Process and catalyst for preparing acetic acid by catalytic oxidation of ethane

A process for the selective preparation of acetic acid from a gaseous feedstock of ethane, ethylene or mixtures thereof, and oxygen or oxygen-containing gases, at elevated temperature on a tungsten-containing catalyst which comprises the elements W, X, Y and Z in the gram-atom ratios a:b:c:d in combination with oxygen

• WaXbYcZd I
• in which
• X is at least one element selected from the group consisting of Pd, Pt, Ag and Au,
• Y is a plurality of elements selected from the group consisting of V, Nb, Cr, Mn, Fe, Sn, Sb, Cu, Zn, U, Ni and Bi,
• Z is at least one element selected from the group consisting of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Sc, Y, La, Ti, Zr, Hf, Ru, Os, Co, Rh, Ir, B, Al, Ga, In, Ti, Si, Ge, Pb, P, As and Te,
• a is 1,
• b is a number from 0.0001 to 0.5,
• c is a number from 0.1 to 1.0, and
• d is a number from 0 to 2, with the proviso that the catalyst contains, as Y, at least the elements V and Nb.