The invention relates to a process for treatment of a mixed metal oxide catalyst containing molybdenum, vanadium, niobium and optionally tellurium, comprising contacting a gas stream comprising methane, an inert gas or oxygen or any combination of two or more of these with the catalyst, wherein said gas stream comprises 0 to 25 vol. % of an alkane containing 2 to 6 carbon atoms and/or alkene containing 2 to 6 carbon atoms.

The invention relates 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, comprising contacting a first gas stream comprising methane, an inert gas or oxygen or any combination of two or more of these, wherein the first gas stream comprises 0 to 2 vol. % of the alkane containing 2 to 6 carbon atoms and/or alkene containing 2 to 6 carbon atoms, with a mixed metal oxide catalyst containing molybdenum, vanadium, niobium and optionally tellurium; followed by contacting a second gas stream comprising oxygen and the alkane containing 2 to 6 carbon atoms and/or the alkene containing 2 to 6 carbon atoms with the catalyst.

The invention relates 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, comprising contacting a first gas stream comprising methane, an inert gas or oxygen or any combination of two or more of these, wherein the first gas stream comprises 0 to 2 vol. % of the alkane containing 2 to 6 carbon atoms and/or alkene containing 2 to 6 carbon atoms, with a mixed metal oxide catalyst containing molybdenum, vanadium, niobium and optionally tellurium; followed by contacting a second gas stream comprising oxygen and the alkane containing 2 to 6 carbon atoms and/or the alkene containing 2 to 6 carbon atoms with the catalyst.

The invention is for a method for making a heteropoly acid compound catalyst from compounds containing molybdenum, vanadium, phosphorus, cesium, copper, bismuth, antimony and boron in which molybdenum, vanadium, phosphorus, cesium, copper, bismuth and boron are at their highest oxidation states and antimony has a 3+ oxidation state. The catalyst contains oxides of molybdenum, vanadium, phosphorus, cesium, copper, bismuth, antimony, boron and, optionally, other metals. The catalyst has the formula:
Mo.sub.12V.sub.aP.sub.bCs.sub.cCu.sub.dBi.sub.eSb.sub.fB.sub.gO.sub.x
where Mo is molybdenum, V is vanadium, P is phosphorus, Cs is cesium, Cu is copper, Bi is bismuth, Sb is antimony, B is boron, O is oxygen, a is 0.01 to 5.0, b is 0.5 to 3.5, c is 0.01 to 2.0, d is 0.0-1.5, e is 0.0-2.0, f is 0.01-3.0, g is 0.0-4.0 and x satisfies the valences. Molybdenum is reduced by antimony and reoxidized during catalyst synthesis.

The invention is for a method for making a heteropoly acid compound catalyst from compounds containing molybdenum, vanadium, phosphorus, cesium, copper, bismuth, antimony and boron in which molybdenum, vanadium, phosphorus, cesium, copper, bismuth and boron are at their highest oxidation states and antimony has a 3+ oxidation state. The catalyst contains oxides of molybdenum, vanadium, phosphorus, cesium, copper, bismuth, antimony, boron and, optionally, other metals. The catalyst has the formula:
Mo.sub.12V.sub.aP.sub.bCs.sub.cCu.sub.dBi.sub.eSb.sub.fB.sub.gO.sub.x
where Mo is molybdenum, V is vanadium, P is phosphorus, Cs is cesium, Cu is copper, Bi is bismuth, Sb is antimony, B is boron, O is oxygen, a is 0.01 to 5.0, b is 0.5 to 3.5, c is 0.01 to 2.0, d is 0.0-1.5, e is 0.0-2.0, f is 0.01-3.0, g is 0.0-4.0 and x satisfies the valences. Molybdenum is reduced by antimony and reoxidized during catalyst synthesis.

Disclosed is a calcination apparatus, including: a calcination tube having open ends at both terminals; a pair of hoods, each hood covering each open end of the calcination tube; and a pair of rings, each ring sealing a gap between the calcination tube and the hood, wherein the rings are directly or indirectly fixed on an outer surface of the calcination tube; a groove is provided along a circumferential direction of the ring at a contact surface side between the ring and the hood; a sealed chamber surrounded by the hood and the groove is formed; and both the calcination tube and the rings rotate in a circumferential direction of the calcination tube while keeping the hood in contact with both sides of the groove.

Disclosed is a calcination apparatus, including: a calcination tube having open ends at both terminals; a pair of hoods, each hood covering each open end of the calcination tube; and a pair of rings, each ring sealing a gap between the calcination tube and the hood, wherein the rings are directly or indirectly fixed on an outer surface of the calcination tube; a groove is provided along a circumferential direction of the ring at a contact surface side between the ring and the hood; a sealed chamber surrounded by the hood and the groove is formed; and both the calcination tube and the rings rotate in a circumferential direction of the calcination tube while keeping the hood in contact with both sides of the groove.

The present invention relates to a catalyst based on iron oxide for the dehydrogenation of hydrocarbons and also a process for producing it. The catalyst comprises at least one iron compound, at least one potassium compound and at least one cerium compound, wherein the at least one iron compound and the at least one potassium compound are at least partly present in the form of one or more K/Fe mixed oxide phases of the general formula K.sub.xFe.sub.yO.sub.z, where x is from 1 to 17; y is from 1 to 22 and z is from 2 to 34, where the catalyst comprises at least 20% by weight, based on the total catalyst, of the K/Fe mixed oxide phases and comprises crystalline cerium dioxide having a crystallite size in the range from 10 nm to 30 nm.

The present invention relates to a catalyst based on iron oxide for the dehydrogenation of hydrocarbons and also a process for producing it. The catalyst comprises at least one iron compound, at least one potassium compound and at least one cerium compound, wherein the at least one iron compound and the at least one potassium compound are at least partly present in the form of one or more K/Fe mixed oxide phases of the general formula K.sub.xFe.sub.yO.sub.z, where x is from 1 to 17; y is from 1 to 22 and z is from 2 to 34, where the catalyst comprises at least 20% by weight, based on the total catalyst, of the K/Fe mixed oxide phases and comprises crystalline cerium dioxide having a crystallite size in the range from 10 nm to 30 nm.

The invention relates to the preparation of a catalyst containing: a mainly aluminium oxide calcined support; a hydro-dehydrogenating active phase containing at least one metal of group VIB, the process including: a) a first precipitation step of at least one basic precursor and at least one acidic precursor, b) a heating step, c) a second precipitation step by addition to the suspension of at least one basic precursor and at least one acidic precursor, d) a filtration step; e) a drying step, f) a moulding step, g) a heat treatment step; h) an impregnation step of the hydro-dehydrogenating active phase on the support obtained in the step g).