PROCESS FOR ALDEHYDE BYPRODUCT REDUCTION IN ACRYLIC ACID PRODUCTION USING HIGHLY ACTIVE AND SELECTIVE CATALYSTS

摘要

A catalyst composition comprises an acrolein-oxidizing catalyst comprising a mixed metal oxide catalyst of general formula (I): MoV_aA¹_bA²_cA³_dO_m in which A¹ comprises at least one element selected from the group consisting of W and Cu; A² comprises at least one element selected from the group consisting of Sb, Fe, and Nb; A³ comprises at least one element selected from the group consisting of Y, Ti, Zr, Hf, Ta, Cr, Mn, Re, Ru, Co, Rh, Ir, Ni, Pd, Pt, Ag, Au, Zn, B, Al, Ga, In, Ge, Sn, Si, Te, Pb, P, As, Bi, Se, rare earth elements, alkaline elements, and alkaline earth elements; a ranges from 0.01 to 1.0; b ranges from 0.01 to 1.5; c ranges from 0 to 1.5; d ranges from 0 to 1.0; and m is dependent on the oxidation state of the other elements. The catalyst composition further comprises a finishing catalyst comprising a mixed metal oxide catalyst of general formula (II): MoV_wNb_xX¹_y X²_zO_n in which X¹ comprises at least one element selected from the group consisting of Te and Sb; X² comprises at least one an element selected from the group consisting of Y, Ti, Zr, Hf, Nb, Ta, Cr, Mn, Re, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Ag, Au, Zn, B, Al, Ga, In, Ge, Sn, Pb, P, As, Bi, Se, rare earth elements and alkaline earth elements; w ranges from 0.01 to 1.0; x ranges from 0.01 to 1.0; y ranges from 0.01 to 1.0; z ranges from 0 to 1.0; and n is depended on the oxidation state of the other elements. The finishing catalyst does not contain W or Cu, and has an X-ray diffraction pattern showing an orthorhombic phase as the major crystal phase with main peaks with 2θ at 6.7°, 7.8°, 22.1°, and 27.2°. The acrolein-oxidizing catalyst has a different chemical composition than the finishing catalyst. A process for producing acrylic acid is also disclosed.