Abstract: Catalyst particles of an active material of the general formula[Mo,V,W].sub.12 Bi.sub.a [Fe,Ce].sub.b [Ni,Co,Zn].sub.C [Alkali].sub.d [P,As,Sb,B].sub.e [Si,Al,Ti].sub.f O.sub.xwherea is from 0.1 to 5,b is from 0.1 to 10,c is from 1 to 15,d is from 0.01 to 2,e is from 0 to 2,f is from 0 to 30 andx is the number of oxygen atoms required to saturate the valences of the other components,have the shape of a 3-spoked to 5-spoked wheel or of a rosette which have wall thicknesses of from 0.5 to 4 mm and a diameter of from 3 to 20 mm.

Abstract: A process and device for charging a plurality of tubes in a tube reactor with granular solids, preferably with catalysts, which, for this purpose, are fed from one or more stock vessels to a controllable metering device and from there, via guiding and directing devices and flexible hose connections, successively into the tubes to be filled, wherein, during the packing of the tubes, a stream of gas of constant amount is generated, which can, after an individual tube has been packed, be passed temporarily, via one or more controllable valves, through this packed tube, a pressure drop measurement being carried out at the same time and the differential between the measured value and the predetermined intended value being used to determine a small additional amount of packing material which is subsequently introduced into the tube which has been subjected to measurement, and wherein thereafter a program control triggers the mechanical packing of the next tube, metered in the same manner, with subsequent pressure d

Abstract: A mechanical process for filling the tubes (3) of tubular reactors with granular solids, e.g. catalysts, wherein two or more streams of material, e.g. of different catalytic activity, can be introduced in a controlled manner into each tube (3) which is to be filled, from two or more stock vessels (1,2) via two or more dispensing devices (MI, MZ) mounted above the upper tube end plate (13). By this process, different thermal/catalytic reaction profiles can be achieved over the length of the tube, or in certain groups of tubes within the tubular reactor, with substantially less time being required for filling the tubes (3).

Abstract: Catalysts which consist of a molded carrier, the surface of which is coated with an active catalyst composition of the general formula Mo.sub.12 A.sub.a B.sub.b C.sub.c D.sub.d O.sub.x, where A is V and/or W, B is Cu and/or Fe and/or Mn and/or Ni and/or Cr, C is Nb and/or Ta and/or Bi and/or Sb and/or Sn and/or Th and/or Ce and/or U, D is Li and/or Na and/or K and/or Rb and/or Cs and/or Tl and a is from 0.1 to 18, b is from 0 to 8, c is from 0 to 10, d is from 0 to 2 and x is from 36 to 135, which are particularly active and selective for the oxidation of acrolein and methacrolein with oxygen-containing gases to give acrylic acid and methacrylic acid, respectively, are obtained by first manufacturing the catalyst composition, before applying it to the carrier, from thermally easily decomposed salts of the components by mixing aqueous solutions, slurries or moist solid masses of the salts of the components, drying the mixture and calcining the dried composition at from 140.degree. to 600.degree. C.