral zirconocenes are summarized. Advanced series of polymerizations by chiral metallocenes such as asymmetric polymerizatio...

In this work, we studied propylene polymerization using some α-diimine palladium catalysts with systematically varied ligand sterics. In propylene polymerization, the ligand steric effect exhibits significant variations on the catalytic activity, polymer molecular weight, and branching density. However, the regio control for the polymer microstructure is poor. Furthermore, copolymerization of 1...

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...