Furan-2,5-dicarboxylic acid purge process

A process to produce a raffinate stream in a method for making a carboxylic acid, said process comprising:

• (i) oxidizing in an oxidation zone an oxidizable raw material stream comprising 5-(hydroxymethyl) furfural (5-HMF) in the presence of an oxidation solvent stream comprising a saturated organic acid having from 2-4 carbon atoms and a catalyst at a temperature of 100° C. to 220° C. to produce a crude carboxylic acid slurry;
• wherein said oxidation zone comprises at least one oxidation reactor;
• wherein said crude carboxylic acid slurry comprises furandicarboxylic acid;
• wherein said catalyst comprises cobalt, manganese and bromine;
• and wherein the yield of furandicarboxylic acid is greater than 90%;
• (ii) routing said crude carboxylic acid slurry to a solid liquid separation zone to produce a mother liquor stream comprising said catalyst and impurities;
• wherein said solid liquid separation zone comprises at least one pressure drum filter;
• (iii) routing at least a portion of said mother liquor stream to a mother liquor purge zone comprising a liquid-liquid extraction zone to produce an extract stream comprising impurities and an extract solvent, and a raffinate stream comprising catalyst solvent and oxidation catalyst;
• wherein at least a portion of said oxidation catalyst and/or catalyst solvent is optionally recycled to the oxidation zone;
• and wherein said oxidizable raw material stream comprises greater than 40% by weight of 5-HMF.