Search

A method for carbon materials synthesis based on polyvinyl chloride has been proposed. Method includes polymer dehydrochlorination by alkali with carbon-rich conjugated structures (polyvinylenes) formation and its subsequent carbonization at relatively low temperatures. Raman and 13C NMR spectroscopy and transmission electron microscopy show that thermal treatment of the resulting polyvinylenes up to 400 °C leads to the formation of amorphous carbon material with chlorine contain less than 0.5 wt.%. These results can be used to develop dioxin-free technology of utilization of polyvinyl chloride and its wastes.

The composition of the products of the combined conversion of various naphthenic hydrocarbons and fatty acids has been studied. It was determined that the distribution of the cracking products of model mixtures is largely dependent on the unsaturation of the hydrocarbon chains of fatty acids. It was found that at a content of oleic acid of 5 wt % in the model mixtures the changes in the conversion of cyclohexane, methylcyclohexane and decalin almost do not occur. With increasing the content of the unsaturated fatty acid up to 25 wt % the effect of inhibition of cracking of the hydrocarbons was observed. Upon combined conversion of tetralin and oleic acid a decrease in hydrocarbon conversion was not observed. According to the results of combined transformations of naphthenes with stearic acid it was found that a high content (25 wt %) of a saturated fatty acid in the model mixture does not result in a sharp decrease in the hydrocarbon conversion.

A set of aluminum–nickel alloys has been studied. The elemental composition of the samples has been determined by atomic emission and atomic absorption spectrometry. X-ray diffraction analysis has revealed that the alloying of the metals leads to the formation of Al3Ni and Al3Ni2 intermetallic compounds, while a portion of Al remains in a metallic phase. The local chemical composition and surface morphology of the original alloys and the alloys activated with the liquid Ga–In eutectic have been studied by scanning electron microscopy and X-ray microanalysis. It has been shown that the original alloys are characterized by a pronounced morphological heterogeneity of interfacial regions in the near-surface layers. It has been found that the studied Al–Ni alloys are activated by the liquid Ga–In eutectic; however, one of the alloy components—the Al3Ni intermetallic compound—does not undergo significant morphological and chemical changes in contact with the liquid eutectic.

Mechanochemical activation of PVC in a high-energy centrifugal-planetary mill was shown to increase its reactivity in dehydrochlorination under the action of bases. Thus modified PVC is capable of low-temperature carbonization and can form a carbon material even at the temperatures below 400°C.

Chlorine-substituted polymers with a system of conjugated double bonds—polyvinylene chlorides, which were prepared by the chemical dehydrochlorination of carbon-chain chloropolymers with a Cl content of higher than 60 wt %, being polymeric electron acceptors, were found to form complexes with alkali metal hydroxides (LiOH, NaOH, and KOH). The resulting complexes exhibit high sorption capacity for phenol. The static exchange capacity of the alkaline complexes of polyvinylene chlorides for phenol is as high as 310 mg/g in an aqueous medium or 90 mg/g in an atmosphere of air; these values are comparable with the sorption capacity of the known sorbents of phenol.

A high-energy planetary mill AGO-2 was used for mechanical activation of synthetic graphite with the particle size of 25–30 μm and specific surface area S BET = 3.0 m 2 /g in air for 1–60 min at a 100 g acceleration of milling bodies. The X-ray diffraction, Raman spectroscopy and electron microscopy studies showed that the 60 min mechanical activation of graphite decreases the number of graphene layers in graphite crystallites to 8–12 and induces their turbostratic disorder. The size of graphite particles decreases to 6.9 μm after 30 min of mechanical activation and increases to 12.1 μm when the time of mechanical activation is extended to 60 min. Similar changes are observed for the true density of graphite: after 60 min of mechanical activation it becomes equal to 2.48 ⋅ 10 3 kg/m 3 , which is by 10% higher than the true density of graphite not subjected to such treatment. The specific adsorption surface of graphite ( S BET ) reaches its maximum values, 427–460 m 2 /g, after 7–12 min of mechanical activation. A further increase in the activation time to 30–60 min decreases S BET of graphite to 230–250 m 2 /g. Due to attrition of steel milling bodies caused by mechanical activation, iron is accumulated in the samples and its content exceeds 5%. Iron is distributed uniformly in the graphite as the 30–100 and 3–5 nm particles of hematite and iron carbide. The IR spectroscopy study revealed the formation of 0.8 mEq/g of the hydroxyl, phenolic, lactone and carbonyl groups on the graphite surface in the course of mechanical activation.

Studies of the structural transformations of carbon black caused by laser and electron irradiation have been carried out using high-resolution transmission electron microscopy (HRTEM). The heterosystems of the Pt/C-type are obtained in the process of laser irradiation of carbon black suspensions in platinum-containing solutions. A high-energy electron irradiation of carbon black causes the formation of multimorphological carbon nanostructures, which possess a graphite-like arrangement of graphene layers.

The structural, morphological, and chemical characteristics of aluminum-copper alloys before and after contact with the liquid Ga-In eutectic have been studied. X-ray diffraction (XRD) analysis has revealed that alloying results in the formation of Al9Cu11.5 and Al2Cu intermetallic compounds and CuAl0.005, CuAl0.14, and AlCu0.004 substitutional solid solutions. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) have shown that, for the CuAl0.005 and CuAl0.14 substitutional solid solutions of aluminum in copper and the individual Al9Cu11.5 intermetallic compound in contact with the liquid Ga-In eutectic, surface spreading of the eutectic without any significant morphological and chemical changes in the studied systems is observed. At the same time, the alloy containing the Al2Cu intermetallic compound and the phase of the AlCu0.004 substitutional solid solution of copper in aluminum interacts with liquid Ga-In eutectic owing to the activation of aluminum as a solid solution component. This activated Al-Cu alloy reacts with liquid tert-butyl chloride in the presence of ethylene to form catalyst Al-Cu-Cl complexes in situ. It has been speculated that these complexes are mostly formed owing to the dissolution of the phase of the AlCu0.004 substitutional solid solution of copper in aluminum in a medium of liquid tert-butyl chloride.

s Thermal decomposition of Mg–Al and Ni–Al layered double hydroxides LDH at temperatures lower than 800 °C leads to the formation of oxides with different structures. Mg–Al oxide has a very defective structure and consists of octahedral layers as in periclase MgO and mixed octahedral–tetrahedral layers as in spinel MgAl 2 O 4 . Mixed Ni–Al oxide has a sandwich-like structure, consisting of a core with Al-doped NiO-like structure and some surface layers with spinel NiAl 2 O 4 structure epitaxial connected with the core. Suggested models were verified by simulation of X-ray diffraction patterns using DIFFaX code, as well as HRTEM, IR-, UV-spectroscopies, and XPS.

Nanocapsules and stacks of graphene sheets have been prepared from carbon black by irradiation relativistic electron beam. Electrons with energy of 2.5 MeV were used in these experiments to produce carbon nanoparticles with graphite-like structure of the graphene layers. High Resolution Transmission Electron Microscopy (HRTEM), Raman spectroscopy and Electron Spin Resonance (ESR) spectroscopy were used to obtain the information about morphology, crystallinity, and interlayer distance of these nanostructures.

Some catalysts of CO oxidation on silumin alloy AK12M2, used for the manufacture of pistons for Russian cars were investigated. The catalysts were prepared by the method of plasma electrolytic oxidation of silumin in electrolytes of various compositions with further activation by the salts Ce, Cu, Co, Ni, Mn and Al. The catalytic tests were carried out in a flow reactor in a mixture of 1% CO and 99% air, with the temperature range of 25-500 °C. The most active catalysts in CO oxidation are those activated with Ce and Cu salts on silumin, treated for 3 hours in an electrolyte containing 4 g/l KOH, 40 g/l Na2B4O7 (conversion of CO is 93.7% at a contact time of 0.25 s). However, the catalysts obtained from silumin treated in the electrolyte containing 3 g/l KOH, 30 g/l Na2SiO3 are more suitable for practical usage. Because when the treatment time of those catalysts is 10 – 20 minutes it is possible to achieve comparable CO conversion. The morphology and composition of the catalysts were studied by the methods of a scanning electron microscope with energy-dispersive surface analysis and X-ray phase analysis. The surface of the non-activated sample consists of γ-Al2O3 and SiO2 particles, due to which the active components get attached to the support. CeO2 and CuO are present on the surface of the sample with the active component.Some catalysts of CO oxidation on silumin alloy AK12M2, used for the manufacture of pistons for Russian cars were investigated. The catalysts were prepared by the method of plasma electrolytic oxidation of silumin in electrolytes of various compositions with further activation by the salts Ce, Cu, Co, Ni, Mn and Al. The catalytic tests were carried out in a flow reactor in a mixture of 1% CO and 99% air, with the temperature range of 25-500 °C. The most active catalysts in CO oxidation are those activated with Ce and Cu salts on silumin, treated for 3 hours in an electrolyte containing 4 g/l KOH, 40 g/l Na2B4O7 (conversion of CO is 93.7% at a contact time of 0.25 s). However, the catalysts obtained from silumin treated in the electrolyte containing 3 g/l KOH, 30 g/l Na2SiO3 are more suitable for practical usage. Because when the treatment time of those catalysts is 10 – 20 minutes it is possible to achieve comparable CO conversion. The morphology and composition of the catalysts were studied by the method...

The effect the chemical composition of a support, the content of nickel, and the method of its binding has on the physicochemical and catalytic properties of the NiO/B2O3-Al2O3 system is studied. The boron oxide content in the support is varied from 2 to 30 wt %, while the nickel concentration is 0.59–3.18 wt %. The catalyst samples are studied via X-ray diffraction analysis, temperature-programmed desorption of ammonia, IR spectroscopy (including that of adsorbed CO), and UV-VIS diffuse reflectance spectroscopy. Tests of the catalysts in ethylene oligomerization are conducted in a fixed-bed flow reactor at a temperature of 200°C, a pressure of 1 MPa, and a space velocity of ethylene of 0.5 h−1. The feedstock is an ethylene-methane gas mixture containing 30 wt % of ethylene. It is suggested that the activity of the NiO/B2O3-Al2O3 system in ethylene oligomerization can be attributed to the formation of octahedral Ni2+ cations environed by borate anions on the surface of the system. The most active catalysts contain 2–3 wt % Ni and 10–20 wt % B2O3 in the supports. The method of preparation (adsorption binding or impregnation) has little effect on the state of nickel in the NiO/B2O3-Al2O3 system samples and their catalytic properties. The prepared catalysts are characterized by the ease of preparation, availability, and a low cost of the initial materials, as compared to known catalysts.

The liquid-phase interaction between isobutane and butenes at 303 K and 2.5–3.0 MPa has been investigated using activated aluminum (Al*)-tert-butyl chloride (TBC) model system (TBC: Al* = 0.35−4 mol/mol). It has been demonstrated by attenuated total reflection FT-IR (ATR-FT-IR) spectroscopy that the catalytically active aluminum chloride complexes forming in situ in the hydrocarbon medium vary in composition. Alkylation as such takes place at equimolar proportions of the reactants (TBC: Al* = 1: 1) and butenes feed 1mass flow rate of 5 h−1 per gram of Al*. According to ATR-FT-IR data, the most abundant aluminum complexes resulting under these conditions are the AlCl4− and Al2Cl7− ions and, probably, the molecular complex AlCl3 · sec-C4H9Cl. In a fourfold excess of TBC over Al* at butenes mass feed rate of 2.5 h−1, isobutane undergoes self-alkylation. In this case, the Al2Cl7− ion is not detected and the most abundant complexes are AlCl4−, Al3Cl10− and the molecular species AlCl3 · tert-C4H9Cl. It is hypothesized that the Al2Cl7− ion plays the key role in the liquid-phase alkylation of isobutane with butenes.

The properties and state of platinum in Pt/SO42−-ZrO2-Al2O3 catalysts with various alumina contents have been investigated in benzene hydrogenation as a model reaction using IR spectroscopy, temperature-programmed reduction, and H2 chemisorption. As the Al2O3 content is raised, the hydrogenating activity of the catalyst increases, which is due to the increasing proportion of metallic platinum on the surface.

Mechanochemical activation in high-energy planetary activators was used for the preparation of highly dispersed nickel-molybdenum compounds. Nickel hydroxocarbonate [NiCO3 · 2Ni(OH)2 · nH2O] and ammonium paramolybdate [(NH4)6Mo7O24 · 4H2O] were chosen as starting compounds. The effect of the Ni: Mo atomic ratio on the composition and structure of products formed in the process of mechanochemical activation followed by calcination was studied. It was found that, at the Ni: Mo atomic ratios of 1.0 and 1.4, the mechanically activated product after calcination at 520°C contained 70–100% β-NiMoO4, which is a stable phase at temperatures lower than 180°C.

The interaction between tert-butyl chloride and activated aluminum was studied by attenuated total reflectance Fourier transform infrared spectroscopy near room temperature (18–25°C). A long induction period of ∼240–260 min was observed. The ionic aluminum chloride complexes [Al n Cl3n+1]− (n = 1, 2) and the molecular species AlCl3 were identified at the activated aluminum/tert-butyl chloride interface during the reaction. The formation of the ion in the AlCl 4 − ion in the liquid medium and the presence of the same ion and a molecular AlCl3-tert-butyl chloride complex in the resinous products of the reaction were confirmed by 27Al NMR spectroscopy. The reaction products were analyzed qualitatively by GC/MS. The reactivities of activated aluminum and anhydrous aluminum chloride toward tert-butyl chloride under the same conditions were compared. A distinctive feature of the interaction activated aluminum and tert-butyl chloride is the dominant formation of the AlCl 4 − ion. By contrast, the interaction between aluminum chloride and tert-butyl chloride yields the polynuclear ion Al2Cl 7 − and, likely, Al3Cl 10 − .

The samples of the NiO/B2O3-Al2O3 system with NiO contents from 0.48 to 38.30 wt % were synthesized by the impregnation of borate-containing alumina (20 wt % B2O3). It was found that nickel oxide occurred in an X-ray amorphous state in the samples containing to 23.20 wt % NiO. At a NiO content of 4.86 wt % or higher, the support was blocked by the modifier to cause a decrease in the specific surface area from 234 to 176 m2/g and in the amount of acid sites from 409–424 to 333 μmol/g. An extremal character of the dependence of catalyst activity in ethylene oligomerization on NiO content was found with a maximum in the range of 4.86–9.31 wt %. Based on spectroscopic data, it was found that ethylene activation on the NiO/B2O3-Al2O3 catalyst can be associated with the presence of Ni2+ cations, which chemically interact with the support. The catalyst containing 4.86 wt % NiO at 200°C, a pressure of 4 MPa, and an ethylene supply rate of 1.1 h−1 provided almost complete ethylene conversion at the yield of liquid oligomerization products to 90.0 wt %; the total concentration of C8+ alkenes in these products was 89.0 wt %.

The oxidation of a carbon-carbon composite sorbent by a number of oxidants results in the variations of the chemical nature of the surface, including an increase in the overall content of surface oxygen-containing groups and, in separate cases, increased variations in its structure-chemical characteristics, primarily in an increase in the percentage of large mesopores. The oxidative modification of the initial sorbent increases the hydrophilicity of its surface and enhances the specific sorption of water vapors.

The interaction of nickel hydroxocarbonate, ammonium paramolybdate, and ammonium metatungstate (Ni: Mo: W = 3: 1: 1) is reported. Under mechanical activation conditions, nickel hydroxocarbonate particles undergo comminution and ammonium paramolybdate and ammonium metatungstate particles soften and aggregate. It is demonstrated by DTA, X-ray diffraction, and IR spectroscopy that heat treatment of the mechanically activated mixture at 400–450°C yields the salts NiMoO4 and NiWO4.

The conversions of a mixture of platinum(IV) and palladium(II) chloro complexes in aqueous solution and on the γ-Al2O3 surface at 25–150°C are reported. Heat treatment can initiate interaction between the complexes, both dissolved and adsorbed. The hydrolysis of the chloroplatinate ion is accelerated by the palladium chloro complex, whose composition remains unchanged.

The interaction of platinum(IV) and palladium(II) chloro complexes with the γ-Al2O3 surface in a wide range of surface metal concentrations is reported. Varying the concentration of the adsorbed metal complex on the alumina surface causes changes both in the proportions of weakly and strongly bound desorbable platinum species and in the proportions of desorbable (ion-exchanged) and nondesorbable (coordinatively bound) complexes. The adsorbed palladium complexes are more uniform in chemical composition and binding strength and consist largely of desorbable species removable from the surface by competitive sorption of anions. The absolute amount of coordinatively bound platinum and palladium species increases as the total metal content of the sample is raised to 1.0% and remains almost invariable at higher metal contents.

The oxide layers on the surface of aluminum metal and the aluminum alloys AD-1 and A-5 have been studied by attenuated total reflection infrared spectroscopy. The Al-O and Al-OH surface vibrational modes and A-O modes of the AlO4 and AlO6 groups have been identified. The structural inhomogeneity of the surface oxide layers is shown to contribute to their disruption when the sample is brought into contact with the liquid In-Ga eutectic. In situ scanning electron microscopy and X-ray microanalysis have been used to follow the dynamics of oxide layer disruption and the morphological and compositional changes in the eutectic alloy and the surface layer of aluminum.

The influence of hydrothermal treatment conditions (temperature, duration, acidity of the medium) on the structural and chemical transformations of the complex H2[Pt(OH)6] was studied. The composition and structure of the resulting compounds were determined by several physicochemical methods. Thermal analysis coupled with mass spectrometry showed that, as the hydrothermal treatment temperature is raised from 25 to 120 and 150°C, the product composition in terms of empirical formulas changes as follows: PtO2 · 4H2O → PtO2 · 3.5H2O → PtO2 · 1.5H2O. X-ray diffraction and UV and IR spectroscopy demonstrated that the changes in the chemical composition are accompanied by the amorphization of the structure and Pt-O bond strengthening. X-ray structure determination using the radial electron density distribution method showed that polynuclear species ∼10–15 A in size with a structure similar to that of orthorhombic PtO2 form in the complexes subjected to “hard” hydrothermal treatment (T ≥ 150°C).

Catalysts based on metals (Pt, Pd) and metal oxides (NiO, Co3O4, MoO3, WO3), supported on the surface of borate-containing aluminum oxide (B2O3–Al2O3), in the hydrocracking of sunflower oil at a temperature of 400°C, a pressure 4.0 MPa and a mass hourly space velocity MHSV 5.0 h–1 are compared. H2 TPR and IR spectroscopy of adsorbed CO and ESDR show that the hydrogenation catalyst components are Pt0 and Pd0, a mixture of Ni2+ + Ni0, Co2+ + Co0, or a mixture of the highest and partially reduced oxides of Mo and W. It is established that catalysts containing Pt, Pd, NiO and Co3O4, ensure complete oil hydrodeoxygenation. The main oxygen removal reactions in Ptand Pd-systems are decarboxylation and hydrodecarbonylation. For catalysts with NiO and Co3O4, characteristic reactions are reduction and methanation. The highest yield of the diesel fraction was obtained on Pt/B2O3-Al2O3 catalysts with metal contents of 0.3–1.0 wt %. Along with n-alkanes, the diesel fractions obtained on these catalysts include cycloalkanes and iso-alkanes (up to around 40 wt %) and aromatic hydrocarbons present in trace amounts. Hydrocracking on the Pt system at 400°C for 20 h with MHSV of 1.0 h–1 produces a diesel fraction with a yield of at least 82.0 wt % and the content of iso-alkanes at least 76.1 wt %.

Analytic results for final state corrections to the differential and total cross-section for e+e−→massive fermions are presented. In the phase space integration a cut 011 the photon energy was included. The numerical importance of the obtained results is shown for QED and QCD corrections to r, b and t-quark production. Final state corrections are changed considerably by applying a cut on the photon energy. All results are immediately applicable to theories with several neutral gauge bosons.

NLO QCD corrections to charged and neutral current Drell-Yan processes and their implementation in the computer system SANC are considered. On the partonic level both quark-antiquark and quark-gluon scattering channels are taken into account. Subtractions of the collinear singularities in the massive case are compared with ones in the MS-bar scheme. Results of SANC on the hadronic level are presented. Comparison with results of the MCFM package is shown., Comment: 16 pages, 2 figures

The paper examined the catalysts of low-temperature ammonia synthesis Ru-Cs/Sibunit in which Sibunit, mesoporous carbon carrying agents, vary considerably in specific surface area and pore volume, but the pore sizes are similar. According to Raman spectroscopy, the Sibunit structures are same. Applied ruthenium dispersiveness, determined by CO chemisorption, are also close (∼ 13 - 16%) for all the examined catalysts. The difference in the activity of the samples is due to the different direct contact probability of the particles of ruthenium and modifier (CsO x ). This probability decreases with increasing specific surface area ( S BEТ Sibunit) that are supposed to cause the decrease of catalyst activity on high-superficial Sibunit in the ammonia synthesis reaction.

A simple model of heavy leptons with strong interactions is proposed for ψ particles and di-muon production in ν interactions.

Bei der Reaktion des 2-Methyl-3,4,5-triphenylcyclopentadienons (I) mit den Phosphorverbindungen (II) entstehen die Anlagerungsprodukte (III).