The structural and electronic properties of silica-supported titanium chloride tetrahydrofuranates samples, obtained by impregnating a polymer-grade dehydroxylated silica with TiCl4(thf )2 and TiCl3(thf )3 complexes, precursors of Ziegler–Natta catalysts, are investigated by means of FT-IR, XAS, XES and diffuse reflectance UV-Vis spectroscopy, coupled with DFT calculations. The properties of the two silica-supported samples are very similar, irrespective of the starting precursor. In both cases, most of the chlorine ligands originally surrounding the Ti sites are substituted by oxygen ligands upon grafting on silica. As a consequence, the electronic properties of silica-supported Ti sites are largely different from those of the corresponding precursors, and in both cases most of the grafted Ti sites have a formal oxidation state of +4. The whole set of experimental data provide evidence that mono-nuclear Ti species are mainly present at the silica surface.

Silica-supported Ti chloride tetrahydrofuranates, precursors of Ziegler–Natta catalysts

SEENIVASAN, Kalaivani;Gallo, Erik;VITILLO, Jenny Grazia;BORDIGA, Silvia;LAMBERTI, Carlo;GROPPO, Elena Clara
2013

Abstract

The structural and electronic properties of silica-supported titanium chloride tetrahydrofuranates samples, obtained by impregnating a polymer-grade dehydroxylated silica with TiCl4(thf )2 and TiCl3(thf )3 complexes, precursors of Ziegler–Natta catalysts, are investigated by means of FT-IR, XAS, XES and diffuse reflectance UV-Vis spectroscopy, coupled with DFT calculations. The properties of the two silica-supported samples are very similar, irrespective of the starting precursor. In both cases, most of the chlorine ligands originally surrounding the Ti sites are substituted by oxygen ligands upon grafting on silica. As a consequence, the electronic properties of silica-supported Ti sites are largely different from those of the corresponding precursors, and in both cases most of the grafted Ti sites have a formal oxidation state of +4. The whole set of experimental data provide evidence that mono-nuclear Ti species are mainly present at the silica surface.
DALTON TRANSACTIONS
42
35
12706
12713
http://pubs.rsc.org/en/content/articlelanding/2013/dt/c3dt50603g#!divAbstract
Ziegler–Natta catalysts; titanium chloride tetrahydrofuranates; FTIR spectyroscopy; XANES; EXAFS; XES; X-ray emission spectroscopy; DFT calculations; silica
Kalaivani Seenivasan;Erik Gallo;Andrea Piovano;Jenny G. Vitillo;Anna Sommazzi;Silvia Bordiga;Carlo Lamberti;Pieter Glatzel;Elena Groppo
File in questo prodotto:
File Dimensione Formato  
OpenSourceMS.pdf

embargo fino al 10/05/2014

Tipo di file: POSTPRINT (VERSIONE FINALE DELL’AUTORE)
Dimensione 636.79 kB
Formato Adobe PDF
636.79 kB Adobe PDF Visualizza/Apri
13_ZieglerNatta_XAS_XES.pdf

non disponibili

Tipo di file: PDF EDITORIALE
Dimensione 954.43 kB
Formato Adobe PDF
954.43 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2318/138532
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 27
  • ???jsp.display-item.citation.isi??? 22
social impact