A New Route for the Synthesis of Alkali Polyphosphate from Economical Starting Materials: Part II—Influence of Reaction Conditions

Abstract

Direct synthesis of sodium cyclotriphosphate, Na₃P₃O₉ (SCTP), from sodium chloride and orthophosphoric acid as economical starting materials was investigated. Reaction conditions including the heating rate, reaction plateau time, air flow rate, and Na/P molar ratio were found to be key parameters for the elimination of chloride and for the selectivity in SCTP. High yields in SCTP (94–99%) were obtained. The results are very interesting with respect to a potential industrial application for the synthesis of SCTP from point of view of the low cost of the starting materials.

GRAPHICAL ABSTRACT

Keywords:

• Sodium polyphosphate
• sodium cyclotriphosphate
• sodium chloride
• orthophosphoric acid
• thermal synthesis

Acknowledgments

The authors thank colleagues at RAPSODEE (Research Centre in Albi on Particulate Solids, Energy and the Environment) for their technical help.