25-30 August 2019
Henry Ford Building
Europe/Berlin timezone

47,49Ti Solid State NMR and DFT Study of Ziegler-Natta Catalyst

Not scheduled
4h
Harnack House and Henry Ford Building

Harnack House and Henry Ford Building

Board: 193
Poster Posters

Speaker

Takahiro IIJIMA

Description

In Ti-based Ziegler-Natta catalysts (ZNCs), disagreements exist concerning which lateral surface of the MgCl$_2$ support adsorbs Ti species so as to be an active site for the catalysis of polymerization. In the present paper, we investigated the local structure of TiCl$_4$ adsorbed onto the surface of MgCl$_2$ by $^{47,49}$Ti solid-state nuclear magnetic resonance (NMR) spectra at 21.8 T along with density functional theory (DFT) calculations. The magic-angle-spinning NMR spectrum of the TiCl$_4$/MgCl$_2$ adduct sample prepared by 20 h of milling, which exhibited broadened and shifted peaks compared to that of the sample without milling, was simulated by a Czjzek model considering the distribution of quadrupole interaction parameters. The electric field gradient and chemical shielding tensors of $^{49}$Ti were obtained via DFT calculations for model molecules of TiCl$_4$, 2TiCl$_4$, and Ti$_2$Cl$_8$ adsorbed onto the (110), (104), and (104)-step defect surfaces of MgCl$_2$. By comparing the obtained NMR parameters, the $^{47,49}$Ti NMR spectrum of the milled sample was assigned to TiCl$_4$ adsorbed onto the (104) surface of MgCl$_2$, which may not be a principal component of adsorption.

Primary authors

Takahiro IIJIMA Dr Tadashi SHIMIZU (National Institute for Materials Science) Dr Atsushi GOTO (National Institute for Materials Science) Dr Kenzo DEGUCHI (National Institute for Materials Science) Dr Toshihito NAKAI (JEOL Resonance Corporation) Dr Ryutaro OHASHI (Kanazawa University) Dr Masayoshi SAITO (Toho Titanium Corporation)

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