Acta Phys. -Chim. Sin. ›› 1998, Vol. 14 ›› Issue (09): 794-798.doi: 10.3866/PKU.WHXB19980906

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Spectroscopic Properties of Potassium Saponified HEHPEHE and the Formation of w/o Microemulsions

Li Yan, Li Quan, Zhou Wei-Jin, Wu Jin-Guang   

  1. State Key Laboratory of Rare Earth Materials Chemistry and Applications,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871
  • Received:1997-12-26 Revised:1998-03-03 Published:1998-09-15
  • Contact: Wu Jin-Guang


The properties of potassium saponified 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (HEHPEHE or P507) as well as the formation of microemulsions (water/(K,H )EHPEHE/n-heptane)have been investigated by means of Fourier Transform Infrared Spectroscopy(FT-IR).The stretching bands of P-O-H and the P-O-C shift with the saponification due to the interaction of HEHPEHE and the saponified resultant (KEHPEHE), named acid-salt system. The absorbance of P-O-H stretching vibration varies to lower frequencies while P-O-C stretching band shifts to higher wavenumbers with the increases of saponification. Furthermore, the P-O-C stretching band splitted into two distinct peaks after the saponification exceed 60%.Water/(K,H) EHPEHE/n-heptane microemulsions could be formed when the saponification was higher than 60% . The water solubility and the average diameter of droplets in microemulsion reach their maxima at the saponification of 75%.

Key words: 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester(HEHPEHE or P507), Microemulsions, Acid-salt system, FT-IR, Laser-scattering