The present study aimed at developing a new keto acid precursor for the oxidation of lambda-carrageenan via alkaline permanganate. A new class of keto-acid derivatives of lambda-carrageenan (LCAR), in the form of sulfated polysaccharides, was synthesized by oxidizing LCAR with permanganate ions in an alkaline environment at pH levels greater than 12. The reactants MnO4-, LCAR, and NaF were combined in precise stoichiometric ratios in alkaline solutions with pH values above 12. The mixture was stirred for approximately 48 hours to complete the reaction. The resulting colloidal precipitate of MnF4 was separated via filtration. The filtrate was then concentrated to approximately one-fifth of its initial volume using a rotary evaporator, followed by acidification with acetic acid to a pH range of 5-6. Vacuum evaporation was used to remove excess moisture, and the product was stored aside for future use. The oxidation product was confirmed using hydroxyl amine and 2,4-dinitrophenyl hydrazine, leading to the construction of the corresponding 2,4-dinitrophenyl hydrazone and dioxime derivatives. These results indicate the successful synthesis of ketoacid-LCAR as the final oxidation product. This innovative oxidation product shows great potential for applications in pharmaceuticals, medicine, biomedicine, and the food industry.
