Preparation of inorganic MgCl2-alcohol adduct and its application in organometallic HYBRID catalysts for ethylene polymerization

From Multisite Polymerization Catalysis to Sustainable Materials and All-Polyolefin Composites

“…Following the discovery of highly active and stereospecific Lewis-base-modified MgCl 2 -supported TiCl 4 by Montecatini and Mitsui Chemical in 1968, remarkable progress has been made in catalyst and process development, including tailoring of multisite catalysts. Thus, the eco-, resource-, and energy-efficiency of solvent-free polyolefin production have been substantially improved by eliminating numerous process steps such as removal of catalyst residues (deashing), solvent recovery, separation of wax-like byproducts, and even pelletizing extrusion when using particle-forming spherical catalysts. ,, For further improving MWD control and reactor blend formation, conventional supported Ziegler–Natta catalysts are equipped with single-site catalyst components to produce a wide range of Ziegler–Natta hybrid catalysts. ,− Ziegler–Natta hybrid catalysts, in particular, combine the exceptional morphology control typical of spherical MgCl 2 -supported Ziegler–Natta catalysts with the unique control of polyolefin molecular architectures typical of metallocenes . For instance, spherical polypropylene, produced by MgCl 2 , is used as a support for single-site catalysts to produce Ziegler–Natta hybrid catalysts that, in contrast to multisite catalysts, contain just one single-site catalyst component.…”

Genesis of MgCl2‐based Ziegler‐Natta Catalysts as Probed with Operando Spectroscopy

“…[89] In the n(CH x ) region, the bands due to the asymmetric and symmetric n(CH 3 ) modes are more spaced to each other (at 2960 and 2795 cm À1 ) because of the interaction with the Cl À counterions, and three new bands are present at 2980, 2867 and 2750 cm À1 . [92] Finally, it should be also noted that a weak band at 1620 cm À1 starts growing during the first steps of the dealcoholation, but rapidly decreases at temperatures above 120 8C. [90,91] During the dealcoholation process, the n(OH) band reduces in intensity and progressively shifts up-ward to ca.…”

Dynamics and stability of ethylene polymerization in multizone circulating reactors

“…The temperature of the gas-solid mixture at the feed line, (10) considers the contribution of the enthalpies at the downer bottom and the cooled recycled gas temperature T R (11) where V hex is the heat exchanger volume, A R is the cross sectional area of the reactor.…”

“…The reaction begins by the formation of active sites, which is assumed to take place in excess of cocatalyst [6,[9][10][11][12]. This reaction is followed by an initiation reaction, in which the monomer gases and the active sites are combined to form live polymers.…”