Methods for producing aromatic carboxylic acids

Abstract

A method of this invention produces an aromatic carboxylic acid, by oxidizing an aromatic compound B with oxygen in the presence of a catalytic nitrogen-containing cyclic compound A to thereby yield a corresponding aromatic carboxylic acid, the aromatic compound B having one or more hydrocarbon groups alone as substituents on its aromatic ring, and the catalytic nitrogen-containing cyclic compound A having a skeleton represented by following Formula (i): wherein X represents oxygen atom or an —OR group, and wherein R represents hydrogen atom or a hydroxyl-protecting group, as a constitutive member of its ring. The method includes the step of carrying out a reaction at a concentration of the aromatic compound B in the reaction system of 3.0 percent by weight or less, while continuously feeding the catalytic nitrogen-containing cyclic compound A, the aromatic compound B, a reaction solvent, and oxygen to a reactor and continuously extracting a reaction mixture from the reactor. This method can produce aromatic carboxylic acids with industrially good productivity without the need for special reaction facilities and without undergoing many steps.

Dependencies are inferred from the claim text.