Ethylbenzene into styrene with carbon dioxide over modified vanadia–alumina catalysts

The effect of addition of antimony oxide and/or sodium nitrate to silicate glass compositions upon the changes in the relative concentrations of oxygen and carbon dioxide in their bubbles from heat treatment was investigated using the Raman microprobe technique. The addition of antimony oxide to these glasses increased the relative rates of oxygen dissolution from their bubbles with respect to glasses containing no refining agents. These increases were closely related to the absolute amounts of Sb3+ ions that were present in the glasses. The relative rates were faster for glasses containing antimony oxide than for glasses containing the same molar amounts of arsenic oxide. The higher Sb3+/Sb5+ ratios for glasses containing antimony oxide with respect to the As3+/As5+ ratios for glasses containing arsenic oxide caused the relative rates of oxygen dissolution to be dramatically greater for the former glasses. In contrast to an earlier investigation with silicate glasses containing arsenic oxide, the addition of sodium nitrate to glasses containing antimony oxide using a similar glass preparation did not significantly change their relative rates of oxygen dissolution.

Utilization of carbon dioxide as a soft oxidant for the catalytic dehydrogenation of ethylbenzene (CO2-EBDH) has been recently attempted to explore a new technology for producing styrene selectively. This article summarizes the results of our recent attempts to develop effective catalyst systems for the CO2-EBDH on the basis of alumina-supported vanadium oxide catalysts. Its initial activity and on-stream stability were essentially improved by the introduction of antimony oxide as a promoter into the alumina-supported catalyst. Insertion of zirconium oxide into alumina support substantially increased the catalytic activity. Modification of alumina with magnesium oxide yielded an increase of catalyst stability of alumina-supported V–Sb oxide due to the coking suppression. Carbon dioxide has been confirmed to play a beneficial role of selective oxidant in improving the catalytic performance through the oxidative pathway, avoiding excessive reduction and maintaining desirable oxidation state of vanadium ion (V5+). The positive effect of carbon dioxide in dehydrogenation reactions of several alkylbenzenes such as 4-diethylbenzene, 4-ethyltoluene, and iso- and n-propylbenzenes was also observed. Along with the easier redox cycle between fully oxidized and partially reduced vanadium species, the optimal surface acidity of the catalyst is also responsible for achieving high activity and catalyst stability. It is highlighted that supra-equilibrium EBDH conversions were obtained over alumina-supported V–Sb oxide catalyst in CO2-EBDH as compared with those in steam-EBDH in the absence of carbon dioxide.

Liquid fuel synthesis via CO2 hydrogenation by coupling homogeneous and heterogeneous catalysis

This work shows that carbon dioxide, which is a main contributor to the global warming effect, could be utilized as a selective oxidant in the oxidative dehydrogenation of ethylbenzene over alumina-supported vanadium oxide catalysts. The modification of the catalytically active vanadium oxide component with appropriate amounts of antimony oxide led to more stable catalytic performance along with a higher styrene yield (76%) at high styrene selectivity (>95%). The improved catalytic behavior was attributable to the enhanced redox properties of the active V-sites.

This work concerns the synthesis of two types of composites based on antimony oxide named (Sb2O3):(WO3, In2O3). Thin films were fabricated using pulsed laser deposition. The compositional analysis was explored using Fourier transform infrared spectrum (FTIR), which confirms the existence of antimony, tungsten, and indium oxides in the prepared samples. The hall effect measurement showed that antimony oxide nanostructure thin films are p-type and gradually converted to n-type by the addition of tungsten oxide, while they are converted almost instantly to n-type by the addition of indium oxide. Different heterojunction solar cells were prepared from (Sb2O3:WO3, In2O3/Sb2Se3/c-pSi) contained forms from two layers the first was Sb2Se3 and the second was (Sb2O3):(WO3, In2O3) nanostructured thin films. The heterojunction (Sb2O3:15%WO3 Sb2Se3/c-pSi showed a maximum conversion efficiency of 9% and exhibits an open circuit voltage (Voc) of 300 mV, short circuit current (Isc) of 35 mA, and a fill factor of 0.429 at an intensity of illumination of 100 mW/cm2.

Highly efficient synthesis of dimethyl ether from syngas over the admixed catalyst of CuO–ZnO–Al 2O 3 and antimony oxide modified HZSM-5 zeolite

Oxidation of benzothiophene by tert-butyl hydroperoxide over vanadia–alumina catalyst: An FT-IR study at the vapour–solid interface

Promotional effect of sodium and phosphorus on a V-Mo-O catalyst

Quantifying Electrocatalytic Reduction of CO2 on Twin Boundaries

Deactivation and oxidative regeneration of VTiSbSiO catalyst for ammoxidation of 3-picoline to nicotinonitrile

Constructing FeN4/graphitic nitrogen atomic interface for high-efficiency electrochemical CO2 reduction over a broad potential window

Catalytic oxidation of thioanisole Ph–S–CH 3 over VO x/SiO 2 and VO x/Al 2O 3 catalysts prepared by sol–gel method

Oxidative dehydrogenation of ethylbenzene over vanadia-alumina catalysts in the presence of nitrous oxide: structure-activity relationship

The vapour phase oxidation of propylene to acrylic acid is generally carried out by a two step process, involving acrolein as an intermediate. In this work, the kinetic data on the second step of the process, i.e. the oxidation of acrolein to acrylic acid were obtained using a catalyst containing oxides of antimony, nickel and molybdenum. The effects of temperature, space time and concentration of acrolein and oxygen on the yield and conversion to acrylic acid were studied, and the most suitable conditions were determined for the process. Carbon dioxide was the major by product in the reaction. The formation of acrylic acid and carbon dioxide were correlated by suitable rate expressions.

The vapour phase oxidation of propylene to acrylic acid is generally carried out by a two step process, involving acrolein as an intermediate. In this work, the kinetic data on the second step of the process, i.e. the oxidation of acrolein to acrylic acid were obtained using a catalyst containing oxides of antimony, nickel and molybdenum. The effects of temperature, space time and concentration of acrolein and oxygen on the yield and conversion to acrylic acid were studied, and the most suitable conditions were determined for the process. Carbon dioxide was the major by product in the reaction. The formation of acrylic acid and carbon dioxide were correlated by suitable rate expressions.