Patent ID: 8415498

Claim:
A process for producing acrolein and/or acrylic acid, which comprises: conducting a catalytic gas-phase oxidation of a gas with molecular oxygen or a molecular oxygen-containing gas to obtain an acrolein and/or acrylic acid product, wherein an initial operation of the catalytic gas-phase oxidation is carried out under a first reaction temperature, and thereafter, a steady state operation of the catalytic gas-phase oxidation is carried out at a second reaction temperature that is lower than the first reaction temperature, and wherein, when the gas is propylene or a propylene-containing gas, the product is acrolein and/or acrylic acid and the catalytic gas-phase oxidation of the gas is carried out in the presence of an oxide catalyst comprising an active ingredient represented by the following formula (1): Mo 12 Bi a Fe b A c B d C e D f O x (1) wherein Mo is molybdenum, Bi is bismuth, Fe is iron, A is at least one element selected from the group consisting of colbalt and nickel, B is at least one element selected from the group consisting of alkali metals, alkaline earth metal and thallium, C is at least one element selected from the group consisting of tungsten, silicon, aluminum, zirconium and titanium, D is at least one element selected from the group consisting of phosphorus, tellurium, antimony, tin, cerium, lead, niobium, manganese, arsenic and zinc, O is oxygen, and a, b, c, d, e, f and x respectively denote atomic ratios of Bi, Fe, A, B, C, D and O wherein 0<a≦10, 0<b≦20, 2≦c≦20, 0<d≦10, 0≦e≦30, 0≦f≦4, and x is a value determined according to a state of oxidation of each element, and when the gas is acrolein or an acrolein-containing gas, the product is acrylic acid and the catalytic gas-phase oxidation of the gas is carried out in the presence of an oxide catalyst comprising an active ingredient represented by the following formula (2): Mo 12 V g W h Cu i E j F k G l H m O y (2) wherein Mo is molybdenum, V is vanadium, W is tungsten, Cu is copper, E is at least one element selected form the group consisting of colbalt, nickel, iron, lead and bismuth, F is at least one element selected from the group consisting of antimony, niobium and tin, G is at least one element selected from the group consisting of silicon, aluminum, titanium and zirconium, H is at least one element selected from alkali metals, O is oxygen, and g, h, i, j, k, l, m and y respectively denote atomic ratios of V, W, Cu, E, F, G, H and O wherein 2≦g≦15, 0≦h≦10, 0<i≦6, 0≦j≦30, 0≦k≦6, 0≦l≦60, 0≦m≦6, and y is a numerical value determined according to a state of oxidation of each element.