Wednesday, November 2, 2016

Single-Site Heterogeneous Catalysts for Olefin Polymerization Enabled by Cation Exchange in a Metal-Organic Framework



CATEGORY: METAL ORGANIC FRAMEWORKS
Single-Site Heterogeneous Catalysts
 for Olefin Polymerization Enabled by Cation Exchange in a Metal-Organic Framework
Type
Journal Article
Author
Robert J. Comito
Author
Keith J. Fritzsching
URL
Volume
138
Issue
32
Pages
10232-10237
Publication
Journal of the American Chemical Society
Date
August 17, 2016
Abstract
The manufacture of advanced polyolefins was enabled by the development of single-site heterogeneous catalysts. Metal-organic frameworks (MOFs) demonstrate great potential as heterogeneous catalysts that may be designed and tuned on the molecular level. Authors report exchange of zinc ions in Zn5Cl4(BTDD)3, H2BTDD = bis(1H-1,2,3-triazolo[4,5-b],[4′,5′-i])dibenzo[1,4]dioxin) (MFU-4l) with reactive metals serving to establish a general platform for selective olefin polymerization in a high surface area solid promising for industrial catalysis.
Characterization of polyethylene produced by these materials demonstrates both molecular and morphological control. Reactivity approaches single-site catalysis, as evidenced by low polydispersity indices, and good molecular weight control. Authors show that these new catalysts copolymerize ethylene and propylene. Uniform growth of the polymer around the catalyst particles provides a mechanism for controlling the polymer morphology, a relevant metric for continuous flow processes.

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