Modification of olefin polymerization catalysts. III. A sup 13 C CP-MAS NMR study of adsorption of silyl ethers on MgCl sub 2 -supported Ziegler-Natta catalysts

Journal Article · Thu Feb 01 00:00:00 EST 1990 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(90)90235-C· OSTI ID:6188734

Pakkanen, T T; Vaehaesarja, E; Pakkanen, T A ^[1]; Iiskola, E; Sormunen, P ^[2]

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1. Univ. of Joensuu (Finland)
2. Neste Chemicals, Kulloo (Finland)

A {sup 13}C CP-MAS NMR and elemental analysis study of adsorption and interaction of silyl ethers, RSi(OMe){sub 3} (R = Et, Ph, OMe), as internal and external electron donors with MgCl{sub 2}-supported Ziegler-Natta catalyst has been carried out. A chemical activation of anhydrous MgCl{sub 2} with EtOH and AlEt{sub 3} produces a high-surface-area support stabilized by an organoaluminum compound, AlEt{sub 2}(OEt). In a treatment of the aluminum-modified MgCl{sub 2} support with silyl ether, the aluminum surface complex is retained and silyl ether is almost totally incorporated into the support. {sup 13}C CP-MAS NMR data of the methoxy region indicate that a mobile liquid-like silyl ether species dominates, except in the case of Si(OMe){sub 4}, where a more strongly bound species is also present on the support. TiCl{sub 4} treatment removes the weakly adsorbed silyl ether species, leaving a species which is attributed to an aluminum-bound silyl ether surface complex. No evidence of titanium-bound silyl ether species was found in the solid state or in solution where TiCl{sub 4} undergoes with silyl ethers an exchange reaction forming a yellow solid identified as (TiCl{sub 2}(OMe){sub 2}){sub x}. Activation of the catalyst with AlEt{sub 3} at a high Al:Ti ratio produces a material with a low silyl ether coverage showing a weak methoxy signal in {sup 13}C CP-MAS. The linewidths of the observed signals in {sup 13}C CP-MAS NMR are in the range 5-10 ppm at every stage of preparation of the catalyst, indicating heterogeneity of the coordination sites on the surface of chemically activated MgCl{sub 2}.

• OSTI ID: 6188734
• Journal Information: Journal of Catalysis; (USA), Vol. 121:2; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
02 PETROLEUM
ALKENES
POLYMERIZATION
ETHERS
ADSORPTION
ZIEGLER CATALYST
SORPTIVE PROPERTIES
ALUMINIUM COMPOUNDS
CARBON 13
CATALYST SUPPORTS
CATALYTIC EFFECTS
CHEMICAL ACTIVATION
CHEMICAL PREPARATION
ELECTRON TRANSFER
ETHANOL
MAGNESIUM CHLORIDES
NUCLEAR MAGNETIC RESONANCE
ORGANOMETALLIC COMPOUNDS
SURFACE PROPERTIES
TITANIUM CHLORIDES
ALCOHOLS
ALKALINE EARTH METAL COMPOUNDS
CARBON ISOTOPES
CATALYSTS
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
EVEN-ODD NUCLEI
HALIDES
HALOGEN COMPOUNDS
HYDROCARBONS
HYDROXY COMPOUNDS
ISOTOPES
LIGHT NUCLEI
MAGNESIUM COMPOUNDS
MAGNETIC RESONANCE
NUCLEI
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
RESONANCE
SORPTION
STABLE ISOTOPES
SYNTHESIS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties
020400 - Petroleum- Processing