Patent ID: 7795469

Claim:
A process for producing acrylic acid by vapor phase oxidation reaction of propane, propene, and mixtures thereof, using a reaction system having at least two reaction zones arranged in series with one another and at least one catalyst capable of catalyzing the vapor phase oxidation reaction disposed in each of the at least two reaction zones, wherein at least one intermediate effluent stream exits a preceding one of the at least two reaction zones and is at least partially fed to a subsequent one of the at least two reaction zones, and wherein said at least one catalyst comprises a three dimensional support and a mixed metal oxide having the empirical formula: Mo a V b N c X d O e wherein N is at least one element selected from the group consisting of Te and Se; X is at least one element selected from the group consisting of Nb, Ta, Ti, Al, Zr, Mn, Fe, Ru, Co, Rh, Ni, Pt, B, In, As, Ge, Sn, Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Hf, Pb, P, Pm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu; and wherein a, b, c, d and e are, respectively, the atomic ratios of molybdenum, vanadium, N, X and oxygen, and when a=1, b=0.01 to 1.0, c=0.01 to 1.0, d=0.01 to 1.0, and e is dependent on the oxidation state of the other elements, said process comprising the steps of: separating the at least one intermediate effluent stream by cooling the at least one intermediate effluent stream such that at least a portion of the acrylic acid condenses out of the at least one intermediate effluent stream to form at least an intermediate product stream comprising acrylic acid and an intermediate feed stream comprising starting materials selected from the group consisting of unreacted propane, unreacted propene, and mixtures thereof; feeding the intermediate feed stream to the subsequent reaction zone; and feeding an oxygen-containing gas to the subsequent reaction zone.