Process for producing geometric shaped catalyst bodies

Abstract

A process for producing geometric shaped catalyst bodies K whose active material is a multielement oxide of stoichiometry [Bi a Z 1 b O x ] p [Bi c Mo 12 Fe d Z 2 e Z 3 f Z 4 g Z 5 h Z 6 i O y ] 1 , in which a finely divided oxide Bi a Z 1 b O x and, formed from element sources, a finely divided mixture of stoichiometry Bi c Mo 12 Fe d Z 2 e Z 3 f Z 4 g Z 5 h Z 6 i are mixed in a ratio of p:1, this mixture is used to form shaped bodies and these are treated thermally, where 0<c≦0.8.

1 . A geometric shaped catalyst body K which comprises, as an active material, a multielement oxide I of the general stoichiometry I
   [Bi a Z 1   b O x ] p [Bi c Mo 12 Fe d Z 2   e Z 3   f Z 4   g Z 5   h Z 6   i O y ] 1   (I),
   where   Z 1 =tungsten or tungsten and molybdenum, with the proviso that at least 10 mol % of the molar total amount of Z 1  is tungsten,   Z 2 =one element or more than one element from the group consisting of nickel and cobalt,   Z 3 =one element or more than one element from the group consisting of the alkali metals, the alkaline earth metals and thallium,   Z 4 =one element or more than one element from the group consisting of zinc, phosphorus, arsenic, boron, antimony, tin, cerium, vanadium and chromium,   Z 5 =one element or more than one element from the group consisting of silicon, aluminum, titanium, tungsten and zirconium,   Z 6 =one element or more than one element from the group consisting of copper, silver, gold, yttrium, lanthanum and the lanthanides,   a=0.1 to 3,   b=0.1 to 10,   d=0.01 to 5,   e=1 to 10,   f=0.01 to 2,   g=0 to 5,   h=0 to 10,   i=0 to 1,   p=0.05 to 6, and   x, y=numbers determined by the valency and frequency of the elements in I other than oxygen,   which shaped catalyst body is obtainable by a process in which
 a finely divided mixed oxide Bi a Z 1   b O x  with a particle diameter d 50   A1 , as starting material A1, is preformed with the proviso that 1 μm≦d 50   A1 ≦100 μm; 
 sources of the elements other than oxygen in the component T=[Bi c Mo 12 Fe d Z 2   e Z 3   f Z 4   g Z 5   h Z 6   i O y ] 1  of the multielement oxide I are used in an aqueous medium to obtain an intimate aqueous mixture M, with the proviso that
 each of the sources used, in the course of preparation of the aqueous mixture M, passes through a degree of division Q for which its diameter d 90   Q  is ≦5 μm, and 
 the aqueous mixture M comprises the elements Bi, Mo, Fe, Z 2 , Z 3 , Z 4 , Z 5  and Z 6  in the stoichiometry I*
   Bi c Mo 12 Fe d Z 2   e Z 3   f Z 4   g Z 5   h Z 6   i   (I*);
 
 
 the aqueous mixture M, by means of drying and adjusting the degree of division d 90   A2 , is used to obtain a finely divided starting material A2 with a particle diameter d 90   A2 , with the proviso that 400 μm≧d 90   A2 ≧10 μm; 
 starting material A1 and starting material A2, or starting material A1, starting material A2 and finely divided shaping assistant, are mixed with one another to form a finely divided starting material A3, with the proviso that the starting material A3 comprises the elements other than oxygen introduced into the starting material A3 via starting materials A1 and A2 in the multielement oxide I in the stoichiometry I**
   [Bi a Z 1   b ] p [Bi c Mo 12 Fe d Z 2   e Z 3   f Z 4   g Z 5   h Z 6   i ] 1   (I**),
 
 
 finely divided starting material A3 is used to form geometric shaped bodies V, and 
 the shaped bodies V are treated thermally at elevated temperature to obtain the geometric shaped catalyst bodies K, 
 
   wherein the stoichiometric coefficient c satisfies the condition 0<c≦0.8, and   wherein all particle diameters are based on volume-based particle diameter distribution determined according to ISO 13320 at a dispersion pressure of 2 bar absolute   
     
     
         2 . A catalyst obtainable by grinding a shaped catalyst body which is a shaped unsupported catalyst body and is obtainable by a process according to  claim 1 . 
     
     
         3 . A process comprising heterogeneously catalyzed partial gas phase oxidation of an alkane, alkanol, alkanal, alkene and/or alkenal which comprises from 3 to 6 carbon atoms over a catalyst bed, wherein said catalyst bed comprises a shaped catalyst body according to  claim 1 . 
     
     
         4 . A process comprising heterogeneously catalyzed partial gas phase oxidation of an alkane, alkanol, alkanal, alkene and/or alkenal which comprises from 3 to 6 carbon atoms over a catalyst bed, wherein said catalyst bed comprises a catalyst according to  claim 2 . 
     
     
         5 . The process according to  claim 3 , which is a process for heterogeneously catalyzed partial gas phase oxidation of propene to acrolein. 
     
     
         6 . The process according to  claim 4 , which is a process for heterogeneously catalyzed partial gas phase oxidation of propene to acrolein. 
     
     
         7 . The process according to  claim 3 , which is a process for heterogeneously catalyzed partial gas phase oxidation of isobutene to methacrolein. 
     
     
         8 . The process according to  claim 4 , which is a process for heterogeneously catalyzed partial gas phase oxidation of isobutene to methacrolein. 
     
     
         9 . The process according to  claim 3 , which is a process for ammoxidation of propene to acrylonitrile or a process for ammoxidation of isobutene to methacrylonitrile. 
     
     
         10 . The process according to  claim 4 , which is a process for ammoxidation of propene to acrylonitrile or a process for ammoxidation of isobutene to methacrylonitrile. 
     
     
         11 . The geometric shaped catalyst body K according to  claim 1 , wherein the geometric shaped body V is a ring. 
     
     
         12 . The geometric shaped catalyst body K according to  claim 11 , wherein the side crushing strength SCS of the annular shaped body V satisfies the condition 12 N≦SCS≦25 N. 
     
     
         13 . The geometric shaped catalyst body K according to  claim 1 , wherein the geometric shaped body V is a sphere. 
     
     
         14 . The geometric shaped catalyst body K according to  claim 1 , wherein the geometric shaped body V is a solid cylinder. 
     
     
         15 . The geometric shaped catalyst body K according to  claim 11 , wherein the external diameter=from 2 to 10 mm, the height=from 2 to 10 mm and the wall thickness of the ring is from 1 to 3 mm. 
     
     
         16 . The geometric shaped catalyst body K according to  claim 12 , wherein the external diameter=from 2 to 10 mm, the height=from 2 to 10 mm and the wall thickness of the ring is from 1 to 3 mm. 
     
     
         17 . The geometric shaped catalyst body K according to  claim 13 , wherein the sphere diameter is from 2 to 10 mm. 
     
     
         18 . The geometric shaped catalyst body K according to  claim 14 , wherein the external diameter=from 1 to 10 mm and the height of the solid cylinder is from 2 to 10 mm.