How to Synthesise High Purity, Crystalline d‐Glucaric Acid Selectively

Glucaric acid has potential applications in food, pharmaceutical and polymer industries yet no methodology exists within the public domain for isolation of this key bio‐derived platform molecule as a pure, crystalline solid. Here we demonstrate the difficulties, which arise in doing so and report development of a process for derivation of free‐glucaric acid from its Ca(2+)/K(+) glucarate salts, which are both commercially available. Employing Amberlyst‐15 (H(+)) exchange resin and azeotrope drying, powdered glucaric acid is prepared at > 99.96 % purity in 98.7 % dry yield.