Studies of the Formation Mechanism of Sodium Tripolyphosphate from Orthophosphates by the Use of Radioisotopes

The reaction process of an equimolar mixture of mono- and disodium orthophosphates was examined to serve as a reference for the considerations of the mechanism of the formation of sodium tripolyphosphate. Differential thermoanalysis, thermogravimetric analysis, X-ray diffraction analysis and thin-layer chromatographic analysis were done. Particularly, the reaction mechanisms (the formation of liquid Na3HP2O7, etc.) were also examined by the use of the “32P” radioisotope. The reaction process is as follows: (Remark: Graphics omitted.) A feedback phenomenon of Na2H2P2O7 was observed.