METHOD OF RECOVERING HIGH-PURITY TEREPTHALIC ACID FROM TEREPHTHALIC ACID-CONTAINING WASTE LIQUIR

摘要

PURPOSE:In obtaining the titled substance useful as a synthetic raw material for polyester synthetic yarn from terephthalic acid-containing waste liquir, to improve easily purity of terephthalic acid, by neutralizing the waste liquor with an acid, making it further weakly acidic, precipitating partially the titled substance, filtering it, making the filtrate acidic. CONSTITUTION:Terephthalic acid-containing waste liquor produced in a process for providing polyester synthetic fibers is neutralized with an acid, made further into 4-6pH of weak acidity, terephthalic acid is partially precipitated and fitered. The filtrate is further acidified with an acid, the precipitated titled compound is filtered, washed with water and collected. When terephthalic acid coprecipitated with impurities is filtered, and active carbon, preferably active carbon with 8-hydroxyquinoline spreader is used, to give a product having higher purity.