TPD characterization of surface adsorption sites of model Ziegler–Natta polymerization catalysts

✍ Scribed by Seong Han Kim; Gabor A Somorjai

• Book ID: 104309159
• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 181 KB
• Volume: 161
• Category: Article
• ISSN: 0169-4332
• DOI: 10.1016/s0169-4332(00)00131-8

✦ Synopsis

The surface adsorption sites of titanium chloride films that can be used as model Ziegler-Natta polymerization catalysts Ž . have been investigated with temperature-programmed desorption TPD of various probe molecules. The adsorption sites can be differentiated depending on the heat of desorption of the molecule. Two titanium chloride films were produced by electron-induced chemical vapor deposition of TiCl and co-deposition of Mg and TiCl on gold substrates. The surfaces of 4 4

Ž . both films were chlorine-terminated. 1,3,5-Trimethylbenzene mesitylene was found to be an effective and non-destructive molecule for TPD characterization of adsorption sites on the model catalysts. The film produced by the electron-induced chemical vapor deposition had a distribution of adsorption sites that were not thermodynamically stable and subject to high-temperature annealing, while the film prepared by the co-deposition had a stable surface structure that was composed of Ž . domains of the MgCl 001 basal plane structure.