1080669-07-3Relevant academic research and scientific papers
New bis(aryloxy)-Ti(iv) complexes and their use for the selective dimerization of ethylene to 1-butene
Grasset, Fabien,Cazaux, Jean-Benoit,Magna, Lionel,Oliver-Bourbigou, Helene,Braunstein, Pierre
, p. 10396 - 10404,9 (2020/08/31)
New titanium complexes of general formula [(ArO)nTi(Oi-Pr) (4-n)] were synthesized and used as pre-catalysts for the selective dimerization of ethylene to 1-butene. The complexes were prepared in cyclohexane using [Ti(Oi-Pr)4] and one or two equivalents of the corresponding phenols (ArOH) at room temperature. In this work, both monodentate and chelating phenols were evaluated. For alkyl-substituted phenols, it was demonstrated that large steric hindrance at both ortho and ortho′ positions selectively yielded the mono-substituted complexes [(ArO)Ti(Oi-Pr)3]. Substitution at only one of the ortho positions allowed both the mono- and the di-substituted Ti complexes to be isolated. When a heteroatom was introduced on the phenol backbone, di-substitution systematically occurred except with phenols presenting a hemilabile -CH2NR2 group at the ortho position. Upon activation with 3 equiv. of AlEt3 at 20 bar and 60 °C, all the complexes selectively dimerized ethylene to 1-butene (>86% of butenes among which 99% of 1-butene). An increase of the steric bulk at the ortho position of the ligand or the introduction of a functional group led to decreased activity compared to [Ti(Oi-Pr)4].
PROCESS FOR OLIGOMERIZATION OF OLEFINS THAT USES A CATALYTIC COMPOSITION THAT COMPRISES AN ORGANOMETALLIC COMPLEX THAT CONTAINS A PHENOXY LIGAND THAT IS FUNCTIONALIZED BY A HETEROATOM
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Page/Page column 7-8, (2011/09/20)
The invention describes a process for oligomerization of the olefins into compounds or into a mixture of compounds of general formula CpH2p with 4≦p≦80 that implements a catalytic composition that comprises at least one organometallic complex of an element of group IV that is selected from among titanium, zirconium, or hafnium, whereby said organometallic complex contains at least one aryloxy-type (or phenyloxy-type) ligand that is functionalized by a heteroatom that is selected from among nitrogen, oxygen, phosphorus or sulfur or by an aromatic group.
Mono(aryloxido)titanium(IV) Complexes and their application in the selective dimerization of ethylene
Cazaux, Jean-Benoit,Braunstein, Pierre,Magna, Lionel,Saussine, Lucien,Olivier-Bourbigou, Helene
, p. 2942 - 2950 (2011/05/13)
We report on the synthesis of mono(aryloxido)titanium(IV) complexes of general formula [Ti[O(o-R)Ar]X3), with X = OiPr, ArO = 2-ie.rr-but:yl-4-methylphenoxy and. R = CMe3 (2a), CMe2Ph (2b) and CH2NMe2 (2c). Attempts to reach pure mono(aryloxido) complexes when R = CH2NMe(CH2Ph) (2d) or CH2N(CH2Ph)2 (2e) were unsuccessful, When R = CH2OMe, the analogous mononuclear complex was not obtained, and instead, a dinuclear complex [(2-ieri-butyl-4methyl-6- methoxymethylphenoxy) TiCl(OiPr)(H2-OiPr)2TiCl(OiPr) 2] (3) was formed. Complexes 2b and 3 were characterized by single-crystal X-ray diffraction, The former contains a tetrahedrally coordinated. TiIV centre, whereas in the latter the aryloxido ligand behaves as a chelating-bridging ligand between the two, chemically very different metal centres that form two face-sharing octahedra, Different synthetic approaches starting from. [Ti(OiPr)4] or [TiCl(OiPr) 3] were evaluated and are discussed, The hemllabile behaviour of the aryloxido ligand. resulting from, reversible coordination of its side arm was studied by variable-temperature 1H NMR spectroscopy for 2c (R = CH 2NMe2). Complexes 2a-d were contacted, with ethylene and AlEt3 as cocatalyst, When activated with AlEt3 (3 equiv.) at 20 bar and 60 ° C, complex 2c exhibits interesting activity (2100 g/gTi/h) for the selective dimerization of ethylene to 1-butene (92% C 4"=; 99+% C4=1), Noticeable differences in catalyst activity were observed when the R group was modified,
