Methods for oxidative coupling of methane using metal oxide catalysts and a sulfur oxidant.

Process for dehydrogenation of alkanesor alkylbenzenes by using metal sulfide catalyst under the presence of small amounts of hydrogen sulfide.

The invention concerns a method for the photocatalytic reduction of carbon dioxide carried out in the liquid phase and/or in the gas phase under irradiation using a photocatalyst comprising a support made from alumina or silica or silica-alumina and nanoparticles of molybdenum sulfide or tungsten sulfide having a band gap greater than 2.3 eV, said method comprising the following steps: a) bringing a feedstock containing carbon dioxide and at least one sacrificial compound into contact with said photocatalyst, b) irradiating the photocatalyst with at least one source of irradiation producing at least one wavelength smaller than the width of the band gap of said photocatalyst so as to reduce the carbon dioxide and oxidise the sacrificial compound in the presence of said photocatalyst activated by said source of irradiation, in such a way as to produce an effluent containing, at least in part, C1 or above carbon-containing molecules, different from CO2.

The invention concerns a method for the photocatalytic reduction of carbon dioxide carried out in the liquid phase and/or in the gas phase under irradiation using a photocatalyst comprising a support made from alumina or silica or silica-alumina and nanoparticles of molybdenum sulfide or tungsten sulfide having a band gap greater than 2.3 eV, said method comprising the following steps: a) bringing a feedstock containing carbon dioxide and at least one sacrificial compound into contact with said photocatalyst, b) irradiating the photocatalyst with at least one source of irradiation producing at least one wavelength smaller than the width of the band gap of said photocatalyst so as to reduce the carbon dioxide and oxidise the sacrificial compound in the presence of said photocatalyst activated by said source of irradiation, in such a way as to produce an effluent containing, at least in part, C1 or above carbon-containing molecules, different from CO2.

Aspects of the invention are associated with the discovery of approaches for the conversion of sour natural gas streams, by conversion to liquid hydrocarbons. Particular processes and their associated apparatuses advantageously combine (i) dehydroaromatization (DHA) of methane in a gaseous feedstock, to produce aromatic hydrocarbons such as benzene, with (ii) the reaction of H.sub.2S and methane in this feedstock, to produce organic sulfur compounds such as carbon disulfide (CS.sub.2) and thiophene (C.sub.4H.sub.4S). A gaseous product having a reduced concentration of H.sub.2S is thereby generated. The aromatic hydrocarbons and organic sulfur compounds may be recovered in a liquid product. Both the gaseous and liquid products may be easily amenable to further upgrading. Other advantages of the disclosed processes and apparatuses reside in their simplicity, whereby the associated streams, including a potential gaseous recycle, generally avoid high partial pressures of H.sub.2S.

A catalyst for the dehydrogenation of alkanes to alkenes comprises a catalytically active material supported on a carrier, wherein the catalytically active material is a metallic sulfide (MeS) comprising Fe, Co, Ni, Cu, Mo or W or any combination of two or more metals selected from Pb, Sn, Zn, Fe, Co, Ni, Cu, Mo and W. The catalyst is regenerated in several steps. The dehydrogenation is carried out at a temperature between 450 and 650 C. and a pressure from 0.9 bar below ambient pressure to 5 bar above ambient pressure.

The present invention provides a supported metal catalyst with synergistic sites, a preparation method therefor and an application thereof. The preparation method of this catalyst is to utilize the unsaturated cubane-like structure, M cation with catalytic activity is introduced into the cluster core unit. By using the vertex vacancy as the capturing center, and adjusting the impregnation temperature to maximize the loading of the cluster precursor, as well as depending on the electrostatic adsorption of the support and the confinement of the cluster structural unit, the number of S vacancies and the distance between S vacancies and Miso sites are effectively controlled through liquid phase reduction and atmosphere treatment at room temperature to obtain supported X3MSx/Al2O3 catalyst with Miso-Vs synergistic sites. The method of the present invention achieves the joint enhancement of the activity, product selectivity, and stability of unsaturated carbon oxygen bond selective hydrogenation, carbon chlorine bond selective hydrogenation dechlorination, and carbon hydrogen bond dehydrogenation reactions. This catalyst is mainly used in various catalytic reaction processes in the fields of petrochemical, fine chemical, environmental chemical, and other fields. It has outstanding catalytic performance, excellent activity, selectivity, and good recyclability, and is easy to recover and reuse.

Aspects of the invention are associated with the discovery of approaches for the conversion of sour natural gas streams, by conversion to liquid hydrocarbons. Particular processes and their associated apparatuses advantageously combine (i) dehydroaromatization (DHA) of methane in a gaseous feedstock, to produce aromatic hydrocarbons such as benzene, with (ii) the reaction of H.sub.2S and methane in this feedstock, to produce organic sulfur compounds such as carbon disulfide (CS.sub.2) and thiophene (C.sub.4H.sub.4S). A gaseous product having a reduced concentration of H.sub.2S is thereby generated. The aromatic hydrocarbons and organic sulfur compounds may be recovered in a liquid product. Both the gaseous and liquid products may be easily amenable to further upgrading. Other advantages of the disclosed processes and apparatuses reside in their simplicity, whereby the associated streams, including a potential gaseous recycle, generally avoid high partial pressures of H.sub.2S.

Processes for conversion of propylene polyol feed into useful petrochemical products, including olefin monomers, are described. Such processes comprise: adding a feed stream comprising one or more propylene polyols to a dehydration cleavage reaction zone in the presence of a dehydration cleavage catalyst and reacting at a pressure and temperature sufficient to form a product stream comprising propionaldehyde, a dioxolane component, and a dioxane component; and adding the product stream and hydrogen to a dehydration reaction zone in the presence of a hydrogenation catalyst to form and reacting at a pressure and temperature sufficient to form a second product stream comprising a propanol component. The second product can be added to a dehydration reaction zone in the presence of a dehydration catalyst and reacted at a pressure and temperature sufficient to form a third product stream comprising propylene.

The invention relates to a process for the preparation of nanoparticles of MoS.sub.2 supported on TiO.sub.2 wherein the preparation is performed by reductive coprecipitation using aqueous solutions containing Ti and Mo precursor salts, and wherein MoS.sub.2 may be non-promoted or Co-promoted. Further, the invention relates to the use of said nanoparticles as hydrodesulfurization catalysts.