Liquid-phase isobutane alkylation with butenes over aluminum chloride complexes synthesized in situ from activated aluminum and <Emphasis Type="Italic">tert</Emphasis>-butyl chloride

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.     

Mechanochemical synthesis of nanocrystalline nickel-molybdenum compounds and their morphology and application in catalysis: III. Catalytic properties of massive Ni-Mo sulfide catalysts synthesized using mechanochemical activation

The precursors of massive Ni-Mo catalysts for hydrotreating processes, which were synthesized by the mechanochemical activation of a mixture of nickel hydroxocarbonate NiCO₃·2Ni(OH)₂·nH₂O and ammonium paramolybdate (NH₄)₆Mo₇O₂₄ · 4H₂O, were sulfidized. Their structure was studied by X-ray diffraction analysis and high-resolution electron microscopy. It was found that MoS₂ packets, which are characterized by the presence of structural defects and geometric curvature, are the constituents of the massive catalysts. The catalyst also includes a phase of Ni₃S₂ and regions containing a complex Ni-Mo-S phase. The catalytic tests of the synthesized catalysts in the model reactions of 1-methylnaphthalene and dibenzothiophene conversions showed that the catalyst whose precursor was a heteropoly compound with the Anderson structure after the stage of mechanochemical activation exhibited the highest activity.     

Oxidation of cyclohexene and α-pinene with O2—H2 mixture in the presence of supported platinum or palladium catalysts

Oxidation of cyclohexene and -pinene with an O₂—H₂ mixture in the catalytic systems containing Pt or Pd and heteropoly compounds (HPC) was studied. The main oxidation products are epoxides, allyl alcohols, and ketones. The highest yield of the oxidation products was obtained in the presence of the platinum catalyst in combination with HPC PW₁₁ or PW₁₁Fe. The reaction mechanism was proposed. A relationship between the HPC composition and the nature of intermediates involved in oxidation was examined.     

Palladium(II), Copper(II), Iron(III), and Vanadium(V) Complexes with Heteropolyanion PW9O9–34: 31P, 183W, 51V NMR and IR Spectroscopy Studies

The formation of Pd(II)-containing and mixed Pd(II),Cu(II), Pd(II),Fe(III), and Pd(II),V(V) complexes with heteropolyanion PW₉O^9– ₃₄was studied using ³¹P, ¹⁸³W, ⁵¹V NMR, visible UV and IR spectroscopy, and the differentiating dissolution methods. In an aqueous solution and at optimal pH (3.7), the monometallic complexes [Pd₃(PW₉O₃₄)₂]^12–and [Pd₃(PW₉O₃₄)₂Pd _n O _x H _y ] ^q–(n _av= 3), the bimetallic complexes [Pd₂Cu(PW₉O₃₄)₂]^12–, [Pd₂Fe(PW₉O₃₄)₂]^11–, and [PdFe₂(PW₉O₃₄)₂]^10–, and a mixture of the [Pd₃(PW₉O₃₄)₂Pd _n O _x H _y ] ^q–(n _av 10) + [(VO)₃(PW₉O₃₄)₂]^9–complexes are formed. The title complexes were isolated from solution as Cs⁺solid salts belonging to the same [M₃(PW₉O₃₄)₂] structural type.     

Liquid-phase hydrodechlorination of polychloroaromatic compounds in the presence of Pd-promoted nickel catalysts

Liquid phase hydrodechlorination of chlorobenzene, 1,2,4-trichlorobenzene, hexachlorobenzene, polychlorinated biphenyls in the ethanol-containing solution, on Me⁰/C (where Me⁰-Pd, Ni or bimetallic Ni−Pd; C-carbon material “Sibunit”) with H₂ have been studied at 20–70°C and P_{H 2}=1–50 atm. Pd and Pd-promoted Ni catalysts exhibit the highest activity. Kinetic studies show hydrodechlorination of these compounds to be a consecutive reaction, which under the conditions described may produce less chlorinated compounds.     

Pt catalyst for the liquid-phase epoxidation of cyclohexene with an O2/H2 mixture

Conditions are found for the preparation of Pt catalysts providing the formation of epoxy-derivative in the reaction of cyclohexene with an O₂/H₂ mixture.

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Pt .

     

Catalytic properties of palladium complexes with silica-anchored phosphine ligands in vinyl exchange reaction

Catalytic properties of Pd complexes with phosphine ligands anchored to silica have been studied. The valence state of Pd and the acidity of the alcohol were found to influence the rate of vinyl exhange. A possible reaction mechanism is proposed.

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Synthesis and Study of Nanodispersed Carbon in the Combustion of Acetylene in a Flow Detonation Tube

Nanodispersed carbon was obtained via high-temperature combustion of acetylene–oxygen mixtures in a flow-through tubular chamber in cyclic detonation waves (“pulsed detonation”) at a constant propagation velocity (D_det ≈ 2150 m s^–1). It was found that the position of a plateau in the curve describing how the detonation velocity depends on the content of oxygen in the starting detonation mixture in the range 15–30% coincides with the range of descending branches of the dependences of the specific adsorption surface area and adsorption of dibutyl phthalate by aggregated particles. Various physicochemical methods of analysis (X-ray diffraction analysis, Raman spectroscopy, high-resolution transmission electron microscopy, etc.) were used to comparatively examine the properties of nanodispersed carbon and of the known industrially produced domestic and foreign brands of technical-grade carbon. The conditions were found in which detonation nanocarbon particles are obtained in a certain range of parameters of micro- and macrostructures with improved morphology and basic electrical properties.