Basf Aktiengesellschaft

Cornelia Dobner

Mark Duda

Sebastian Storck

Jens Weiguny

Raimund Felder

A process for preparing a vanadium, phosphorus, and oxygen catalyst precursor for preparing maleic anhydride by heterogeneously catalyzed gas-phase oxidation of a hydrocarbon having at least four carbon atoms, which comprises

Catalyst-precursor for the production of maleic acid anhydride and method for the production thereof

A process for preparing a vanadium, phosphorus, and oxygen catalyst precursor for preparing maleic anhydride by heterogeneously catalyzed gas-phase oxidation of a hydrocarbon having at least four carbon atoms, by reacting vanadium pentoxide (I) in the presence of a primary or secondary, noncyclic or cyclic, unbranched or branched, saturated alcohol having from 3 to 6 carbon atoms (II) with a pentavalent or trivalent phosphorus compound (III) in a temperature range from 80 to 160&#xb0; C. with stirring and subsequently filtering the resultant suspension, in which (a) the way in which the phosphorus compound (III) and the vanadium pentoxide (I) are combined in the presence of the alcohol (II), (b) the action of a stirring power of from 0.01 to 0.6 W/kg suspension, and/or (c) the filtration at a temperature from 65&#xb0; C. to 160&#xb0; C. are used to set a filtration resistance &#x3b1;&#xb7;&#x3b7; of &#x3c;50&#xb7;10mPa&#xb7;s/m; a catalyst precursor obtainable from this process; a process for preparing a catalyst from the catalyst precursor; a catalyst obtainable from this process; and a process for preparing maleic anhydride over this catalyst.

Disclosed is a method for producing a catalyst containing vanadium, phosphorus, and oxygen, which is used for oxidizing the gas phase of a hydrocarbon having at least four carbon atoms to maleic anhydride. According to the inventive method, a corresponding catalyst precursor which contains vanadium, phosphorus, and oxygen and is provided with particles having an average diameter of at least 2 mm is converted into a catalytically active form by means of calcination, and a flow of the catalyst precursor is transported on a conveyor belt across at least one calcination area over a distanceat an essentially steady speed in order to be calcinated. The variation over time of the gas temperature in relation to the set point value amounts to &#x2266;5&#xb0; C. at each position in the area of the flow of the catalyst precursor, which lies within the second half/2 of the calcination area, while the local difference in the gas temperature between any positions in the area of the flow of the catalyst precursor, which is located within the second half/2 of the calcination area, amounts to &#x2266;5&#xb0; C.

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Frankenthal, Germany

Cornelia Dobner