Treatment of 5,8-dihydroxy-1-tetralone (9) with either 2,3-dichloro-5,6- dicyano-1,4-benzoquinone (DDQ) in refluxing benzene or silver (I) oxide in refluxing 1,4-dioxane afforded juglone (5-hydroxy-1,4-naphthoquinone) (1) in good yield. With manganese dioxide in dioxane the tetralone gave a mixture of juglone and naphthazarin (5,8-dihydroxy-1,4-naphthoquinone) (3), the proportion of naphthazarin being increased by the presence of water. Silver (I) oxide in 1,4- dioxane converted 9,10-dihydroxy-1-oxo (14),9,10-dihydroxy-1,5-dioxo (15), and 1,8-dioxo-1,2,3,4,5,6,7,8-octahydro anthracene (16) into, respectively, 1-hydroxy- 5,6,7,8-tetrahydro (23), 1,5-dihydroxy (6), and 1,8-dihydroxy-9,10-anthraquinone (4), in high yield. Mechanisms for these transformations are discussed.

The molecularly dispersed BiP1-xVxO4/TiO2 supported materials, with x varying from 0 to 1, were prepared by impregnation of Bismuth, Phosphorus, and Vanadium on a Titanium Oxide TiO2 support. Their structures were characterized by different techniques including X-ray diffraction, Spectroscopic Raman, temperature-programmed reduction of the catalysts in H2 (H2-TPR), and by the methanol oxidation reaction. This very sensitive technique provided us with relevant information on the nature of the catalytic active sites (acid-base and redox) of the phases dispersed on the support. The characterization results show the structural evolution of BiP1-xVxO4 species, from isolated BiPO4 crystallites for x =0, to BiVO4 crystallites x =1. The oxidation of methanol showed the acidic properties of the BiPO4/TiO2 catalyst, through the formation of dimethyl ether as the major product of the reaction. The substitution of phosphorus by vanadium promotes the formation of formaldehyde, confirming the presence of redox sites. These catalysts were examined in the OXIDATIVE dehydrogenation (ODH) of propane to propene. For x > 0. 5, dispersed BiVO4 exhibited higher levels of propane ODH than BiPO4 crystallites, consistent with their greater reducibility probed by temperature-programmed reduction of H2 and the presence of redox sites confirmed by methanol oxidation, with good selectivity to propene. Catalysts with x = 0, were less selective to propene due to favorable propylene combustion during its formation. A thorough understanding of the intrinsic catalytic properties of the BiP1-xVxO4/TiO2 oxides and in particular the BiPO4 and BiVO4 crystallites provides relevant information on the structural requirements of the propane ODH reaction, of interest for the design of more efficient Bi-P-V-O based catalysts for propene production. The results show that all substituted catalysts exhibit significant propene selectivity. In addition, the BiP0. 7V0. 3O4/TiO2 catalyst exhibits high activity with good propene selectivity. This catalytic activity was correlated with high reducibility.

The molecularly dispersed BiP1-xVxO4/SiO2 supported oxides, with x varying from 0 to 1, were prepared by impregnation of Bismuth, Phosphorus, and Vanadium on silica. Their structures have been characterized by different techniques: X-ray diffraction, Raman spectroscopy, Temperature-Programmed Reduction of catalysts in H2 (H2-TPR), and methanol oxidation reaction. This very sensitive technique provided us with relevant information on the nature of the active sites (acid-base and redox) on the surface of the catalysts. The results of the characterization show the structural evolution of the vanadium species of the isolated crystallites from V2O5 for x =0.3 and x =0.5, to BiVO4, with the disappearance of BiPO4, with the increase of the vanadium content from x=0.5 to x = 1. The oxidation of methanol showed the basic properties of the BiPO4/SiO2 catalyst, by the formation of carbon dioxide as the major product of the reaction. The substitution of phosphorus with vanadium promotes the formation of formaldehyde, confirming the presence of redox sites on these substituted catalysts. These catalysts were examined in the OXIDATIVE dehydrogenation (ODH) of propane. For x ≥ 0.5, the dispersed BiVO4 exhibited significant activity in propane ODH than the BiPO4 and V2O5 crystallites, with good selectivity to propylene and acrolein, consistent with their high reducibility confirmed by H2-TPR, and the presence of redox sites shown by the oxidation of methanol. The catalyst with x = 0 was less selective for propylene due to the favorable combustion of propylene during its formation. Such an understanding of the intrinsic catalytic properties of the BiP1-xVxO4/SiO2 oxides and in particular, the BiPO4 and BiVO4 crystallites provides new information on the structural requirements of the propane ODH reaction, beneficial for the design of more efficient Bi-P-V-O based catalysts for propylene and acrolein production.

In this study, characterization of vanadia supported on Al-modified titania nanotubes (TiNTs) synthesized by the alkaline hydrothermal treatment of TiO2 powders has been reported. A promising catalyst for OXIDATIVE dehydrogenation (ODH) of propane was prepared via the incipient wetness impregnation method. The morphology and crystalline structure of TiNTs were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). TiNTs provided large specific surface areas of about 408 m2/gr and 1.603 cm3/gr for pore volume. Rapid sintering and anatase to rutile phase transformation occurred in presence of vanadia in the catalysts at high calcination temperature. Al-promoted TiNTs considerably inhibited the loss of surface area so that a superior catalytic activity was observed in the ODH of propane along with amelioration of structural properties. The results showed 49.7% increase in propane conversion and 22.6% increase in propylene production at 500οC for Al-modified catalyst.

Supported vanadia catalyst was successfully synthesized using wet impregnation of g-alumina to study Propane OXIDATIVE Dehydrogenation (POD). The prepared catalysts were characterized with XRD, BET, and TPR tests. In a broad temperature range (340oC to 630oC), effects of vanadia loading (2.7, 5.4, and 9 wt%) and propane to oxygen ratio (3/1 to 1/3) were investigated on propane conversion as well as propene yield at atmospheric pressure. Results indicate that by increasing the vanadia content the activity of catalyst increases while selectivity to propene decreases monotonically. As the temperature increases from 340oC to 630oC, yield to propene shows ascending behavior in case of all catalyst samples. Yield to propene shows a climax with changing propane to oxygen ratio from 3/1 to 1/3. The yield increases with increase in oxygen partial pressure of feed until equimolar ratio of propane and oxygen, then it declines with further increase of oxygen partial pressure. Higher propene yields were observed at higher temperatures and equimolar feed ratio of propane and oxygen (C3/O2=1/1). A maximum propene yield of 17% was experienced on catalyst with 2.7 wt% vanadia at temperatures at 550oC.

In this study at first, in laboratory, three types of vanadium oxide were produced by using porous graphene and amine framework in hydrothermal method nanostructures such as: vanadium oxide-octadecyl amine- graphene, vanadium oxide-dodecyl amine-graphene and vanadium oxide – aniline-graphene (V-ODA-G، V-DDA-G، V-A-G). Then their structures and functions in propane dehydrogenation reactions were studied and productivity and efficiency of these catalysts in mentioned reactions were compared with each other. In order to notice and compare the structures and properties of synthesized catalysts, some methods such as Field Emission Scanning Electron Microscope (FE-SEM), X Ray Diffraction (XRD), Thermo Gravimetric Analysis (TGA), Fourier Transform Infrared Spectrometry (FTIR), Gas Chromatography (GC) have been used. The obtained results show that vanadium oxide nanostructures have great opportunities to be OXIDATIVEly dehydrogenation (ODH) and make sciences explore the use of porous grapheme as catalysts for propane OXIDATIVE dehydrogenation.