Abstract: Processes for the liquid phase oxidation of one or more of a para- or a meta-substituted dialkyl aromatic compound are disclosed, the processes including a step of combining in a reaction medium the one or more para- or meta-substituted dialkyl aromatic compound, a solvent mixture comprising water and a saturated organic acid having from 2-4 carbon atoms, and an oxygen-containing gas, at a temperature from about 130° C. to about 180° C., in the presence of a catalyst composition comprising cobalt, manganese, bismuth, and bromine. The processes produce the corresponding aromatic dicarboxylic acid product with improved conversion, while reducing the formation of carbon oxides.