Development of a Scalable Method for the Synthesis of Ethoxy(pentafluoro)cyclotriphosphazene

Ethoxy(pentafluoro)cyclophosphazene (1) exhibits excellent flame retardancy and various biological activities, and there are numerous synthesis methods available. However, most of these methods have certain problems and shortcomings, such as the use of expensive raw materials and toxic and harmful reagents. To address these issues and uncertainties, we reported the development of a facile and sustainable synthesis method of 1, which involves only two concise chemical steps. In this process, the first step contains the reaction of hexachorocyclotriphosphazene (3) with sodium fluoride to yield hexafluorocyclotriphosphazene (2). The second step includes ethoxylation using an ethoxylation reagent, ethanol, and sodium hydroxide as an acid-binding agent to produce 1 with good quality and an overall yield of 76%. Several advantages are offered by this new synthetic approach, including good reactivity, high yield, low cost, environmental friendliness, and, finally, being industrially viable. The optimized process has been successfully demonstrated on a large scale to support the development of the new energy electric vehicle industry.