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High resolution transmission electron microscope observation of industrial high performance Ziegler catalysts
Author(s) -
Mori Hideharu,
Higuchi Tomohiro,
Otsuka Nobuo,
Terano Minoru
Publication year - 2000
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20001201)201:18<2789::aid-macp2789>3.0.co;2-i
Subject(s) - catalysis , transmission electron microscopy , high resolution transmission electron microscopy , zone axis , crystallography , cleavage (geology) , grinding , chemistry , materials science , electron microscope , specific surface area , chemical engineering , mineralogy , composite material , nanotechnology , optics , electron diffraction , diffraction , organic chemistry , physics , engineering , fracture (geology)
High resolution transmission electron microscopy (HRTEM) was used to directly observe the distribution of crystalline regions in Ziegler catalysts prepared by mechanical plus chemical routes (internal donor; Cat‐A: ethylbenzoate, Cat‐B: dibutylphthalate, Cat‐C: none) and by an entirely chemical route (internal donor; Cat‐D: dibutylphthalate). A comparison of Cat‐A, Cat‐B, and their precursors (ground products of an original MgCl 2 with a donor) indicates that MgCl 2 crystals are significantly destroyed by the co‐grinding procedure regardless of the kinds of internal donor, and further destruction preferentially occurs in Cat‐B compared with that in Cat‐A. The crystalline lattice of the original MgCl 2 is destroyed from the surface into the interior region in the catalysts prepared by the former method. The destruction of the crystals is found to be severe in the following order: Cat‐C ≥ Cat‐B > Cat‐A in the surface area, Cat‐C > Cat‐B > Cat‐A in the central area. On the other hand, Cat‐D shows the different distribution of crystalline regions, which are predominantly present in the near‐surface area, but absent in the central area. These results suggest that the distribution of MgCl 2 crystalline regions exhibit a strong correlation with the catalyst preparation procedures and, hence, the catalyst performance.