SDS Volume (2957)

Volume 66. Ammonium Phosphates, p None

Original Measurements

Farr, T. D.; Fleming, J. D.; J. Chem. Eng. Data 1965, 10. 20.

Variables:

Room Temp: Composition at 273 and 298 K. $\pu{K}$

Prepared by:

J. Eysseltová

Method/Apparatus/Procedure:

The complexes, in capped glass tubes, were equilibrated in a cold room or in a water bath. The approach to equilibrium was followed by periodic petrographic and X-ray examination of the solid phases and by analyses of the liquid phase. Phosphorus was determined gravimetrically as quinolinium molybdophosphate [1] and nitrogen by distillation of ammonia with $\ce{NaOH}$. pH was measured with a glass electrode. One-dimensional paper chromatography [2] was used to check the hydrolysis.

Source and Purity of Materials:

1. The ammonium pyrophosphates and their solutions were prepared by ammoniation and vacuum evaporation of 0.3 N $\ce{H4P2O7}$ that had been prepared by ion exchange from solutions of recrystallized tetrasodium pyrophosphate. All operations were carried out at temperatures below 10 °C. No significant hydrolysis of the pyrophosphate was observed.

Estimated Errors:

Ambient temperature: The only information given is that the temperature was kept constant as follows: ±0.5°C; 25 ±0.02°C.

References

¹ Perrin, C. H.; J. Assoc. Offic. Agr. Chemists 41, 758 (1958).
² Karl-Kroupa, E.; Anal. Chem. 28, 1091 (1956).