Definition:
The iodine value is the amount of iodine (in grams) that is absorbed by 100 grams of fat or oil.
It measures the degree of unsaturation (double bonds) in the fatty acids.
Significance:
Indicates the unsaturation level of the fat or oil; higher iodine values mean more double bonds (unsaturated fats).
Used to differentiate between drying oils (high IV), semi-drying oils, and non-drying oils (low IV).
Important in industries like paint and varnish manufacturing.
Principle:
The fat or oil is reacted with a halogen (usually iodine monochloride, ICl) that adds across the double bonds.
The unreacted iodine is then titrated with sodium thiosulfate, and the iodine value is calculated based on the difference between the blank and the sample.
Equation of Iodine Value:
