Patent ID: 7015355

Claim:
A continuous process for the selective preparation of acetic acid from a gaseous feed of ethane, ethylene or mixtures thereof and oxygen at elevated temperature, in which the gaseous feed is brought together with a catalyst comprising the elements Mo, Pd, X and Y in gram-atom ratios a:b:c:d in combination with oxygen Mo a Pd b X c Y d I where the symbols X and Y are as defined below: X is one or more elements selected from the group consisting of Cr, Mn, Ta, Ti, V, Te and W, Y is one or more elements selected from the group consisting of B, Al, Ga, In, Pt, Zn, Cd, Bi, Ce, Co, Rh, Ir, Cu, Ag, Au, Fe, Ru, Os, K, Rb, Cs, Mg, Ca, Sr, Ba, Nb, Zr, Hf, Ni, P, Pb, Sb, Si, Sn, Ti and U but shall be at least Nb; the indices a, b, c and d are the gram-atom ratios of the corresponding elements, where a=1; b=from 0.0001 to 0.01; c=from 0.04 to 1; and d=from 0.005 to 1, and in which the residence times and the composition of the gaseous feed are selected in such a way that the space-time yield in the oxidation to acetic acid is >470 kg/(hm 3 ), with the proviso that the catalyst is obtained by the use of a niobium ammonium carboxylate as niobium source.