Vapor phase oxidation of acrolein to acrylic acid

A process for the selective vapor phase oxidation of acrolein to acrylic acid in a recirculating solids reactor system using particulate molybdenum vanadate multimetal oxide in oxidized form as oxidant comprising:

• (a) contacting a feed gas containing from 1 mol % to 100 mol % acrolein, 0 to 20 mol % oxygen, 0 to 70 mol % water, and the remainder inert gas with an effective amount of an oxidant comprising a particulate molybdenum vanadate multimetal oxide in oxidized form and having a particle size range of 10 to 300 micrometers, in a transport bed reactor at a temperature of about 250 to about 450° C., with a gas residence time in the reaction zone from 1 second to 15 seconds, and with a solids residence time in the reaction zone from 2 seconds to 120 seconds;
• (b) removing and recovering acrolein from the effluent gases produced in the transport bed reactor of step (a) by separating the resultant reduced particulate molybdenum vanadate multimetal oxide from the effluent gases;
• (c) transporting the reduced particulate molybdenum vanadate multimetal oxide to a regenerator zone of the recirculating solids reactor system;
• (d) oxidizing the reduced particulate molybdenum vanadate multimetal oxide in the regenerator zone using an oxygen containing gas, at a temperature of from 250 to 500° C. at a solids residence time in the regenerator zone of from 0.5 minute to 10 minutes, and at an oxygen-containing gas residence time of from 3 seconds to 30 seconds;
• and
• (e) recycling the oxidized particulate molybdenum vanadate multimetal oxide from step (d) to the transport bed reactor.