The invention relates to a catalyst which comprises: a) a mixed metal oxide of molybdenum, vanadium, niobium and in optionally tellurium; and b) ceria particles having a crystallite size greater than 15 nanometers (nm); wherein the amount of the ceria particles, based on the total amount of the catalyst, is of from 1 to 60 wt. %. Further, the invention relates to a process for preparing a catalyst, which comprises mixing a mixed metal oxide of molybdenum, vanadium, niobium and optionally tellurium with ceria particles having a crystallite size greater than 15 nanometers (nm), wherein the amount of the ceria particles, based on the total amount of the catalyst, is of from 1 to 60 wt. %. Still further, the invention relates to an alkane oxidative dehydrogenation and/or alkene oxidation process wherein such catalyst is used.

Present subject matter provides a semiconductor nanocrystal comprises a core and a shell. The core is fabricated from a first semiconductor. The shell is fabricated from a second semiconductor. The optical cross section of the semiconductor nanocrystal is in a range of 10.sup.−17 cm.sup.2-10.sup.−12 cm.sup.2 in a 2-3 eV region. The core is less than 2 nanometers from an outer surface of the shell in at least one region of the semiconductor nanocrystal. Present subject matter also provides method for preparation of the semiconductor nanocrystals and method for photosynthesis of organic compounds.

Oxidative dehydrogenation catalysts for converting lower paraffins to alkenes such as ethane to ethylene when prepared as an agglomeration, for example extruded with supports comprising slurries of Nb.sub.2O.sub.5.

The invention relates to a process for the production of ethylene by oxidative dehydrogenation (ODH) of ethane, comprising: a) supplying ethane and oxygen to a first ODH zone which is formed by multiple reactor tubes containing a mixed metal oxide ODH catalyst bed; b) contacting the ethane and oxygen with the catalyst resulting in multiple effluent streams, wherein the multiple reactor tubes are cooled by a coolant; c) mixing at least a portion of the multiple effluent streams from step b) resulting in a mixture comprising ethylene, unconverted ethane and unconverted oxygen; d) supplying at least a portion of the mixture from step c) to a second ODH zone containing a mixed metal oxide ODH catalyst bed; e) contacting at least a portion of the mixture from step c) with the catalyst in the second ODH zone resulting in a stream comprising ethylene and unconverted ethane.

Provided in this disclosure are catalyst compositions. The catalyst compositions include an oxidative dehydrogenation catalyst that includes a mixed metal oxide having the empirical formula:

Mo.sub.1.0V.sub.0.12-0.49Te.sub.0.05-0.17Nb.sub.0.10-0.20Al.sub.cO.sub.d

wherein c is from 0 to 2.0 and d is a number to satisfy the valence of the oxide. The compositions are at least 40 wt. % amorphous as measured by XRD. The disclosure also provides methods of making the compositions.

The invention relates to a process for preparing a catalyst for alkane oxidative dehydrogenation and/or alkene oxidation, which catalyst is a mixed metal oxide catalyst containing molybdenum, vanadium, niobium and optionally tellurium, wherein the process comprises: a) preparing a catalyst precursor containing molybdenum, vanadium, niobium and optionally tellurium; b) optionally contacting the catalyst precursor obtained in step a) with oxygen and/or an inert gas at an elevated temperature; c) contacting the catalyst precursor obtained in step a) or step b) with a gas mixture comprising ammonia and water, which gas mixture further comprises oxygen and/or an inert gas, at an elevated temperature; and d) optionally contacting the catalyst precursor obtained in step c) with an inert gas at an elevated temperature. Further, the invention relates to a catalyst obtainable by said process and to a process of the oxidative dehydrogenation of an alkane containing 2 to 6 carbon atoms and/or the oxidation of an alkene containing 2 to 6 carbon atoms wherein said catalyst is used.

Mixed metal oxide catalysts having an amorphous content of not less than 40 wt. % are prepared by calcining the catalyst precursor fully or partially enclosed by a porous material having a melting temperature greater than 600° C. in an inert container including heating the catalyst precursor at a rate from 0.5 to 10° C. per minute from room temperature to a temperature from 370° C. to 540° C. under a stream of pre heated gas chosen from steam and inert gas and mixtures thereof at a pressure of greater than or equal to 1 psig having a temperature from 300° C. to 540° C. and holding the catalyst precursor at that temperature for at least 2 hours and cooling the catalyst precursor to room temperature.

This document relates to oxidative dehydrogenation catalysts that include molybdenum, vanadium, and oxygen.

The reaction rate of hydrocarbon pyrolysis can be increased to produce solid carbon and hydrogen by the use of molten materials which have catalytic functionality to increase the rate of reaction and physical properties that facilitate the formation and contamination-free separation of the solid carbon. Processes, materials, reactor configurations, and conditions are disclosed whereby methane and other hydrocarbons can be decomposed at high reaction rates into hydrogen gas and carbon products without any carbon oxides in a single reaction step. The process also makes use of specific properties of selected materials with unique solubilities and/or wettability of products into (and/or by) the molten phase to facilitate generation of purified products and increased conversion in more general reactions.

A chemical complex to perform oxidative dehydrogenation of C2-C4 alkanes, to C2-C4 alkenes, the chemical complex involving at least one oxidative dehydrogenation reactor containing one or more mixed metal oxide catalysts and designed to accept, optionally in the presence of a heat removal diluent gas, an oxygen containing gas and a C2-C4 alkane containing gas, and to produce a product stream including a corresponding C2-C4 alkene and one or more of: an unreacted C2-C4 alkane; oxygen; heat removal diluent gas; carbon oxides, including carbon dioxide and carbon monoxide; oxygenates, including but not limited to, one or more of acetic acid, acrylic acid and maleic acid; and water; and involving a combustion chamber for combusting a product stream and at least one fuel stream and optionally at least one stream including oxygen, the combustion chamber producing a flue gas at a temperature of 850° C. to 1500° C.