Preparation of Diglycolic Acid via Oxidation of Diethylene Glycol with Molecular Oxygen

Diglycolic acid was synthesized by the reaction of diethylene glycol and oxygen under heterogeneous conditions using water as solvent and Bi-Pt/C as catalyst.The structure of the product was confirmed by IR,1HNMR spectra,etc.The effects of temperature,volumes of solvents,amount of catalysts,amount of oxygen and reaction time on the reaction were studied.The optimum conditions were found as follows:reaction temperature 80 ℃,reaction time 8 h,mass ratio of substrate to catalyst 30,volume ratio of water to substrate 30,oxygen flow 40 mL/min.Under these conditions,the average yield of diglycolic acid was 95.0%.The catalyst activity did not show any significant decrease after six recycles.