RECOVERY OF TRIMELLITIC ACID FROM PSEUDOCUMENE LIQUID PHASE OXIDATION EFFLUENT

摘要

Enhanced recovery of trimellitic acid from liquid phase oxidation effluent that contains a substantial portion of the acid product as solute in acetic acid solvent by concentrating the effluent by use of heat values in the effluent to precipitate a first crop of acid product, displacing and replacing mother liquor with fresh acetic acid of low water content to a first slurry of 60 to 70 percent solids and 40 to 30 percent liquid, further concentrating displaced effluent mother liquor by removal of 80 to 90 percent of its solvent content, displacing and replacing the remaining 20 to 10 percent of solvent with fresh acetic acid of low water content to a second slurry of 60 to 70 percent solids and 40 to 30 percent liquid, combining and removing solvent from the first and second slurries. Advantageously by the use of those steps heat is not wasted, conventional crystallization is avoided and apparatus is minimized by the practice of that combination of procedural steps. The recovered trimellitic acid product can be converted to its intramolecular anhydride or inter- and intra-bis-anhydride.