Alkylaluminum Chlorides Research Articles

First example of cationic titanium (III) complexes with crown ether as catalysts for ethylene polymerization

Complex cations with a vacant coordination site are considered as the most plausible catalytically active centers of metallocene and post-metallocene polymerization catalysts. For the first time we demonstrated that cationic titanium (III) complexes stabilized with crown ether can be used as pre-catalysts for ethylene polymerization. In the presence of alkyl aluminum chlorides and MgBu2 as cocatalysts, these complexes catalyze ethylene polymerization to produce Ultra High Molecular Weight Polyethylene (UHMWPE) with productivity up to 4650 kgPE/mol Ti h⋅atm and molecular weight up to 1.8·106 Da. UHMWPE powders were processed by the solid-phase method with subsequent orientation drawing into high-strength (1.4–2.1 GPa) and high-modulus (91–118 GPa) films.

Effect of alkylaluminum structure and aggregation state on the micro-kinetics of ethylene polymerization catalyzed by α-diimine nickel complex

2-thiophenecarbonyl chloride (TPCC) quenching method was used into the study of alkylaluminum activation behavior on α-diimine nickel catalysts. The influence of alkylaluminum structure (AlEt2Cl, Al2Et3Cl3, AlEtCl2 and modified methylaluminoxane (MMAO)) and polymerization temperature on the kinetic factors (active center concentration [C*] and chain propagation rate constant kp) of ethylene polymerization catalyzed by the system was systematically studied. It was found that, compared with MMAO, alkyl aluminum chloride could better activate catalyst and produced more active centers in the polymerization system, but the value of kp was lower than MMAO. Unexpectedly, as the polymerization temperature increased, [C*] in the polymerization system with AlEtCl2 as cocatalyst gradually increased, and kp decreased. But the change of [C*] and kp of the polymerization system with MMAO as cocatalyst was opposite. It was proposed that cocatalyst is one of the factors affecting the thermal stability of catalyst.

Cationic polymerization of β-pinene in the presence of alkylaluminum chlorides as catalysts

Cationic polymerization of β-pinene, a naturally occurring monomer, was studied in the presence of different alkylaluminum chlorides ((iBu)3Al2Cl3, Et3Al2Cl3 и Мe2AlCl) in the solvent mixture dichloromethane/methylcyclohexane (DCM/MCH) at –78 °C. The effect of catalyst concentration [(iBu)3Al2Cl3] and various electron donors on the polymerization rat and molecular-weight characteristics of synthesized poly(β-pinenes) was investigated. Controlled cationic polymerization of β-pinene was carried out in the presence СumCl/Мe2AlCl initiating system. The polymers with controlled molecular weight up to 6400 g/mol and relatively low polydispersity (Mw/Mn < 1.42) were synthesized. Microstructure of synthesized poly(β-pinene) was investigated by 1H NMR spectroscopy.

MAO‐free copolymerization of ethylene and 1-hexene with Ti (IV) complexes supported by fluorinated 2-hydroxymethylphenol derivatives

Ethylene/1-hexene copolymerization was carried out with a new Ti (IV) complexes stabilized by fluorinated 2-hydroxymethylphenol derivatives and activated by MAO-free binary cocatalysts—{alkyl aluminum chloride + Bu2Mg}. Structures and properties of the obtained copolymers were measured by DSC, GPC and 13C NMR. The effects of the ligand structure and the nature of organoaluminum activator on the polymer yield, comonomer incorporation, polymer composition, molecular weight, polydispersity index and stress–strain behavior have been investigated. The results indicated that the complex with adamantyl substituent was the most active in this series. The obtained copolymer exhibited the highest 1-hexene incorporation content of 18.9 mol%

Olefin polymerization behavior of titanium(IV) alkoxo complexes with fluorinated diolate ligands: The impact of the chelate ring size and the nature of organoaluminum compounds

Titanium(IV) coordination compounds are effectively used as precatalysts for ethylene polymerization and copolymerization with other olefins. New titanium(IV) complexes 3b–d with ligands containing two diphenylcarbinol fragments linked by the perfluorinated hydrocarbon units –CF2– or –C2F4– were synthesized. The structures of complexes 3b and 3d were determined by X‐ray diffraction. Titanium atoms in 3b have a distorted trigonal‐bipyramidal coordination environment while spiro‐complex 3d is characterized by tetrahedral molecular geometry. The catalytic behavior of complexes activated by mixtures of Bu2Mg and alkylaluminium chlorides from among Me2AlCl, Et2AlCl, EtAlCl2, and Et3Al2Cl3 were studied. The resulting catalytic systems catalyze ethylene polymerization to afford ultra‐high molecular weight polyethylene, suitable for modern processing methods, and the solvent‐free solid state formation of super high‐strength (1.37–2.75 GPa) and high‐modulus (up to 138 GPa) oriented film tapes. The same catalytic systems catalyze ethylene copolymerization with 1‐hexene to afford high molecular weight semicrystalline elastomeric polymers containing up to 20% of comonomer units.

Effect of Ancillary Ligands as a Part of Counteranion in Neodymium-Catalyzed Isoprene Polymerization

Organic halides and alkylaluminum chlorides are known as representative additives of lanthanide catalyst systems for the polymerization of conjugated dienes, which enhance the activity and stereosp...

Preparation of Lubricant Base Stocks with High Viscosity Index through 1-Decene Oligomerization Catalyzed by Alkylaluminum Chloride Promoted by Metal Chloride

In this paper, poly-α-olefins oil base stocks with medium kinematic viscosity and high viscosity index were prepared by 1-decene oligomerization catalyzed using the alkylaluminum chloride catalyst ...

Novel alkoxo-titanium(IV) complexes with fluorinated 2-hydroxymethylphenol derivatives as catalysts for the formation of ultra-high molecular weight polyethylene nascent reactor powders

A series of titanium (IV) complexes 3a–g stabilized by fluorinated derivatives of 2-hydroxymethylphenol have been synthesized; their composition and structure have been confirmed by NMR, IR-spectroscopy and elemental analysis. The structures of compounds 3c, 3f and 3g have been unambiguously established by X-ray diffraction study. The complexes in the presence of a binary cocatalysts {alkyl aluminum chloride + MgBu2} catalyze ethylene polymerization to afford Ultra High Molecular Weight Polyethylene (UHMWPE). The effects of substituents in the ligands on the catalytic activity and properties of the obtained polymer – molecular weight, DSC melting behavior, and morphology of nascent reactor powders have been investigated. UHMWPE samples were processed by a solid-state uniaxial deformation into high-strength (up to 2.65 GPa) and high-modulus (over 140 GPa) oriented film tapes, which indirectly indicates a low degree of entanglements between the macromolecular chains.

Oligomerization of ethylene in the presence of heterogenized complex catalytic systems based on ionic liquid‐type substituted zirconium phenolates

The oligomerization of ethylene was investigated in the presence of novel catalytic systems consisting of alkylaluminium chlorides and heterogenized zirconium phenolates containing amino and imino hydrochloride substituents. It was determined that the composition of a synthesized oligomer and the activity or selectivity of the catalyst systems depend on various parameters such as the molar ratio of Zr:Al, the composition of alkylaluminium, the temperature of the reaction, the pressure of ethylene and the structure of zirconium phenolates. The results showed that C4‐C10 linear α‐olefins were obtained with high selectivity when diethylaluminium chloride was used as a co‐catalyst. The process of the separation of a synthesized oligomer from the catalyst containing amino and imino hydrochloride ionic liquid substituents was carried out by simple decantation, and after this process zirconium complexes could be reused several times for successive ethylene oligomerizations.

ChemInform Abstract: Alkylaluminum Chloride Catalyzed Ene Reactions of Formaldehyde with Unsaturated Carboxylic Acids, Esters, and Alcohols.

Dimethylaluminum chloride and ethylaluminum sesquichloride catalyze the ene reactions of formaldehyde with the C,C-double bond of unsaturated carboxylic acids, for example oleic acid and 10-undecenoic acid, and of the respective alcohols. Ethylaluminum dichloride catalyzes the ene reactions of formaldehyde with the respective carboxylic acid esters

DRIFTS study of the interaction of the internal donor in TiCl 4/di-n-butyl phthalate/MgCl 2 catalysts with AlEt 3 cocatalyst

The interaction of di-n-butyl phthalate (DBP as the internal donor) with AlEt 3 cocatalyst was studied by DRIFT spectroscopy for the DBP/MgCl 2 sample and supported TiCl 4/DBP/MgCl 2 catalysts. For DBP/MgCl 2 sample, it was shown that AlEt 3 partially removes all types of DBP complexes from the MgCl 2 surface and adsorbs on surface sites released by the removal of DBP. In the case of supported catalysts, the cocatalyst predominantly removes more weak DBP complexes. In addition, the cocatalyst completely removes loosely coordinated DBP and surface complexes of phthaloyl chlorides formed at the catalyst preparation. A part of removed DBP can adsorb again on the catalyst surface as complexes with surface alkylaluminum chloride compounds. The external donor alkylalkoxysilane does not markedly influence the removal of DBP complexes from the catalyst surface.

Synthesis, Characterization, and Catalysis in ϵ-Caprolactone Polymerization of Aluminum and Zinc Complexes Supported by N,N,N-Chelate Ligands

A series of aluminum and zinc complexes supported by pyridine-based N,N,N-chelate ligands have been synthesized and characterized. Treatment of 2-(3,5-dimethyl-1H-pyrazol-1-yl)-6-((trimethylsilyl)methyl)pyridine (2) with LiBun/tmeda and then PhCN afforded a lithium complex [Li{2-(3,5-Me2C3HN2)-6-{N(SiMe3)C(Ph)═CH}C5H3N}] ([LiL]) (3). Reaction of 3 with ZnCl2 formed corresponding zinc chloride complex [Zn(Cl)L] (4), which was transformed to methyl- or ethylzinc complex [Zn(R)L] (R = Me, 5a; R = Et, 5b) by treatment with methyl- or ethyllithium. The ethylzinc complex (5b) was also generated by reaction of 4 with LiHBEt3. Reaction of 4 with AlR3 (R = Me, Et) gave alkyl aluminum chloride complexes [Al(Cl)(R)L] (R = Me, 6a; R = Et, 6b). Structurally similar N,N,N-chelate zinc complex [Zn(Et){2-(3,5-Me2C3HN2)-6-{N(Ph)P(Ph2)═CH}C5H3N}] (9) was obtained by reaction of 2-(3,5-Me2C3HN2)-6-{PhN═P(Ph)2CH2}C5H3N (8) with ZnEt2. The aluminum and zinc complexes bearing [{2-{N(SiMe3)═P(Ph)2}-6-{N(SiMe3)P(Ph)2═CH}C5H3N}]− ligand, 14 and 15, were similarly prepared by reaction of 2-{Me3SiN═P(Ph)2}-6-{Me3SiN═P(Ph)2CH2}C5H3N with AlEt3 and ZnEt2, respectively. The new compounds were characterized by NMR spectroscopy and elemental analyses. The molecular structures of complexes 5a, 9, 14, and 15 were determined by single-crystal X-ray diffraction techniques. The catalysis of complexes 5a, 6a, 14, and 15 in the ring-opening polymerization of ϵ-caprolactone was evaluated.

The multiple-site nature of ethylene polymerization catalysts based on zirconyl carboxylates

Zirconyl carboxylates in combination with alkylaluminum chlorides were shown to be active catalysts for the reaction of ethylene polymerization. It was found that the molecular-mass distribution of ethylene oligomers depends considerably on the donor-acceptor properties of a modifier of the catalytic system. The optimal conditions for obtaining the C4–C8 and C8–C18 fractions of linear α-olefins with yields of 75–80%, respectively, were determined. Experimentally observed deviation of the composition of oligomerization products from the statistical distribution of the Schulz-Flory type is caused by the multistie character of the catalytic system used. Modifiers that provide the formation of catalytic centers with higher coordination unsaturation (type I) promote the selective formation of the C4–C8 fraction (95%). Modifiers capable of forming semilabile ligands (type II) lead to an increase in the yield of the middle, C6–C10 and C8–C18 fractions. Modifiers with stronger chelating properties (type III) direct the process toward the formation of macromonomers and polymers of ethylene.

Improving Stability of FCC Gasoline Using Ionic Liquids Catalyst After Treating

The ionic liquids used herein were alkyl-containing ammonium-aluminum chloride ionic liquids system, which were made by the reaction of short-chain alkyl ammonium salts and aluminum chloride. The factors influencing stability of gasoline and the importance of improving it were described in this article, so was the characteristic of ionic liquids. A novel way to improve the stability of gasoline using ionic liquids was studied herein, as well as the study of decreasing the basic nitrogen content and the sulfur content of mercaptan, treating the gasoline and decreasing the olefin content of gasoline with supported ionic liquids catalyst on a small scale. After treating, the sulfur content of gasoline decreased to 0 nearly, and the basic nitrogen content decreased greatly too, whereas the octane number (RON) of gasoline increased a little. To improve the catalysis of ionic liquids and prolong the using life of ionic liquids, a buffering agent was added into ionic liquids. Ionic liquids catalyst, as a green catalyst friendly to environment, can displace many other alkylation catalysts, decrease the olefin content of gasoline, and show their notable advantages: mild conditions, short reaction time, simple operation, easy separation of the products and the catalyst.

Microelectrode studies of reversible Mg deposition in THF solutions containing complexes of alkylaluminum chlorides and dialkylmagnesium

A kinetic study of Mg deposition on Pt surfaces has been performed using Pt microelectrodes. The solutions chosen included tetrahydrofuran (THF) and several types of Mg–Al–R–Cl complex electrolytes from which magnesium can be deposited reversibly. The complexes included an all-inorganic, Cl-containing MgCl 2:AlCl 3 (1:1) complex compound, all-organic Bu 2Mg with different ratios of Bu 2Mg, and various combinations of AlEtCl 2 and AlEt 3. Tafel slopes of the resulting polarization curves obtained both by CV and potential step techniques were carefully analyzed within the framework of a complicated, three-stage electrocrystallization mechanism related to four consecutive and two parallel steps in the first stage (ad-atom formation on the metallic interface) followed by surface diffusion and embedding of Mg-ad-atoms in the growth kink sites. This mechanism not only explains the peculiar kinetic data on Mg deposition from these complex solutions, but also provides a natural route for the comparison of a Mg deposition mechanism with that of gold and Ni depositions from cyanide and AlCl 3–BPC–NiCl 2 room temperature molten salts, respectively. We also discuss the uniqueness of these THF-based complex solutions for metallic Mg deposition, and compare the electrodeposition mechanism in this electrolyte with the electrochemistry of Mg in thionyl chloride solutions.

Synthesis of butyl rubber in hexane using a mixture of Et2AlCl and EtAlCl2 in the initiating system

AbstractA method was studied to obtain butyl rubber in hexane at −75 and −60°C using a mixture of a major amount of diethylaluminum chloride and a minor amount of ethylaluminum dichloride in the initiating system. The Jaacks method was used to determine the monomer reactivity ratio of isobutylene in copolymerization with isoprene in hexane at −75°C with the above initiating system; rIB = 1.54 ± 0.06. This value was different from a literature value rIB = 1.08 when just EtAlCl2 was used in hexane at −80°C. The mixture of both alkylaluminum chlorides in the initiating solution was subsequently directly activated with minute amounts of water or methylaluminoxane (MAO). The use of the modified initiators resulted in higher molecular weights, higher degrees of conversion, and higher isoprene contents in the butyl rubber. At the same time, temperature control was good during polymerizations. With modified alkylaluminum halides, the monomer reactivity ratio of isobutylene in copolymerization with isoprene in hexane at −75°C was close to unity, similar to the reported case with just EtAlCl2. The system activated with MAO made it possible to synthesize butyl rubber in hexane at −60°C having main characteristics typical of commercial butyl rubber manufactured in methyl chloride at −95°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2360–2364, 2003

One-step synthesis of trialkylaluminum derivatives and dialkylaluminum hydrides by the reaction of alkaline metal aluminum hydrides with α-olefins and alkylaluminum chlorides

A simple method for one-step preparation of the organoaluminum compounds R3Al, R2AlH, R2R"Al, and RR"AlH by the reaction of MAlH4 (M = Li, Na) with R2AlHal (Hal = Cl, Br) and α-olefins (3-methylbut-1-ene, hex-1-ene, oct-1-ene, dec-1-ene) was proposed.

Thermodynamics and Thermochemistry of Organoaluminum Compounds

The accuracy and reliability of thermodynamic data on vaporization of trialkylaluminum, alkylaluminum hydrides, and alkylaluminum chlorides and of thermochemical data for these compounds were estimated on the basis of author's and published data. A unified system of consistent thermodynamic characteristics of the organoaluminum compounds was proposed, and the enthalpies of vaporization of a number of unstudied compounds and the dissociation energies of Al-R bonds were estimated.

REACTIONS OF ALKYLALUMINIUM CHLORIDES WITH DIOLS. CRYSTAL STRUCTURE OF CI5AI3[OC(CH3)2CH2C(CH3)2O

Article REACTIONS OF ALKYLALUMINIUM CHLORIDES WITH DIOLS. CRYSTAL STRUCTURE OF CI5AI3[OC(CH3)2CH2C(CH3)2O]2 was published on March 1, 2000 in the journal Main Group Metal Chemistry (volume 23, issue 3).

Carbocationic polymerization of isobutylene with alkyl aluminum chloride / methyl acrylate as the initiating system

A solution of alkyl aluminum chloride mixed with methyl acrylate (MA) was prepared and used as the initiating system for the polymerization of isobutylene (IB) carried out in a mixed butane-butene fraction at -50°C. The polymers obtained at different mole ratios AlRmCl3-m to methyl acrylate ([A1]/[MA]) were characterized by gel permeation chromatography (GPC). The results show that the uncontrolled polymerization process occurring in the absence of MA can be effectively controlled in the presence of small amounts of MA and that it produces polyisobutylene of a narrow molecular weight distribution. The 1H-NMR spectrum of the low-molecular-weight polymer shows that MA acts mainly as an inert electron donor to mediate the polymerization and also partly as an initiator.