METHOD FOR PREPARING ACRYLIC ACID

Provided is a process for preparing acrylic acid comprising (1) preparing acrolein by catalytic gas phase oxidation comprising (a) providing a reaction gas comprising (i) 5 to 10 mol % propylene, (ii) 0.02 to 0.75 mol % propane, and (iii) 0.25 to 1.9 mol % of a fuel mixture comprising at least one of methane and ethane, wherein the molar ratio of the total amount of propane, methane, and ethane to the total amount of propylene is from 0.01:1 to 0.25:1, (b) contacting the reaction gas with a first mixed metal oxide catalyst to form a mixture comprising acrolein, wherein the first mixed metal oxide catalyst comprises one or more of molybdenum, bismuth, cobalt, and iron, and (2) contacting the acrolein mixture with a second mixed metal oxide catalyst to form a mixture comprising acrylic acid, wherein the second mixed metal oxide catalyst comprises one or more of molybdenum, vanadium, tungsten, copper, and antimony.