Ethylene polymerization with a nickel diimine catalyst covalently anchored on spherical ZSM-5

Abstract

Late transition catalysts play an important role in the catalytic conversion of olefins into polymers with different microstructures.

Synthesis and Characterization of Fe-Substituted ZSM-5 Zeolite and Its Catalytic Performance for Alkylation of Benzene with Dilute Ethylene

“…Such low and broad decomposition temperatures seem to suggest that this weight-loss event is not associated with the formation of true coke, rather it is likely due to the desorption or oxidation of other chemical species formed during reaction testing. As established, the [Fe]-ZSM-5 catalyst has significantly lower strength of its strong acid sites, which is believed to promote the polymerization of olefins. , These polymerized olefins could be adsorbed strongly onto the weaker strength acid sites of the catalyst, thus inhibiting the benzene alkylation reaction, as exactly observed experimentally. , This also explains the low weight-loss temperatures observed for the spent [Fe]-ZSM-5 catalyst, as they are associated with the desorption or oxidation of the polymerized olefins rather than the oxidation of coking carbon, as in the case of the spent ZSM-5 catalyst. This also suggests that adsorption of the polymerized olefins was the main cause of fast deactivation of the [Fe]-ZSM-5 catalyst rather than coking.…”

“…As established, the [Fe]-ZSM-5 catalyst has significantly lower strength of its strong acid sites, which is believed to promote the polymerization of olefins. 51,52 These polymerized olefins could be adsorbed strongly onto the weaker strength acid sites of the catalyst, thus inhibiting the benzene alkylation reaction, as exactly observed experimentally. 53,54 This also explains the low weight-loss temperatures observed for the spent [Fe]-ZSM-5 catalyst, as they are associated with the desorption or oxidation of the polymerized olefins rather than the oxidation of coking carbon, as in the case of the spent ZSM-5 catalyst.…”

Catalytic Transformation Conditions of Ethanol on Dealuminated BEA Zeolites

“…[3][4][5] Brazil is one of the global leaders in ethanol production, and the building of large-scale plants for the manufacture of polyethylene and other polymers from ethanol is an effective low-carbon-footprint alternative to steam cracking of hydrocarbons. [6][7][8][9] Intramolecular dehydration to ethylene and intermolecular reaction to derive diethyl ether can take place in a competitive way during ethanol dehydration, diethyl ether being favored at low temperatures, and ethylene being favored at high temperatures. 10 Literature reviews [11][12][13] indicate that higher conversions and better catalytic stability can be obtained for dealuminated zeolites due to the tuning of hydrophobicity, diffusion effect and acidity.…”

Emulsion Polymerization Strategy for Heterogenization of Olefin Polymerization Catalysts

“…The Ni complexes ( Ni1 – Ni3 ) were synthesized by reactions of the ligands with Ni precursors (Scheme ). − These Ni complexes were characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and elemental analyses. These complexes will be used as precatalysts in homogeneous polymerization for comparison.…”

“…In the past 30 years, hundreds of homogeneous late-transition-metal-based olefin polymerization catalysts have been reported. − However, very few heterogeneous catalysts have been studied for the copolymerization of ethylene with polar comonomers. − Industrial polyolefin processes mainly use heterogeneous systems because of their great advantages in product morphological control, avoidance of reactor fouling, and stable production operations. − This represents one of the key challenges for the successful commercialization of late-transition-metal catalysts. Heterogenization of homogeneous metal catalysts on solid supports has been widely studied for catalytic organic reactions − and represents a promising strategy to address the above issue. − This is usually achieved via two methods: (a) combination of a solid support or a cocatalyst-modified support with a metal complex through a covalent bond, hydrogen bond, or coordination bond (Scheme A, left); (b) generation of ion pairs by mixing the solid support/cocatalyst with a transition-metal precatalyst (Scheme A, right). ,,− ,− Recently, Chen and co-workers reported an ionic cluster strategy that can enable product morphology control utilizing metal salt polar α-polar monomers (Scheme B) . However, the use of inorganic supports and metal salt-type polar monomers results in the polyolefin material containing insoluble inorganic impurities, which may compromise the polymer performance in food, biomedical, or microelectronic applications. , Alternatively, polymer supports such as polystyrene (PS)-based resin and latex particles can be used as organic supports so that the obtained polyolefin does not contain insoluble inorganic solids. , Nevertheless, few studies have focused on the appl...…”