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Solubility of linoleic acid in aqueous solutions and its reaction with water
Author(s) -
Mabrouk Ahmed Fahmy,
Dugan L. R.
Publication year - 1961
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02633110
Subject(s) - linoleic acid , chemistry , aqueous solution , conjugated linoleic acid , solubility , chromatography , fatty acid , organic chemistry
In a study of stable emulsions of linoleic acid in 0.1M‐KH 2 PO 4 /Na 2 HPO 4 buffer solutions prepared by sonic vibrations, the influence of linoleic acid on pH was manifested in buffer solutions of pH 8.00 and decreased gradually till it became negligible in pH 4.50. This change in pH values was due to differences in solubility of linoleic acid in the buffer solutions. Ultraviolet spectra of soluble linoleic acid in buffer solutions indicated the presence of conjugated dienes, which increased with the increasing of the pH of the system. Unbuffered aqueous emulsions of linoleic acid had a pH value which ranged between 4.69 and 5.10. Saturated aqueous solutions, obtained by high‐speed centrifugation, had concentrations of 15.80 to 16.00 mg. linoleic acid per 100 ml. of D.I. water. From the solubility data and conductivity values of linoleic acid the apparent classic and thermodynamic ionization constants were calculated to be 6.974±0.023×10 −6 and 6.905±0.017×10 −6 at 0.7°C. and 1.730±0.009×10 −5 and 1.689±0.007×10 −5 at 25°C., respectively. The result of the chemical interaction of linoleic acid and water is a saturated hydroxy fatty acid. This acid gave a positive test for glycol groups with periodic acid oxidation test and appeared to be a tetrahydroxy compound with the exact structure unknown.