Heterogeneous-phase reaction of glycidyl methacrylate and chondroitin sulfate: Mechanism of ring-opening-transesterification competition

Addressing the different solubility/miscibility of the water-soluble CS and the water-insoluble GMA, a slow heterogeneous-phase reaction of CS with GMA was designed and performed in aqueous medium regardless of GMAs potential side-reaction with water. By monitoring the methacrylate-conjunction with NMR, a different reaction mechanism was discovered. Two reactions, including a rapid reversible transesterification and a slow irreversible ring-opening conjugation, took place simultaneously. As the reaction proceeded, there was a decline in the amount of transesterification products, while the concentration of ring-opening products gradually increased with time.