Oxygen Spillover in the Conversion of NO on a Pd-Co/γ-Al2O3 Catalyst

Oxygen spillover was detected in the decomposition of NO on a Pd-Co/-Al₂O₃ catalyst obtained by the thermolysis of [Co(NH₃)₅Cl][PdCl₄].     

KF/Al2O3-Mediated Michael Addition of Thiols to Electron‐Deficient Olefins

Potassium fluoride supported on alumina efficiently catalyzes Michael addition of aromatic and aliphatic thiols to a variety of conjugated alkenes such as α,β‐unsaturated carbonyl compounds, carboxylic esters, amides, nitriles and chalcones. The Michael adducts are produced in good to excellent yields and relatively in short times. The catalyst can be recycled for subsequent reactions without any appreciable loss of efficiency.     

Structural Properties of Ni/γ−Al2O3 and Cu/γ−Al2O3 Catalyst and its Application for Hydrogenation of Furfurylidene Acetone

Hydrogenation of furfurylidene acetone has been carried out using Ni/γ−Al₂O₃ and Cu/γ−Al₂O₃ catalyst in the presence of isopropanol in autoclave batch reactor. The hydrogenation using Cu/γ−Al₂O₃ at 120^oC for 6 h gives main formation of 1,5-bis-(furan-2-yl)-pentan-3-one. Reaction at higher temperature at 140^oC for 8 h using Ni/γ−Al₂O₃ leads to 1,5-bis-(furan-2-yl)-penta-1-en-3-one. The different selectivity of both catalysts is explained by physical properties including the surface area and distribution of metal loading.     

Study of CO2 Hydrogenation to Methanol over Cu-V/γ-Al2O3 Catalyst

The effect of vanadium addition to CU/γ-Al2O3 catalyst used in the hydrogenation of CO2 to produce methanol was studied. It was found that the catalytic performance of the Cu-based catalyst improved after V addition. The influence of reaction temperature, space velocity and the molar ratio of H2 to CO2 on the performance of 12%Cu-6%V/γ-Al2O3 catalyst were also studied. The results indicated that the best conditions for reaction were as follows: 240℃, 3600 h-1 and a molar ratio of H2 to CO2 of 3:1. The results of XRD and TPR characterization demonstrated that the addition of V enhanced the dispersion of the supported CuO species, which resulted in the enhanced catalytic performance of CU-V/γ-Al2O3 binary catalyst.     

Adsorption of Chlorobenzene on V2O5/γ-Al2O3 Catalyst

Isotherms of chlorobenzene adsorption on V₂O₅/-Al₂O₃ catalyst within the 0.07-18 Pa range of adsorbate partial pressure were measured, and certain thermodynamic characteristics of adsorption were found.     

High Activity SnO2／Al2O3 Catalyst for NO Reduction in the Presence of Oxygen

The novel sol-gel SnO2/Al2O3 catalysts for selective catalytic reduction NO by propene under lean burn condition were investigated. The results showed thatthe maximum NO conversion was 82% on the SnO2/Al2O3 (5%Sn) catalyst, and the presence of H20 and SO2 improved the catalytic activity at low temperature. The catalytic activity of NO2 reduction by propene is much higher than that of NO at the entire temperature range, and the maximum NO2 conversion reached nearly 100% around the temperature 425℃.     

Application of Fe2O3/Al2O3 Composite Particles as Oxygen Carrier of Chemical Looping Combustion

Chemical looping combustion (CLC) of carbonaceous compounds has been proposed, in the past decade, as an efficient method for CO2 capture without cost of extra energy penalties. The technique involves the use of a metal oxide as an oxygen carrier that transfers oxygen from combustion air to fuels. The combustion is carried out in a two-step process: in the fuel reactor, the fuel is oxidized by a metal oxide, and in the air reactor, the reduced metal is oxidized back to the original phase. The use of iron oxide as an oxygen carrier has been investigated in this article. Particles composed of 80 wt% Fe2O3, together with Al2O3 as binder, have been prepared by impregnation methods. X-ray diffraction (XRD) analysis reveals that Fe2O3 does not interact with the Al2O3 binder after multi-cycles. The reactivity of the oxygen carrier particles has been studied in twenty-cycle reduction-oxidation tests in a thermal gravimetrical analysis (TGA) reactor. The components in the outlet gas have been analyzed. It has been observed that about 85% of CH4 converted to CO2 and H2O during most of the reduction periods. The oxygen carrier has kept quite a high reactivity in the twenty-cycle reactions. In the first twenty reaction cycles, the reaction rates became slightly higher with the number of cyclic reactions increasing, which was confirmed by the scanning electron microscopy (SEM) test results. The SEM analysis revealed that the pore size inside the particle had been enlarged by the thermal stress during the reaction, which was favorable for diffusion of the gaseous reactants into the particles. The experimental results suggested that the Fe2O3/Al2O3 oxygen carrier was a promising candidate for a CLC system.     

Water/Oil Diphasic Hydroformylation of Higher Olefins over a TPPTS-Rh/SiO_2 Catalyst

A novel TPPTS-Rh/SiO2 catalyst, prepared by directly modifying a heterogeneous high-surface-area Rh/SiO2 catalyst with water-soluble TPPTS ligands, could decrease the resistance of mass transfer in water/oil biphasic media for the hydroformylation of higher olefins. The catalytic performance for hydroformylation on this biphasic TPPTS-Rh/SiO2 catalyst system was higher than those of the traditional biphasic HRhCO(TPPTS)3 systems, owing to the chemical bonds between the highly dispersed Rh metal particles and the TPPTS ligands. The catalyst system is applicable for hydroformylation of higher olefins such as 1-dodecene.     

Mild and Efficient Michael Addition of Activated Olefins to Indoles using TBAB as a Catalyst: Synthesis of 3‐Substituted Indoles

A mild and efficient method for the synthesis of 3‐substituted indoles by treatment of activated olefins with indoles using TBAB as a catalyst afforded the corresponding products in excellent yields. The method is general for the preparation of a wide variety of 3‐substituted indoles.     

Kinetics of Methane Partial Oxidation to Syngas over a LiLaNiO/γ -Al2O3 Catalyst

The kinetic behavior of partial oxidation of methane to syngas over a LiLaNiO/γ -Al₂O₃ catalyst was investigated under steady-state conditions. Under kinetic control, syngas, to a large extent, is formed via a direct partial oxidation (DPO) scheme. CO and CO₂ are formed in parallel by oxidation reaction over the catalyst. The active sites in the kinetically controlled regime are different from those in the non-kinetic regime, thus the CO selectivity in the former may not increase with temperature. This revised version was published online in June 2006 with corrections to the Cover Date.     

Cofeeding of Methane and Ethane to Produce Syngas over a LiLaNiO/γ-Al_2O_3 Catalyst

There are abundant supplies of mixture gases containing CH, and C,H, from natural gas,FCC (Fluidized Catalytic Cracking) dry gas, refinery gas, elc. Commonly, the amount ofC,H, is relatively lower than that of CH,. With regard to the utilization of methane,partial oxidation of methane to syngas over nickel based catalysts has received intensiveallention l'2. For mixture gases containing CH# and C,H,, their conversion to syngas isalso of significance (but has not gained adequate attentio…     

Effect of La2O3／γ—Al2O3 Catalyst on the Activation of CH4 and CO2 to C2 Hydrocarbons under Non—equilibrium Plasma

In the reaction of methane and carbon dioxide to C2 hydrocabons under non-equilibrium plasma, methane conversion was decreased,but selectivity of C2 hydroxarbons was increased when using La2O3/γ-Al2O3 as catalyst. So the yield of C2 hydrocarbons was higher than using plasma alone. The synergism of La2O3/γ-Al2O3 and plasma gave methane conversion of 24.9% and C2 yield of 18.1%. The distribution of C2 hydrocarbons changed when Pd-La2O3/γ-Al2O3 was used as catalyst,the major C2 product was ethylene.     

Catalytic Conversion of Glycerol in the Presence of Ni/F–Al2O3 Catalyst

Russian Journal of Physical Chemistry A - It is shown that glycerol hydrogenation in the presence of Ni/F–Al2O3 catalyst leads to the formation of simple alcohols ethanol and propanol-1. The...     

Methane Coupling Using Hydrogen Plasma and Pt／γ—Al2O3 Catalyst

In this paper,methane coupling at ambient temperature, under atmospheric pressure and in the presence of hydrogen was firstly investigated by using pulse corona plasma and Pt/γ-Al2O3 catalyst. Experimental results showed that Pt/γ-Al2O3 catalyst has catalytic activity for methane couplin to C2H4. Over sixty percent o outcomes of C2 hydrocarbons were detected to be ethylene.     

Enhancement of Activity of SnO2-doped In2O3/Al2O3 Catalyst for NO Reduction with Propene in the Presence of H2O and SO2

The selective catalytic reduction of nitrogen oxides by hydrocarbons (HC-SCR) has attracted much attention as an efficient way to remove NO in the presence of excess oxygen1-2. The metal oxides are the most promising catalysts for the SCR of NO because of their high activity and selectivity3-5. In the previous work, the metal oxides such as Ag, Sn, In, Co supported on alumina for NO reduction were investigated6-8, however, the HC-SCR is usually suppressed in the presence of H2O and S…     

Kinetics of the Oxidative Dehydrogenation of Isobutane over Cr_2O_3/La_2(CO_3)_3

The oxidative dehydrogenation (ODH) of isobutane over Cr2O3/La2(CO3)3 has been investigated in a low-pressure Knudsen cell reactor, under conditions where the kinetics of the primary reaction steps can be accurately determined. By heating the catalyst at a constant rate from 150-300℃, temperature fluctuations due to non-equilibrium adsorption are minimized. The evolved gas profiles show that ODH to isobutene and water is a primary reaction pathway, while carbon dioxide, which forms from the catalyst during reaction, is the only other product. This CO2 evolution may enhance the activity of the catalyst. Isobutene formation proceeds with the participation of lattice oxygen from the Cr2O3/La2(CO3)3 catalyst. The intrinsic Arrhenius rate constant for the ODH of isobutane isk(s-1) = 1011.5±2.2exp{-((55±5) -ΔHads kJmol-1)/RT}The small pre-exponential factor is expected for a concerted mechanism and for such a catalyst with a small surface area and limited porosity.     

Kinetics of the Thermal Desorption of Atomic Oxygen during Transformations BiO2 – x→ β-Bi2O3→ α-Bi2O3

The thermal desorption of atomic oxygen during the transformations BiO_{2 – x} -Bi₂O₃ -Bi₂O₃is shown to be due to the removal of overstoichiometric oxygen from the bulk of -Bi₂O₃. Oxygen formed at the first stage is desorbed in a molecular form. The maximum desorption rate of atomic oxygen is found before the phase transformation -Bi₂O₃ -Bi₂O₃. The activation energy of the diffusion of excess oxygen in the -Bi₂O₃lattice is 30 kcal/mol.     

Direct Synthesis of Acetic Acid from CH4 and CO2 in the Presence of O2 over a V2O5-PdCl2／Al2O3 Catalyst

The possibility of synthesizing acetic acid from CH4 and CO2 in the presence of O2 over a V2O5-PdCl2/Al2O3 catalyst has been explored. The result shows that it is feasible in catalyzing a direct conversion of CH4, CO2 and O2 to acetic acid. It is concluded that both CO2 and O2 are involved in the formation of acetic acid.