ISSN:
0941-1216
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
On Surface Compounds of Transition Metals. XL. Characterization of Chromium Doped Silica Catalyst Systems of the Phillips Type by Scanning Electron Microscopy with Energy Dispersive Analysing System (SEM/EDS)The surface of typical supports for the Phillips catalyst was studied by SEM. The seemingly smooth surfaces are composed by closely packed, ball-shaped substructures; macro- and micro-pores can be seen. Adherent particles on the surface (φ ≪ 1 μm) show the same substructures as the usual surface. After impregnation and activation/reduction of the catalysts crystallites are seen at the surface, which are characterized as Cr2O3 by their crystal shape and EDS analysis.Polymerization of ethylene occurs at the usually doped surface, while the Cr2O3 particles do not exhibit a special activity. Mechanically inforced breaks of the catalyst grains show the formation of threadlike polyethylene with diameters of 200 to 300 nm.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prac.199633801120
Permalink
