A Single-Crystal Model for MgCl₂–Electron Donor Support Materials: [Mg₃Cl₅(THF)₄Bu]₂ (Bu = n-Butyl)

Abstract

The influence of the electron donor tetrahydrofuran (THF) on the formation of the crystalline morphology of MgCl 2 was studied. MgCl 2 was synthesized from magnesium and 1-chlorobutane in the presence of THF with the THF/Mg molar ratio ranging from 0.063 to 2.0. With the highest amounts of THF crystalline particles were formed, as evidenced from scanning electron microscopy images. The X-ray structure analysis of these single crystals revealed the new organometallic Mg compound [Mg 3 Cl 5 (THF) 4 Bu] 2 (Bu = n-butyl), which has an open dicubanelike structure with four octahedrally and two tetrahedrally coordinated Mg atoms. The compound also contains two butyl groups directly bound to the Mg atoms at the opposite corners of the dicubane structure. With the lowest THF amounts, structurally disordered MgCl 2 /THF complexes were formed. The transition from single crystals toward particles with an amorphous morphology appeared to occur through an intermediate type of morphology with a three-dimensional network structure. The network structure is formed from a thin (30−100 nm) fiberlike MgCl 2 /THF material. Infrared and solid-state 13 C nuclear magnetic resonance spectroscopy measurements revealed different types of Mg sites present in the MgCl 2 /THF complexes.

Activation and In Situ Ethylene Polymerization on Silica-Supported Ziegler–Natta Catalysts

“…5,7,8,[29][30][31] In our previous works we have demonstrated the potential of a multi-technique approach in unraveling the nature of the active TiCl x phase in catalysts obtained by reacting together titanium and magnesium chloride tetrahydrofuranate precursors and the aluminum-alkyl activator. 7,8 The investigation is more complex when the TiCl x and MgCl x phases are simultaneously supported on dehydroxylated silica in presence of tetrahydrofuran.…”

Ziegler–Natta catalysts supported on crystalline and amorphous MgCl2/THF complexes

“…The support was synthesized as described previously in the literature [27]. Autoclave was packed with Mg (0.5 g, 0.021 mol), few small crystals of iodine, octane (20 mL), 1-chlorobutane (4.6 mL, 0.044 mol), and THF (0.005 or 0.041 mol).…”

“…In our previous study [27], the effect of THF on the morphology and the structure of synthesized MgCl 2 were studied. It was found that a transition from a fully crystalline to structurally disordered complexes can be controlled by adjusting the amount of THF in the autoclave synthesis of MgCl 2 .…”

A Comparative Study of AlCl3and FeCl2-Modified TiCl4/MgCl2/THF Catalytic System in the Presence of Hydrogen for Ethylene Polymerization

“…This is due to its easiness to prepare, which leads to the lower in cost. It also provides good hydrogen response and the moderate activity and increases the molecular weight of polymer [4][5][6]. Besides, Sobota [7] revealed that THF is the most mature as a selectivity control agent in ethylene polymerization.…”