Reactor for the efficient oxidation of alkyl aromatic compounds

A reactor for oxidizing an alkyl aromatic compound into an aromatic carboxylic acid, comprising:

• a) a reaction vessel with a centrally cylindrical inner wall having a plurality of vertical baffles extending inwardly from, and spaced around the inner periphery of, the inner wall;
• b) an agitation element positioned within said vessel, said agitation element comprising a vertical rotable shaft, said rotable shaft having a plurality of impellers spaced vertically therealong with each impeller having a plurality of blades having upper and lower edges;
• c) means for feeding a liquid reaction mixture, containing said alkyl aromatic compound, into said reaction vessel in a feeding zone located adjacent the second lowermost impeller, said zone being:
• i) vertically defined by an upper limit defined by a line perpendicular to said shaft and passing through about half the height of the blades of the second lowermost impeller and by a lower limit defined by a line perpendicular to said shaft and located below the lower edge of the blades of the second lowermost impeller at about ⅓ the distance from the lower tip of the blades of the second lowermost impeller to the blades of the lowermost impeller, measured downwards from said lower edge of the blades of the second lowermost impeller;
• and
• ii) radially defined by an outer circle line located at about 0.1 times the vessel diameter measured from the tip of the blades of the second lowermost impeller towards the inner wall of said reaction vessel, and an inner circle line located at about ⅔ of the radius of the blades of the second lowermost impeller measured from said shaft towards the outer tip of the blades of the second lowermost impeller;
• d) means for separately feeding a gaseous oxidizing agent into a liquid containing said alkyl aromatic compound when present within said reaction vessel;
• and
• e) means for withdrawing an aromatic carboxylic acid product from said reaction vessel;
• and said means for feeding said reaction mixture is not contacted by rotation of said agitation element.