Mikhail A. Matsko

• Boreskov Institute of Catalysis

Using a new modification of a highly active vanadium-magnesium catalyst (VMC), data were obtained on the effect of hydrogen and hexene-1 content on the catalyst activity and the molecular structure of the resulting polymers. It was found that the formation of polyethylene (PE) with a wide bimodal molecular weight distribution (MWD) on VMC is associ...

The kinetics of copolymerization of ethylene with 1-hexene over highly active V-Mg Ziegler–Natta catalysts [VMC: VCl4/MgCl2 + Al (i-Bu)3] at different contents of vanadium (4 and 0.1 wt% of V) was studied. Data on copolymerization ability of these catalysts, molecular weight characteristics, and compositional homogeneity of the produced copolymers...

The paper describes ways for controlling the molecular structure of polyethylene (PE) produced over supported catalysts containing bis(imino)pyridyl complexes of Fe(II) (LFeCl2) and bis(imine) complexes of Ni(II) (*LFeCl2), which are anchored on silica gel modified by the introduction of alumina (SiO2(Al)). Under variation of polymerization conditi...

The article describes a method of the synthesis of carbon nanofibers (CNFs) and a technique for obtaining masterbatches, which are represented by CNFs with a layer of pre-synthesized polyethylene (PE) on their surface. Using scanning electron microscopy, it was shown that in-situ ethylene polymerization over the catalyst anchored on the CNF surface...

This paper presents data on the number of active centers (CPⁱ) with different stereospecificity and the values of propagation rate constant (kPⁱ) for these centers in the propylene polymerization over supported titanium-magnesium catalyst in the presence or absence of hydrogen. The indicated data were obtained by quenching the polymerization with r...

The data on the preparation of composite materials containing polyethylene and multi-walled carbon nanotubes (MWCNTs) of the Taunit brand are presented. To obtain these composites by in situ polymerization, a catalytic system formed by the interaction of an organomagnesium compound and TiCl4 on the surface of nanotubes was used. The catalyst fixed...

Data on the effect the concentrations of the monomer, triethylaluminium, and hydrogen on the molecular weight of polyhexene upon 1-hexene polymerization over supported titanium–magnesium catalyst are obtained. The ratios between propagation rate constant and the rate constants of the reactions of polymer chain transfer with monomer, triethylalumini...

The effect of a set of methoxy- and ethoxysilanes as external donors (ED) on propylene polymerization in liquid monomer with the supported titanium–magnesium catalyst (TMC) and on properties of the produced polypropylene (PP) are studied. Addition of the studied donors to the polymerization system significantly increases the PP isotacticity compare...

The influence of supported titanium-magnesium catalysts with various internal and external donors on the propylene polymerization in the liquid monomer medium and the characteristics of the polypropylene formed were studied. The following internal donors were used: dibutyl phthalate, diisobutyl phthalate, 9,9′-bis(methoxymethyl) fluorene, and dieth...

The influence of concentrations of the monomer, triethylaluminum, and hydrogen on the molecular mass of polyhexene obtained by polymerization of hexene-1 over a supported titanium-magnesium catalyst was studied. Ratios of rate constants of the transfer of polymer chain with the monomer, triethylaluminum (AlEt 3 ) and hydrogen to the rate constant o...

We present data on the number of active centers (CP) and the propagation rate constant (kP) upon copolymerization of ethylene and 1-hexene over supported titanium–magnesium catalysts of different compositions obtained by polymerization quenching with radioactive carbon monoxide (¹⁴CO). The rise in ethylene/1-hexene copolymerization rate as compared...

Specific features of formation of composite materials based on polyethylene, multi-walled carbon nanotubes, and cobalt nanoparticles (MWCNT–PE and Co/MWCNT–PE) by in situ polymerization were revealed. The in situ polymerization technique is based on ethylene polymerization on a highly dispersed Ti-containing catalyst supported on the surface of MWC...

The effect of hydrogen on the number of active centers (СР) and the propagation rate constant (kP) at ethylene polymerization over titanium–magnesium catalysts is studied using quenching by radioactive carbon monoxide (¹⁴СО). The polymerization rate drops after hydrogen was added to the polymerization medium mainly due to the decrease in the calcul...

A series of novel 2-[(arylimino)alkyl]pyridine derivatives, containing electron-withdrawing groups (F, Cl, Br, CF3, NO2, CN) in the aryl rings, have been synthesized and characterized by ¹H, ¹³C and ¹⁹F NMR spectroscopy. The corresponding nickel(II) complexes (24 complexes) have been prepared in good yields. The nature of the Ni complexes has been...

The data on content of individual fractions with different microtacticity for poly(propylene) (PP) samples produced over titanium–magnesium catalysts (TMCs) with composition TiCl4/MgCl2 and different titanium contents (0.1 and 3.5 wt%), as well as on the effects of pretreatment of these catalysts with triethylaluminum and addition of an external el...

The studies were focused on the influence of particle size of the Russian Ti-Mg catalyst IC-8-21 on the properties of polypropylene (PP) synthesized by polymerization of propylene in a liquid monomer medium. The catalysts with particles of 20 to 64 mm in size were shown to be highly active, identically sensitive to hydrogen and to provide synthesis...

This paper presents the analysis of rubberlike hyperbranched polyethylene (PE) deposits in separators and high-pressure (HP) recycle system with use of NMR spectroscopy 13С, X-ray phase analysis and differential scanning calorimetry; polymer extraction separation with boiling o-xylene and comparison of fraction characteristics have been carried out...

It was found that the observed order of the polymerization rate with respect to ethylene concentration at ethylene polymerization over two titanium-magnesium catalysts of different compositions is significantly higher than 1(1.6-2.1). The data on the effect of ethylene concentration on the number of active centers (C-p) and the propagation rate con...

The data on the effect of ethylene concentration on polymerization rate for several modifications of modern highly active titanium–magnesium catalysts TiCl4/MgCl2 are presented. These catalysts differ in titanium content and conditions of support preparation, activities, and the shape of kinetic curves. It is found that the observed order of polyme...

A comparative study of multiwalled carbon nanotube/polyethylene (MWCNT/PE) composites produced by different methods (thermal mechanical mixing, coagulation precipitation technique and in situ ethylene polymerization with a Ziegler–Natta catalyst supported on MWCNTs) has been performed. The morphology and structure of the produced composites were in...

The data on the effect of cocatalyst composition and polymerization conditions on activity and MWD of polyhexene (PH) produced over a high-activity titanium-magnesium catalyst are obtained. The cocatalyst has an extremely strong effect on the MWD of polyhexene. When triisobutylaluminum is used as a cocatalyst, PH with high Mw and narrow MWD is prod...

New data on the molecular weight characteristics of polypropylene (PP) and polyethylene (PE) were obtained from the polymerization over supported titanium–magnesium catalysts differing in their compositions (presence and absence of internal and external donors). Internal and external donors were found to affect the molecular weight of polymers in a...

The successive self-nucleation/annealing technique (SSA) by differential scanning calorimetry has been applied to study the heterogeneity of ethylene–hexene-1 copolymers produced with supported catalytic systems of different compositions: highly active supported Ziegler–Natta (Z–N) catalysts—a titanium–magnesium catalyst TiCl4/MgCl2 (TMC) and a van...

The number of active centers (СP) and propagation rate constants (kP) for ethylene polymerization with single-site homogeneous catalysts composed of cobalt (II) bis(imino)pyridine complexes: 2-tBuLCoCl2 and 2,5-tBu2LCoCl2 (L: 2,6-(C6H3NCMe)2C5H3N) and methylaluminoxane (MAO) as an activator have been determined by polymerization quenching with radi...

Separation into narrow MWD fractions (liquid–liquid fractionation) and preparative TREF (temperature rising elution fractionation) with subsequent analysis of fractions by GPC, FTIR, and 13C NMR spectroscopy were used to study the comonomer distribution of ethylene/1–hexene copolymers produced over highly active supported titanium‐ and vanadium‐mag...

Method of polymerization quenching with radioactive carbon monoxide (14СО) has been used to determine the number of active centers (С P ) and propagation rate constants (k P ) for ethylene polymerization over the homogeneous catalysts 2,6-R2LVCl3+MAO (L: 2,6-(C6H3N=CMe)2C5H3N, R=Me, Et). For both catalysts the maximum number of active centers at 60...

The data on the effect of polymerization duration on molecular weight (MW), molecular weight distribution (MWD), and content of α‐olefin were obtained for ethylene/1‐hexene copolymers produced on a supported titanium–magnesium catalyst (TMC) upon polymerization in the absence and presence of hydrogen. An increase in MW, narrowing of the MWD, and a...

The data on the effect of comonomer (propylene and 1‐hexene) on molecular weight (M w), molecular weight distribution (MWD), and content of terminal double bonds were obtained for ethylene/α‐olefin copolymers produced over a supported titanium–magnesium catalyst (TMC) upon polymerization in the absence of hydrogen. The experimental data on the effe...

In this paper, we synthesized a highly-dispersed MgCl2 support using the Grignard reagent method, and loaded it with TiCl4 and VCl4 to prepare polyethylene catalysts with titanium and vanadium active centers. The two catalysts demonstrated narrow particle distribution. The polymerization data demonstrated that the two catalysts both had good activi...

The data on the effects of polymerization duration, cocatalyst, and monomer concentrations upon ethylene polymerization in the absence of hydrogen, and the effect of an additional chain transfer agent (hydrogen) on the molecular weight (MW), molecular weight distribution (MWD), and content of vinyl terminal groups for polyethylene (PE) produced ove...

Catalysts for the polymerization of ethylene, which contain rac-Me2Si(Ind)2ZrCl2 (SBIZrCl2) bound to methylalumoxane-pretreated SiO2 supports (SiO2/MAO/SBIZrCl2), were studied with respect to leaching of zirconocene and MAO into heptane solutions caused by triisobutylaluminum (TIBA). The latter is found to solubilize surface-bound MAO and zirconoce...

The mechanical and rheological properties of ethylene α-olefin copolymers are governed by a molecular and supramolecular structure that depends on its molecular weight characteristics, comonomer concentration, and the uniformity of branching distributions for polymer chains with different molecular weights (compositional heterogeneity). Using state...

Summarized results are presented from studying the formation of the active component of supported Ziegler type catalysts, investigating the effect of the composition of these catalysts on the molecular mass characteristics of PE, and seeking new methods for producing catalysts with optimum morphology.

The chain transfer reaction with hydrogen at propylene polymerization over Ti-Mg catalysts (TMCs) of composition TiCl4/D1/MgCl2-AlEt3/D2 is studied in a wide hydrogen concentration range. A two-step mechanism of this reaction is suggested. This mechanism accounts for the fractional order of the reaction with respect to hydrogen concentration. Const...

The compositional heterogeneity of ethylene-1-hexene copolymers synthesized with various types of supported catalysts, namely, the titanium-magnesium catalyst TiCl4/MgCl2 and the zirconocene catalyst SiO2(MAO)/Me2Si(Ind)2ZrCl2, is studied via the method of successive self-nucleation-annealing (SSA) with the use of differential scanning calorimetry....

On the basis of new methods of synthesis of magnesium-containing carriers with the use of soluble organomagnesium compounds a wide spectrum of supported titanium-magnesium and vanadium-magnesium catalysts of various composition with controllable optimal morphology for obtaining versatile brands of polyethylene by suspension and gas-phase methods wa...

The effects of polymerization time and temperature on the molecular weight and molecular weight distribution of polyethylene, produced over homogeneous catalyst bis[N-(3-tert-butyl salicylidene)anilinato]zirconium(IV) dichloride tBu-L2ZrCl2/MAO have been studied. The data on the number of active centers (CP) and propagation rate constants (kP) at d...

Experimental data on the molecular weight distribution (MWD) of polyethylene (PE) produced over a broad number of Ziegler-Natta catalysts differing in composition and preparation procedure are presented. These catalysts include nonsupported TiCl3 catalyst, four types of supported titanium-magnesium catalysts (TMC) differing in the content of titani...

Noncatalytic ketonization of a nitrile-butadiene rubber (21mol% acrylonitrile units) by nitrous oxide was shown to yield polymeric products functionalized with carbonyl (mainly ketone) groups. The reaction was conducted in a benzene solvent at 180–230° and pressure of 3–6MPa. An assumed ketonization mechanism includes a 1,3-dipolar cycloaddition of...

Noncatalytic transformation of cis-1,4-polyisoprene rubber (Mn = 320,000) into functionalized liquid rubbers containing various amounts of carbonyl groups was studied. The process is performed via selective carboxidation of the polymer CC bonds by nitrous oxide (N2O) in the temperature range of 180–230°C and under 3–6 MPa pressure. The carboxidatio...

Heterogeneity of active centers (AC) of titanium‐magnesium catalysts (TMC) and vanadium‐magnesium catalyst (VMC) in ethylene‐hexene‐1 copolymerization has been studied on the base of data of polymer molecular weight distribution (MWD) deconvolution technique and copolymer fractionation onto narrow fractions. It was found that 3 and 4 Flory componen...

Results of a comparative study of ethylene polymerization activity and the structure of polyethylene (PE) produced over homogeneous catalysts based on bis(imino)pyridine complexes with close ligand frameworks and different transition metal centers (Fe(II), Co(II), Cr(III) and V(III)) are reported. The effects of the activator nature and polymerizat...

The number of active centers ( C P ) and propagation rate constant ( k P ) for ethylene polymerization with homogeneous catalyst LCoCl 2 + MAO and supported catalyst LCoCl 2 /SiO 2 + Al( i ‐Bu) 3 , where L is 2,6‐(2,6‐(Me) 2 C 6 H 3 N = CMe) 2 C 5 H 3 N, have been determined using the method of polymerization quenching by radioactive carbon monoxid...

The effect of chemical composition of highly active supported Ziegler-Natta catalysts with controlled morphology on the MWD of PE has been studied. It was shown the variation of transition metal compound in the MgCl 2 -supported catalyst affect of MWD of PE produced in broad range: Vanadium-magnesium catalyst (VMC) produce PE with broad and bimodal...

In this work, we investigated the influence of oxidation state of titanium and the effect of ethoxy groups' introduction into titanium compounds on the catalytic properties of MgCl2 - supported catalysts [with triisobutylaluminum (TIBA) or triethylaluminum (TEA) as cocatalyst] in ethylene polymerization and ethylene 1-hexene copolymerization, and o...

New experimental approach was used for analysis of molecular weight distribution (MWD) of polymers produced over titanium-magnesium catalysts (TMC). Polymers were fractionated on to fractions with narrow MWD (polydispersity (PD) values Mw/Mn ≤ 2). Then some of these fractions were combined to get the minimal quantity of fractions with PD values clo...

The effects of polymerization temperature, polymerization time, ethylene and hydrogen concentration, and effect of comonomers (hexene-1, propylene) on the activity of supported catalyst of composition LFeCl2/MgCl2-Al(i-Bu)3 (L = 2,6-bis[1-(2,6-dimethylphenylimino)ethyl] pyridyl) and polymer characteristics (molecular weight (MW), molecular-weight d...

The effect of Ti content on the activity of titanium–magnesium catalysts (TMC) and molecular weight distribution (MWD) of polyethylene (PE) produced has been studied. It was found that the activity enhances sharply as Ti content decreases from 0.6 to 0.07 wt %, and shows no significant changes in the Ti content range of 0.6–5.0 wt %. The maximum ac...

The number of active centers ( C P ) and propagation rate constants ( k P ) for polymerization of ethylene with supported catalysts LFeCl 2 /SiO 2 , LFeCl 2 /Al 2 O 3 and LFeCl 2 /MgCl 2 (L = 2,6‐(2,6‐(Me) 2 C 6 H 3 NCMe) 2 C 5 H 3 N), activated by an Al( i ‐Bu) 3 co‐catalyst, were determined by a method of polymerization inhibition with radioacti...

The article reports on the noncatalytic transformation of a polybutadiene (number-average molecular weight = 128,000) into a functionalized liquid rubber via the carboxidation of the polymer CC bonds by nitrous oxide. The reaction was conducted in a benzene solution at 160–230 °C and a pressure of 3–6 MPa. The carboxidation mechanism was determined...

Highly active supported vanadium-magnesium catalysts (VMC) produce polyethylene (PE) with broad and bimodal molecular mass distribution (MMD) in comparison with the famous titanium-magnesium catalysts (TMC). The effect of hydrogen as an efficient chain-transfer agent on the MMD of PE has been studied. Increasing hydrogen concentration causes a cons...

Method of polymerization inhibition by radioactive carbon monoxide ( ¹⁴ CO) has been used to determine the number of active centers ( C P ) and propagation rate constant ( k P ) for ethylene polymerization with homogeneous complex 2,6‐(2,6‐(Me) 2 C 6 H 3 NCMe) 2 C 5 H 3 NFeCl 2 (LFeCl 2 ), activated with methylalumoxane (MAO) or Al( i ‐Bu) 3 . Wit...

Data on ethylene polymerization over supported LFeCl2/MgCl2 catalysts {L = 2,6-bis[1-(2,6-dimethylphenylimino)ethyl]pyridyl} containing AlR3 (R = Me, Et, i-Bu, or n-Oct) as an activator are presented. These catalysts are highly active (100–300 kg of polyethylene/g of Fe h bar of C2H4) and stable in ethylene polymerization at 70–80 °C. Data on the e...

It was demonstrated that the treatment of polyethylene by nitrous oxide (N2O) at 230-250°C leads to selective oxidation of end double bonds of the polymer and their quantitative conversion into carbonyl groups. Oxidation has an insignificant effect on the molecular mass distribution of the polymer and may be regarded as a new method of PE modificat...

The data on the number of active centers in the ethylene polymerization with highly active supported vanadium-magnesium catalyst (130 kg-PE/g-V · h · bar) were obtained by using 14CO as a radioactive inhibitor. The number of active centers was found to attain 0.06 mol/mol-V and the propagation rate constant equaled 2.2 · 104 L/mol · s (80°C). The e...

The data on the number of active centers in the ethylene polymerization with highly active supported vanadium-magnesium catalyst (130 kg-PE/g-V·h·bar) were obtained by using 14CO as a radioactive inhibitor. The number of active centers was found to attain 0.06 mol/mol-V and the propagation rate constant equaled 2.2·104 L/mol·s (80°C). The effect of...

Ethylene polymerization on supported vanadium-magnesium catalysts with the composition VCl4/MgCl2 and VOCl3/MgCl2 was studied in the presence of hydrogen as the chain transfer agent. Vanadium-magnesium catalysts (VMC) are known to exhibit a high reactivity towards hydrogen. This reactivity is manifested as a sharp decrease in polyethylene (PE) mole...

Adsorption of NO as a probe molecule in infrared diffusion reflectance spectroscopy (DRIFTS) and X-ray photoelectron spectroscopy (XPS) have been used in order to identify surface vanadium species in vanadium–magnesium catalysts (VMC). The presence of V3+ and V4+ in VCl4/MgCl2 and V4+ in VOCl3/MgCl2 was shown by XPS and DRIFTS. However, DRIFTS has...

Catalyst activity was studied in a slurry polymerization of ethylene carried out over supported VCl4/MgCl2 and VOCl3/MgCl2 catalysts in relation to hydrogen concentration (0-40 mmols/L, i.e., 0-2 bar) and to Al(i-Bu)3 and Al(i-Bu)2H, each used as cocatalyst. Hydrogen was found to reduce the activity of the catalyst by 2 to 6 times. The deactivation...