Abstract: The choice of phosphorus source compounds plays a pivotal role in the synthesis of phosphorus-based flame retardants. In addition to evaluating flame retardant efficiency, critical parameters such as chemical reactivity, thermal stability, and economic feasibility must be carefully considered. This study presents a comparative analysis of three distinct phosphorus sources: phosphorus oxychloride, hexachlorocyclotriphosphazene, and phytic acid, highlighting their respective advantages and limitations. Furthermore, we detail the synthetic procedures for three phosphorus-containing flame retardants and demonstrate their effectiveness in enhancing the flame resistance of polyurethane materials. These findings offer valuable guidance for the judicious selection of phosphorus sources in flame retardant design. The presented chemical reactions and characterization methodologies also serve as practical extensions to fundamental organic chemistry curricula, facilitating students’ comprehension of theoretical concepts through their application in research contexts.

Key words: Phosphorus source compounds, Phosphorus-containing flame retardants, Synthesis and characterization, Flame retardancy