Temperature-programmed reduction of CuO?NiO/Al2O3 catalysts

Reducibility of NiO/Al₂O₃ and CuO–NiO/Al₂O₃ catalysts has been studied by the TPR method within the temperature range 293–873 K. The results suggest that the copper content essentially does not influence the reducibility of NiO/Al₂O₃.

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NiO/Al₂O₃ CuO–NiO/Al₂O₃ TPR 293–873 . , NiO/Al₂O₃.

     

Benzyl chloride transformation as a probe for electron transfer on Rh/TiO2 under SMSI state

Benzyl chloride transformation has been studied over Rh/TiO₂ under SMSI state to give evidence for the transfer of electrons from support to metal.

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Rh/TiO₂, . .

     

Investigation of ethylene interaction with some oxidants in the presence of Pd2+ in acetic acid

The composition of products from the interaction of ethylene with some o oxidants, catalyzed by palladium acetate in acetic acid has been studied, An assumption is made on the possible reason for the influence of such oxidants on the selectivity of formation of ethylene glycol ethers.

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, , . .

     

Mechanism of methane photooxidation on V/SiO2 catalyst

CH₄ photooxidation on V/SiO₂ catalyst in the presence of gaseous oxygen has been studied by the mass-spectometric method. It has been established that CO₂ forms due to the interaction of CH₄ with surface oxygen anions bonded to vanadium ions. Photodecomposition of V⁴⁺O ₂ ^– species formed in O₂ adsorption on reduced vanadium ions leads to the reoxidation of the latter.

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- CH₄ V/SiO₂ . , CO₂ CH₄ , . V⁴⁺O ₂ ^– O₂ , .

     

1H,13C and17O NMR studies of cumene hydroperoxide coordination to Cr(AA)3

It has been established that the outer sphere coordination of cumene hydroperoxide to Cr(AA)₃ is due to both the formation of hydrogen bonds between hydroxyl proton and chelate oxygen atoms and the --interactions between the aromatic ring and chelate -system.

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, - Cr(III) , --- - .

     

Hexene-1 isomerization catalyzed by the Pd(acac)2?BF3OEt2 system

The data of IR and UV spectroscopic studies of the interaction of Pd(acac)₂+BF₃OEt₂ in the presence of hexene-1 suggest the formation of a Pd–C bond through³C of the acetylacetonate ligand. In the first step of isomerization hexene-1 converts largely (94.5%) to hexene-2.

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- Pd(acac)₂+BF₃OEt₂ -1 , Pd–C ³C- ; , -1 -2, , 94,5%.

     

Reactivity of coordinated O2? ion-radicals in the oxidation of organic compounds

By the flow ESR method, the rates of the reaction of the radical complex Ti(IV)(O ₂ ^– ) with some aromatic compounds in aqueous solution have been measured. An elementary step of these reactions seems to be one-electron oxidation with the formation of a substrate cation-radical.

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- Ti(IV)(O ₂ ^– ) . - -.

     

Catalytic hydrogenation of carbon monoxide on RuFe/SiO2 catalysts

The H₂+CO reaction on silica supported Ru, Fe and RuFe catalysts prepared from metal carbonyl clusters has been investigated under atmospheric and 20 bar pressure. According to the change of selectivity values with temperature and with pressure, the participation of surface carbon proposed earlier by several authors seems to be confirmed by this work.

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H₂+CO Ru, Fe RuFe, , 20 . , , , .

     

ESR study of SO2 on MnO2-alumina

SO ₃ ^– radicals are formed during the reaction between SO₂ and MnO₂-alumina, which suggests that SO ₃ ^– take part in the reduction of Mn⁴⁺ to Mn²⁺.

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SO₂ MnO₂/Al₂O₃ SO ₃ ^– , , SO ₃ ^– Mn⁴⁺ Mn²⁺.

     

A new BPO4 catalyst in organic reactions. Dehydration of cycloalkanols

The synthesis of some new and economical BPO₄ catalysts is described. The chemical and textural properties and the thermogravimetric analysis (TGA) of these catalysts is given. The dehydration of cyclohexanol, cycloheptanol and cyclooctanol catalyzed by these new BPO₄ catalysts is studied using the microcatalytic pulse technique.

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BPO₄. , (). , , BPO₄, .

     

Cyclohexene skeletal isomerization on AlPO4 catalysts precipitated with ammonia and promoted with sulfate ions

This study concerns the effect of SO ₄ ^2– (1–10 wt.%) on the surface acid properties of AlPO₄ catalysts obtained in aqueous ammonia and based on their catalytic activity in cyclohexene skeletal isomerization (CSI) by using the Bassett-Habgood equation for first order processes. It has been found that AlPO₄–SO ₄ ^2– catalysts are much more active in the isomerization process than AlPO₄ catalysts, indicating a strongly increased acidity. Maximum catalytic activity was reached at about 2–3 wt.% and varied with further temperature treatment. Furthermore, the sulfate loading brought about a very pronounced increase in crystallinity even at the smallest content.

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SO ₄ ^2– (1–10 .%) AlPO₄, . , - . , AlPO₄–SO ₄ ^2– , AlPO₄, . 2–3 . % . , .

     

Catalytic mechanism of the reaction between N(4S) nitrogen atoms and sodium azide

Catalytic effect of transition metal oxides on the reaction of monatomic nitrogen with sodium azide has been experimentally established. The maximum effect is exerted by metal oxides with d³ configuration. Absorption of nitrogen atoms by reactive mixtures is accompanied by the complete compensation for the spins of unpaired d-electrons. A catalytic mechanism accounting for the formation of intermediate between d-metal ion and nitrogen atom is suggested.

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. —d³. d-. , d- .

     

Infrared spectra of nitric oxide adsorbed on photoreduced V/SiO2 catalyst

Studies of the IR spectra of surface species produced via NO adsorption on selectively photoreduced V/SiO₂ catalysts indicate that at low coverages NO is adsorbed on V³⁺ ions to form strongly bonded mononitrosyl species V³⁺...... NO. With increasing NO coverage, V³⁺ is oxidized to V⁴⁺, which is accompanied by the appearance of gaseous N₂O and weak adsorption of NO on V⁴⁺.

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- , NO V/SiO₂ . , V³⁺ NO V³⁺... NO. V³⁺ V⁴⁺, N₂O NO V⁴⁺.

     

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 ) .

     

Kinetics of tritium isotope exchange between H2S and CH3OH vapor in glass vessels

Two different mechanisms of tritium exchange between and CH₃OH vapor in glass vessels have been found: (i) bimolecular exchange in the gas phase, (ii) pseudomonomolecular exchange between gaseous and CH₃OH adsorbed on the surface. The total and partial orders, rate constants and activation energies are given.

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, CH₃OH , : 1) 2) CH₃OH, . , .

     

IR spectra of NO and NO+CO mixtures adsorbed on Fe2O3

The interaction of NO and NO+CO mixtures with Fe₂O₃ has been studied by IR spectroscopy. The conclusion has been made that adsorption bands in the region of 1200–1700 cm^–1 belong to nitrite-nitrate structures, the band at 1810 cm^–1 characterizes catalytically active particles of NO adsorbed on reduced surface sites, Fe²⁺, the bands at 2210 and 2240 cm^–1 are due to vibrations of gaseous N₂O.

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- NO NO+CO Fe₂O₃. , 1200–1700 ^–1 - ; 1810 ^–1 NO, , Fe²⁺; 2210 2240 ^–1 N₂O.

     

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.

     

Infrared studies of CO2(CO)8 adsorption on zeolites Y

Co₂(CO)₈ sublimed onto the surface of HY, CeY, CoY and two dealuminated forms of NaY zeolite is converted at room temperature to Co₄(CO)₁₂ and other surfacebound cobalt carbonyl species. The reaction proceeds in a different way on each of the above zeolites, depending also on their pretreatment.

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Co₂(CO)₈, HY, CeY, CoY NaY, Co₄(CO)₁₂ - . - .

     

On the deactivation of Fe2O3?MoO3/SiO2 catalysts in the oxidation of methanol to formaldehyde

The deactivation behavior of Fe₂O₃–MoO₃/SiO₂ catalysts with different Fe₂O₃+MoO₃ content in the oxidation of methanol to formaldehyde is investigated. A simplified reaction-deactivation kinetic model is presented and used to compare and discuss the different behaviors.

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Fe₂O₃–MoO₃/SiO₂ Fe₂O₃+MoO₃ . : -.

     

Study of the interaction of atomic oxygen and nitrogen with ruthenium by the bond interaction method

The heats of atomically adsorbed oxygen and nitrogen on Ru(0001) and Ru(1010) planes have been calculated by the semiempirical bond interaction method. The calculations show that oxygen is strongly adsorbed on ruthenium, while molecular nitrogen cannot be chemisorbed on ruthenium.

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- (000I) (I0I0) . , Ru , .