Patent ID: 7038082

Claim:
A process for preparing a multimetal oxide material M of the stoichiometry I: Mo 1 V a M 1 b M 2 c M 3 d O n (I), wherein M 1 is at least one of the elements selected from the group consisting of Te and Sb; M 2 is at least one of the elements selected from the group consisting of Nb, Ti, W, Ta and Ce; M 3 is at least one of the elements selected from the group consisting of Pb, Ni, Co, Bi, Pd, Ag, Pt, Cu, Au, Ga, Zn, Sn, In, Re, Ir, Sm, Sc, Y, Pr, Nd and Tb; a is from 0.01 to 1, b is from>0 to 1, c is from>0 to 1, d is from>0 to 0.5 and n is a number which is determined by the valency and frequency of the elements other than oxygen in (I), whose X-ray diffraction pattern has reflections h, i and k, whose peaks are at the diffraction angles (2θ) 22.2±0.5°(h), 27.3±0.5°(i) and 28.2±0.5°(k), the reflection h being the one with the strongest intensity within the X-ray diffraction pattern and having a full width at half height (FWHH) of not more than 0.5°, the intensity P i of the reflection i and the intensity P k of the reflection k satisfying the relationship 0.65≦R≦0.85, wherein R is the intensity ratio defined by the formula R=P i /(P i +P k ) and the FWHH of the reflection i and that of the reflection k being each±1°, but has no reflection having the peak position 2θ=50.0±0.3°; the process comprising washing the multimetal oxide material M with a liquid selected from the group consisting of organic acids, inorganic acids, solutions of organic acids, solutions of inorganic acids and mixtures thereof, wherein the multimetal oxide material M is prepared with the proviso that, in the course of the preparation of the multimetal oxide material M, no precursor multimetal oxide material of the multimetal oxide material M is washed with a liquid selected from the group consisting of organic acids, inorganic acids, solutions of organic acids, solutions of inorganic acids, solutions of inorganic acids and mixtures thereof.