It has been shown that catalytic systems of the type Cr(III)/TEA/L, where Cr(III) is tris(2-ethylhexanoate)chromium(III) (Cr(EH)3), tris(acetylacetone)chromium(III) (Cr(acac)3); TEA is triethylaluminum; L is 2,2′-bipyridyne (bipy), 1,10-phenanthroline (Phen), N,N′-bis-(cyclohexyl)diazabutadiene-1,3 (DCy-DABD) and N,N′-bis-(2,6-diisopropylphenyl)diazabutadiene-1,3 (DPPh-DABD), can be employed for ethylene poly- and olygomerization at 60–80 °C and under pressure 2–3 MPa. The proton affinity of the used bidentate nitrogen-containing ligands is evaluated using quantum chemical calculations. The DCy-DABD, which has the lowest basicity, turns out to be the best ligand for the selective di- and trimerization of ethylene.

The kinetics of the reaction of CO2 with propylene oxide utilizing a salenCrCl/PPNCl active catalytic system is studied with varying reaction conditions (temperature, pressure, and cocatalyst/catalyst ratio). The reaction proceeds selectively to form cyclic propylene carbonate (PC) at [PPNCl]/[salenCrCl] ratios above two. The value of the effective activation energy of PC formation is found.

The irradiation of low-density polyethylene with MeV protons leads to a substantial increase in surface free energy, its acid–base component, and surface polarity due to the appearance of functional groups in the surface layer, as confirmed by ATR IR and Raman spectra. It has been shown that the surface energy of the irradiated polymer depends little on the change in proton energy from 1 to 4 MeV at a fluence of 1015 proton/cm2. It has been found that the oxygen content of the irradiated polymer surface increases as a result of oxidative reactions of the radicals generated during radiolysis and the thermal stability of the polymer decreases.

Energy characteristics of the irradiated surface of a polytetrafluoroethylene film depend on the energy and fluence of bombarding MeV protons. Irradiation with 2–4 MeV protons leads to an increase in the surface free energy; 4 MeV protons at a fluence of 1015 proton/cm2 increase the polarity of the polymer surface by 40 times due to the appearance of functional groups, the polarity enhancement being manifested in an increase in the acid–base component of the surface energy by more than a factor of 50. There is a correlation between the dispersion component of the surface energy and the degree of crystallinity of the near-surface layer of the polymer a period. They both grow symbatically in the case of bombardment with 1–2 MeV protons and decrease upon irradiation with 4 MeV protons. It has been found that dehydrofluorination results in carbonization of the irradiated surface, a decrease in the fluorine content, and an increase in the proportion of oxygen due to oxidation of the radicals generated by proton bombardment.

We report the effect of preliminary γ-irradiation of polyethylene (PE) and ethylene-propylene copolymer (CEP) on the kinetics of polymer ablation under CO2 laser irradiation. The rate of PE ablation exceeds the rate of CEP ablation at all doses of γ-irradiation. The ablation rate of the polymers can be approximated by a linear function in the initial stage, and the rate reaches a constant value in the second stage of ablation. The rate of laser ablation increases linearly with the dose of preliminary γ-irradiation in both stages of the kinetics. For PE ablation, the duration of the linear increase in rate decreases with increase in preliminary radiolysis dose. The morphology of the crater surface formed during the laser ablation of γ-irradiated polymers is characterized by a more diverse structure.

The effect of polyketone (PK) γ-irradiation dose on the energy characteristics of the PK surface, the specific free surface energy, and the interfacial energy at the boundary between polar (water) and nonpolar (octane) liquids has been studied for the first time. The most significant changes in the energy characteristics of the surface occur at doses up to 100 kGy, and improvement in PK adhesion to the polar and nonpolar phases is observed at doses above 75 and 200 kGy, respectively.

The effect of the conditions (time, temperature, pressure, and cocatalyst/catalyst ratio) on the rate and selectivity of the reaction between СО2 and propylene oxide catalyzed by TPPCrCl and TPPCoCl (TPP is 5,10,15,20-tetraphenylporphyrin) has been studied. The time variation of the reaction rate has been analyzed by measuring the СО2 uptake during the reaction. The observed dependences of the reaction rate on the temperature and cocatalyst/catalyst ratio are similar for TPPCrCl and TPPCoCl. In the presence of TPPCoCl, the reaction yields a mixture of poly(propylene carbonate) and a cyclic carbonate, while when TPPCrCl is used, only the cyclic carbonate is synthesized.

Based on the analysis of scientific and patent literature published over the period from June, 2010 to February, 2016, data on catalytic metal complex systems on the basis of chromium with various degrees of oxidation in the reaction of selective tri- and/or tetramerization of ethylene have been systematized and described. Key information about catalytic systems exhibiting high selectivity for higher alpha-olefins (1-hexene and 1-octene) or their mixtures is surveyed.

The objective of this review is the analysis and comment of recent publication results (from July 2010 until February 2017) obtained for selective ethylene oligomerization toward 1-hexene and 1-octene catalyzed by chromium-based catalytic systems. Both the scientific and patent literature was taken into the consideration. The catalytic systems for ethylene oligomerization are classified on the basis of the ligand type employed. The activities and selectivities of the catalysts are provided throughout the text. Despite a big success in the field, there is still rather limited choice of catalysts affording simultaneously high activity, selectivity and low polymer proportion. This is especially true for ethylene to 1-octene tetramerization reaction. The results of the studies concerning oligomerization mechanisms obtained over the recent years are also included in this review.

The effect of the nature of a chromium(III) coordination compound and various substituted pyrrole ligands on ethylene oligomerization in the presence of a Cr(III) complex–pyrrole ligand (L)/AlEt3 catalyst system (CS), where Cr(III) is Cr(EH)3, Cr(асас)3, or CrCl3(THF)3 and L is pyrrole, 2-phenylpyrrole, 2-formylpyrrole, N-methylpyrrole, or N-vinyl-2-phenylpyrrole, has been studied. It has been shown that the most significant effect on the behavior of the CS is exerted by the nature of the ligand involved in the formation of the CS. The acid–base properties of the employed ligands have been determined by quantum-chemical calculations. The data obtained have revealed that selectivity of the catalyst system depends on the ligand basicity.

Методом калориметрии сгорания определена энергия сгорания тройного сополимера монооксид углерода-этилен-бутен-1 с содержанием бутановых фрагментов 14,6 мол. %, рассчитаны энтальпия сгорания и стандартные термодинамические параметры образования при температуре 298,15 К. По полученным, а также литературным данным рассчитаны стандартные термодинамические параметры синтеза сополимера в области температур от Т → 0 до 400 К.

The topologically diblock structure of a tetrafluoroethylene—hexafluoropropylene copolymer with a total weight fraction of crystalline structures of 0.07 is transformed into a fully amorphous matrix with a pseudo-network structure after irradiation with 1—4 MeV protons. Instead of crystalline branching points (as in the unirradiated copolymer), cluster structures have appeared in the matrix. Oxidative degradation processes that occur during the bombardment result in significant functionalization of the copolymer and a substantial increase in the surface free energy, its acid—base component, and surface polarity.

The heat capacity, temperatures and enthalpies of the physical transformations of a triple alternating copolymer of carbon monoxide with ethylene and butene-1 with a 46 mol % concentration of butane fragments are studied via adiabatic and differential scanning calorimetry in the region of 6−570 K. Its combustion energy in a condensed state at T = 298.15 K is measured calorimetrically. Standard thermodynamic functions of the copolymer in the region of T → 0 to 400 K and the thermodynamic characteristics of its formation at T = 298.15 K and synthesis within the range of T → 0 to 400 K are calculated. The dependences of the thermodynamic properties of the copolymer on the concentration of butane fragments in the macromolecules are obtained.

The temperature dependence of the heat capacity for partially crystalline polyketone derived from carbon monoxide with ethylene and butene-1 (the butane units content is 14.6 mol %) was studied over the range 6–520 K by the methods of precision adiabatic vacuum calorimetry and differential scanning calorimetry. Thermodynamic characteristics of the glass transition and glassy state and melting characteristics were determined. The standard thermodynamic functions, namely, and , were calculated for the temperature range from T → 0 to 400 K, based on the experimental data. Thermal stability temperature for polyketone (520 K) has been specified by the thermogravimetry method