FTIR study of the active ethene polymerisation catalyst, alumina-supported C6H6Cr(CO)3
1996; Royal Society of Chemistry; Volume: 92; Issue: 23 Linguagem: Inglês
10.1039/ft9969204763
ISSN1364-5455
AutoresGeoffrey Hunter, Colin H. Rochester, Anthony J. Wilkinson, J. D. Paton,
Tópico(s)Carbon dioxide utilization in catalysis
ResumoIR spectra are reported for C6H6Cr(CO)3 adsorbed on alumina which had been pretreated in vacuum at 500, 700 and 800 °C. Two dominant modes of adsorption involved H-bonding of surface hydroxy groups to benzene nuclei and O-ligation of CO groups to Lewis acidic Al3+ surface sites. Displacement of both benzene and CO ligands occurred and led to adsorbed subcarbonyl species. Ligand loss was enhanced by evacuation at 25 °C, mild heating or contact with ethene. Sub-carbonyl surface species contained coordinatively unsaturated Cr sites which were active for the polymerisation of ethene to give highly linear polyethene.
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