The Iodine value (IV) also called “Iodine number or Iodine absorption value” is an important analytical characteristic of unsaturation of fats and oils. It is expressed as the “ number of grams of iodine that will react with the double bonds in 100 grams of fats, oils, and waxes.” Saturated oils, fats, and waxes take up no iodine; therefore their iodine value is zero; but unsaturated oils, fats, and waxes take up iodine. Unsaturated compounds contain molecules with double (-C=C-) or triple (C≡C-) bonds, which are very reactive toward iodine. The more iodine is attached, the higher is the iodine value, and more reactive, less stable. In performing the test, a known excess of iodine, usually in the form of iodine monochloride (ICl), is allowed to react with a known weight of the oil, fat or wax, and then the amount of iodine remaining unreacted is determined by titration using of sodium thiosulfate volumetric standard solution.
International Journal of Chemistry and Pharmaceutical Sciences.
2019.