Novel titanium(IV) complexes stabilized by 2-hydroxybenzyl alcohol derivatives as catalysts for UHMWPE production

Тuskaev, Vladislav А.; Гагиева, С. Ч.; Kurmaev, Dmitrii A.; Zubkevich, Sergey V.; Kolosov, Nikolay A.; Golubev, Evgenii K.; Никифорова, Г. Г.; Khrustalev, Victor N.; Булычев, Б. М.

doi:10.1016/j.jorganchem.2017.12.027

Cited by 16 publications

(7 citation statements)

References 23 publications

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“…The resulting polymer should be suitable for uniaxial and biaxial solid-state processing and is expected to match the mechanical properties of the homogeneous catalysis counterpart. Although the synthesis of UHMWPE using a heterogeneous catalytic system is not new, ,− the low entangled state that can lead to properties equivalent to those of the homogeneous catalytic system has not been reported yet. Below, experimental findings for the synthesis of UHMWPE using heterogeneous catalytic systems are recalled.…”

Section: Introductionmentioning

confidence: 99%

Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

et al. 2022

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Several homogeneous postmetallocene complexes are known to produce weakly entangled ultrahigh-molecular-weight polyethylene (disentangled UHMWPE) under controlled polymerization conditions leading to ultimate mechanical properties. Major challenges in using a homogeneous catalyst system exist such as reactor fouling and uncontrolled polymer morphology, which could be addressed by heterogenization of the single-site complex. In such a scenario, a heterogeneous catalytic system that can synthesize ultrahigh-molecular-weight polyethylene with a reduced number of entanglements, to an extent that the mechanical properties are equivalent to those obtained using a postmetallocene catalyst in a homogeneous condition, remains a challenge. Herein, a magnesium chloride based in situ formed activator/support, MgCl x /Et n Al y (2-ethyl-1-hexoxide) z , is employed with a highly active bis[N-(3-tert-butylsalicylidene)pentafluoroanilinato] titanium(IV) dichloride (Cat. 1) for the synthesis of ultrahigh-molecular-weight polyethylene with a reduced number of entanglements. A novel route is adopted to make a nano-support that allows tailoring of the entangled state and control over the resultant morphology without reactor fouling and wall sheeting, thus providing the feasibility of pursuing the polymerization via a continuous process. The synthesized nascent polymer shows the formation of single crystals of linear UHMWPE, identifying the fold surface and crystal thickness and suggesting a low entangled state. The topological differences with the commercial entangled sample are identified by chain diffusion from the noncrystalline to crystalline region via solid-state NMR, following melting kinetics via DSC, and transformation of the nonequilibrium melt into the equilibrium state via rheology. Thus, the obtained disentangled crystals can be compressed in the solid state, without melting, to an extent that the macroscopic forces can be transferred to the molecular level. This allows the desired chain orientation for securing the ultimate tensile modulus (>200 N/tex) and tensile strength (>4.0 N/tex) in the synthesized low entangled linear polyethylene having a weight average molar mass exceeding a million grams per mole. These mechanical properties are equivalent to those perceived using a homogeneous catalytic system and are the first of their kind reported in a polymer synthesized using a heterogeneous catalytic system.

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Section: Introductionmentioning

confidence: 99%

Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

et al. 2022

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“…A search of the crystal structure literature reveals that there are only a handful of group 4 structurally characterized 2methoxide phenoxide derivatives available including [TiCl-(μ,κ 2 -L′)(κ 2 -H-L′•tol)] (where L′ = 2,4-di-tert-butyl-6-(oxidomethyl)phenolato), 35 4,6-bis(2-phenylpropan-2-yl)phenolato, 36 and [Ti 2 (μ 3 ,κ 2 -L″(μ 2 ,κ 2 -L″) 2 (OPr i ) 2 ] 2 (where L″ = 4-bromo-2-methoxy-6-(oxidomethyl)phenolato). 37 However, these were produced through the reaction of the 2hydroxybenzyl alcohol reaction with TiCl 4 or [Ti(OPr i ) 4 ], not the reduction of the aldehyde, as noted for 1a−6b. The remainder of these family members are derivatives that are cocrystallized with a Rh metal center present: [(η 5 -C 5 Me 5 )Ti-(OC 6 H 3 -(OCH 2 )) 2 {Rh(cod)} 2 ]SO 3 CF 3 , 38 [(η 5 -C 5 Me 5 )Ti-(OC 6 H 3 -(OCH 2 )) 2 Rh(cod)], 39 and [(η 5 -C 5 Me 5 )Ti(OC 6 H 3 -(OCH 2 )) 2 Rh(CO) 2 ] 39 (where cod = cyclooctadiene).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…A search of the crystal structure literature reveals that there are only a handful of group 4 structurally characterized 2-methoxide phenoxide derivatives available including [TiCl(μ,κ 2 -L′)(κ 2 -H-L′·tol)] (where L′ = 2,4-di- tert -butyl-6-(oxidomethyl)phenolato), 4,6-bis(2-phenylpropan-2-yl)phenolato, and [Ti 2 (μ 3 ,κ 2 -L″(μ 2 ,κ 2 -L″) 2 (OPr i ) 2 ] 2 (where L″ = 4-bromo-2-methoxy-6-(oxidomethyl)phenolato) . However, these were produced through the reaction of the 2-hydroxybenzyl alcohol reaction with TiCl 4 or [Ti(OPr i ) 4 ], not the reduction of the aldehyde, as noted for 1a – 6b .…”

Section: Resultsmentioning

confidence: 99%

Trapped Intermediate of a Meerwein–Pondorf–Verley Reduction of Hydroxy Benzaldehyde to a Dialkoxide by Titanium Alkoxides

et al. 2019

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A series of titanium alkoxides ([Ti(OR) 4 ] (OR = OCH(CH 3 ) 2 (OPr i ), OC(CH 3 ) 3 (OBu t ), and OCH 2 C(CH 3 ) 3 (ONep)) were modified with a set of substituted hydroxyl-benzaldehydes [HO-BzA-L x : x = 1, 2-hydroxybenzaldehyde (L = H), 2-hydroxy-3-methoxybenzaldehyde (OMe-3), 5-bromo-2-hydroxybenzaldehyde (Br-5), 2-hydroxy-5-nitrobenzaldehyde (NO 2 -5); x = 2, 3,5-di-tert-butyl-2-hydroxybenzaldehyde (Bu t -3,5), 2-hydroxy-3,5-diiodobenzaldehyde (I-3,5)] in pyridine (py). Instead of the expected simple substitution, each of the HO-BzA-L x modifiers were reduced to their respective diol [(py , NO 2 -5 (4a•4py); x = 2, Bu t -3,5 (5a), I-3,5 (6a), ONep; x = 1, L = H (1b), OMe-3 (2b), Br-5 (3b•py), NO 2 -5 (4b); x = 2, Bu t -3,5 (5b), I-3,5 (6b•py)), as identified by single crystal X-ray studies. The 1 H NMR spectral data were complex at room temperature but simplified at high temperatures (70 °C). Diffusion ordered spectroscopy (DOSY) NMR experiments indicated that 2a maintained the dinuclear structure in a solution independent of the temperature, whereas 2b appears to be monomeric over the same temperature range. On the basis of additional NMR studies, the mechanism of the reduction of the HO-BzA-L x to the dioxide ligand was thought to occur by a Meerwein−Pondorf−Verley (MPV) mechanism. The structures of 1a−6b appear to be the intermediate dioxide products of the MPV reduction, which became "trapped" by the Lewis basic solvate.

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“…Moreover, the values of tensile strength and average tensile modulus recorded at complex 4 are the highest in the entire series of titanium complexes stabilized by 2‐hydroxymethylphenol derivatives. [ 16,28–31 ] It is possible that the lower catalytic activity of binuclear complex 4 facilitates the formation of disentangled UHMWPE.…”

Section: Resultsmentioning

confidence: 99%

Binuclear Ti(IV) complex with new compartmental ligand 2,6‐(bis‐CF₃‐carbinol)‐4‐tert‐butylphenol as precatalysts for ethylene polymerization and its copolymerization with propylene and 5‐ethylidene‐norbornene

Тuskaev

Гагиева

Bogdanov

et al. 2021

Applied Organom Chemis

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The coordination chemistry of a new compartmental ligand 2,6‐(bis‐CF3‐carbinol)‐4‐tert‐butylphenol with Ti(IV) and Zr(IV) has been studied. The structures of Al, Ti, and Zr complexes with the participation of this ligand were established by X‐ray diffraction. Upon activation with Et2AlCl or Et3Al2Cl3 and Bu2Mg, Ti(IV) complex exhibited moderate catalytic activity for ethylene polymerization. The obtained UHMWPE samples were processed into high‐strength (up to 2.7 GPa) and high‐modulus (up to 162 GPa) films through solid‐phase molding and orientation drawing. The mononuclear and binuclear Ti(IV) complexes catalyzed the ternary copolymerization of ethylene, propylene, and 5‐ethylidene‐norbornene. Tercopolymers with a content of propylene units up to 36 mol% and 5‐EBN up to 8.6 mol% were synthesized with a high activity (2.8–6.3 tons of copolymer/mol Ti h); the mechanical characteristics of elastomeric materials have been studied.

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Novel titanium(IV) complexes stabilized by 2-hydroxybenzyl alcohol derivatives as catalysts for UHMWPE production

Cited by 16 publications

References 23 publications

Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

Trapped Intermediate of a Meerwein–Pondorf–Verley Reduction of Hydroxy Benzaldehyde to a Dialkoxide by Titanium Alkoxides

Binuclear Ti(IV) complex with new compartmental ligand 2,6‐(bis‐CF₃‐carbinol)‐4‐tert‐butylphenol as precatalysts for ethylene polymerization and its copolymerization with propylene and 5‐ethylidene‐norbornene

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Novel titanium(IV) complexes stabilized by 2-hydroxybenzyl alcohol derivatives as catalysts for UHMWPE production

Cited by 16 publications

References 23 publications

Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

Unprecedented Mechanical Properties in Linear UHMWPE Using a Heterogeneous Catalytic System

Trapped Intermediate of a Meerwein–Pondorf–Verley Reduction of Hydroxy Benzaldehyde to a Dialkoxide by Titanium Alkoxides

Binuclear Ti(IV) complex with new compartmental ligand 2,6‐(bis‐CF3‐carbinol)‐4‐tert‐butylphenol as precatalysts for ethylene polymerization and its copolymerization with propylene and 5‐ethylidene‐norbornene

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Binuclear Ti(IV) complex with new compartmental ligand 2,6‐(bis‐CF₃‐carbinol)‐4‐tert‐butylphenol as precatalysts for ethylene polymerization and its copolymerization with propylene and 5‐ethylidene‐norbornene