Structure of Pt/ZnAl2O4 catalysts

The effect of the support preparation technique (solgel and coprecipitation) on the final Pt/ZnAl₂O₄ catalyst is presented. The structural properties of the solids obtained are correlated to the selectivity and activity for isobutane dehydrogenation in H₂ and He reaction media. If a highly dispersed catalyst is suitable, the support has to be prepared by the sol-gel method.

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( — ) Pt/ZnAl₂O₄. H₂ He. , — .

     

Catalysts for metathesis of olefins obtained through [Mo3O4(C2O4)3 (H2O)3]2? coordinated to γ-Al2O3

New highly active catalysts for the metathesis of olefins have been obtained through the interaction of [Mo₃O₄ (C₂O₄)₃ (H₂O)₃]^2– anion with Al₂O₃ surface and further activation in H₂ or CO atmosphere.

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[Mo₃O₄ (C₂O₄)₃ (H₂O)₃]^2– Al₂O₃ H₂ CO .

     

Partial oxidation of methane on Cr2O3/Al2O3

The oxidation of methane on supported chromia was studied at temperatures varying between 423 and 743 K and CH₄/O₂ ratios between 1 and 9 in a differential reactor. The main reaction products observed were carbon monoxide and formaldehyde. The rates of reaction obey a power law expression.

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, 423 743 CH₄/O₂ 1 9, . . .

     

Catalytic oxidative hydrolysis of H2PO2? anions in the presence of RhCl3

Kinetics of H₂ evolution in the RhCl₃–NaH₂PO₂–HCl–H₂O system has been studied. As found by³¹P NMR, Rh(I) complexes with the Rh–P(OH)₂O^– bond are formed and play the role of catalysts in the subsequent H₂ evolution reaction.

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H₂ RhCl₃–NaH₂PO₂–HCl–H₂O. ³¹P Rh(I) Rh–P(OH)₂O^–, H₂.

     

Kinetic studies of thiolane synthesis from tetrahydrofurane and H2S

Kinetic studies of tetrahydrofuran reaction with H₂S were carried out in a flow-circulation reactor. Presumably, the reaction takes place through dissociative chemisorption of reactants and the interaction of surface structures formed to produce thiolane and water. A kinetic equation that agrees with the suggested mechanism has been derived.

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- H₂S. , . , .

     

Kinetics of SO2 oxidation on K2S2O7?V2O5 catalyst in non-steady conditions

Studies of SO₂ oxidation on a molten component of vanadium catalysts in non-steadystate conditions indicates that the kinetics agree fairly well with an oxidation-reduction mechanism. In the low temperature range (<790 K) tetravalent vanadium can be partially crystallized.

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. , - . ( 790 ) .

     

Peculiarities of propylene metathesis over catalysts prepared by anchoring of Mo(V) oxalate to γ-Al2O3

Propylene metathesis over catalysts prepared by coordination of Mo(V) oxalate to -Al₂O₃ has been studied.

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, (V) -Al₂O₃.

     

Study of selective dissociation in C6F5H?C6F5D mixtures induced by intense CO2 laser pulses

Irradiation of a C₆F₅H–C₆F₅D mixture at 1 Torr by a tunable CO₂ pulse laser brings about chiefly dissociation of one component depending on the frequency of emission absorbed by the proper molecules. The addition of radical acceptors increases the selectivity by suppressing secondary reactions.

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C₆F₅H C₆F₅D 1 CO₂-, , . .

     

Sensitization of the photoadsorption of O2 and NO on SnO2

Photoadsorption activity of SnO₂ with respect to O₂ and NO after CO chemisorption has been revealed to be drastically increased. Photoadsorption is suggested to be sensitized by surface carbonates formed due to CO chemisorption.

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. , .

     

A new method for preparation of Mo/Al2O3 catalysts for olefin metathesis

A new method of preparation of highly active catalysts for metathesis of -olefins through the anchoring of [Mo₂O₄(C₂O₄)₂(H₂O)₂]^2– anion to the surface of -Al₂O₃ with further thermal activation in H₂ and CO is proposed.

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- [Mo₂O₄(C₂O₄)₂(H₂O₂]^2– -Al₂O₃ H₂ CO.

     

High-temperature reduction of SO2 by methane at various CH4/SO2 ratios

The character of the effect of initial reaction mixture and temperature on the selectivity of catalytic reduction of sulfur dioxide by methane in the presence of oxygen has been studied.

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.

     

Decomposition of N2O over CuxMg1?xAl2O4 catalysts

The results show that there is not difference between the catalytic activities of two series of Cu_xMg_1–xAl₂O₄ catalysts, despite a small but significant difference in cation distribution. The activity is mainly affected by the presence of CuO.

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, , , , - Cu_XMg_1–XAl₂O₄. CuO.

     

Structural changes of NaX zeolite during the H2S+O2 reaction

Infrared spectra in the 600, 700, and 1000 cm^–1 regions and X-ray investigations indicate that during H₂S+O₂ reaction in the temperature region of 293–473 K partial dealumination of the NaX zeolite crystal structure occurs. The dealumination increases with reaction temperature.

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- 600, 700 7000 ^–1 , H₂S+O₂ 293–473 NaX. .

     

The activity of Ni/AlPO4, Ni/AlPO4?Al2O3 and Ni/AlPO4?SiO2 catalysts in the hydrogenation of e-cinnamaldehyde

Liquid-phase catalytic hydrogenatio of E-cinnamaldehyde was carried out by using new supported nickel catalysts (Ni/AlPO₄, Ni/AlPO₄–Al₂O₃ and Ni/AlPO₄–SiO₂) in methanol as solvent under low hydrogen pressure (4.1 bar) and 298 K. The kinetic orders are zero in H₂ and aldehyde. The selectivity to the hydrogenaton of the C=C double bond is very high (>99%)

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- (Ni/AlPO₄, Ni/AlPO₄–Al₂O₃ Ni/AlPO₄–SiO₂) (4,1 ) 298 . H₂ . C–C (>90%).

     

Non-catalyzed oscillation reaction in aniline-KBrO3?H2SO4 system, I. Potentiometric study of oscillations

The non-catalyzed oscillation reaction of the aniline-KBrO₃–H₂SO₄ system has been followed potentiometrically. The concentration regions of the beginning of oscillation are given in a triangular diagram. Also studied was the dependence of the induction period on concentration of the participants, which was described by a kinetic equation. The oscillation region extends to lower KBrO₃ concentrations, the number of the oscillation jumps increases, and the induction period is shortened with increasing acidity.

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-KBrO₃–H₂SO₄. . . KBrO₃, .

     

Hydrogenation of CO2

The hydrogenation of CO₂ has been studied on three different series of catalysts: Fe/MgO, Ni/Ti, Cr/Zn doped with potassium. Reaction was carried out in a conventional flow microreactor system at 15 bar at 250–350°C. Three independent competing reactions: Reverse gas-water shift (RGWS), Fischer-Tropsch (FT) and methanol synthesis were observed.

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CO₂ : Fe/MgO, Ni/Ti, Cr/Zn . 15 250–350°C. : RGWS, F.T. .

     

Comparison of the sulfurization of CoMoK/Al2O3 catalyst with H2S and CS2

Only H₂S consumption and H₂O formation was found in the sulfurization of CoMoK/Al₂O₃ water gas shift catalyst with H₂S/H₂, but CO₂ was formed first, then CH₄, H₂O and H₂S appeared in the later part of TPS with CS₂/H₂. Carbon deposition on the catalyst during the sulfurization with CS₂/H₂ caused a lower activity than the catalyst sulfurized with H₂S but could be removed in the run of WGS reaction.

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, CoMoK/Al₂O₃, H₂S/H₂ H₂S H₂O, CS₂/H₂ CO₂ CH₄, H₂O H₂S. CS₂/H₂ H₂S, , .

     

Stereoselectivity observed in cross metathesis of cis- and trans-2-butene with 1-butene over Re2O7/Al2O3 catalyst

Cross metathesis of cis- and trans-2-butene with 1-butene was studied over Re₂O₇/Al₂O₃ catalyst in a recirculation system at 313 K. Formation of ethylene and hexenes was inhibited by 2-butenes; formation of propene and pentene proceeded without induction from trans- and with induction from cis-2-butene and 1-butene. Selective formation of trans-2-pentene was observed from trans-2-butene, but no such selectivity was characteristic for cis-isomers.

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- -2- 1- Re₂O₇/Al₂O₃ 313 . 2-; - -2- 1-. -2 -2-, , - .

     

Effect of rare earth ions on the catalytic activity of Ln2MnNiO6 perovskites

Abstract A series of rare earth transition metal perovskites has been synthesized and the catalytic activity tested for 2-propanol decomposition. The effect of rare earth ions on the catalytic activity can been understood from the correlations obtained between the physico-chemical properties and the catalytic activity of the perovskites.

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, , 2-. , - .

     

Lattice oxygen removal from V6O13 by the TPD method

Removal of the lattice oxygen from the V₆O₁₃ phase has been measured and the activation energy determined.

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V₆O₁₃ .