Abstract: Disclosed is a highly efficient continuous method for the aqueous extraction of water-soluble oxidation catalyst material from a residue such as that generated in the production of dimethyl terephthalate from p-xylene by the molecular oxygen oxidation and methanol esterification process. In the method the desired end product is an aqueous solution of the catalyst material. The residue to be extracted is established in finely dispersed condition in part of the aqueous solution at a weight ratio of aqueous solution to residue of above about 1:1 and maintained in that condition for a length of time sufficient for maximum transfer of catalyst material from the residue to the aqueous solution to take place. The resulting dispersion then is separated in a phase separation zone into an aqueous phase and an extracted residue phase. The separated aqueous phase is withdrawn from the phase separation zone as the aqueous solution.