What is the iodine value?
iodine value or iodine adsorption is used in analytical chemistry to measure the amount of non -mounting oils and fats. Animal and vegetable oils and fats - known chemically as triglycerides - have carbon atoms that can connect with hydrogen. When carbon atoms in these chains are associated with the maximum possible number of hydrogen atoms, the triglyceride is reported to be saturated, but if there is one or more double bonds between carbon atoms, there is less hydrogen in the molecule and the fat is reportedly unspecified. One double binding triglycerides are known as mononaturates and trigly with more than one double binding are known as polyunsaturate. Iodine can be combined with fats that have a double bonds, and therefore the number of such bonds can be derived from the amount of iodine they will be combined with. One electrons short before stable configuration and can create stable compounds by sharing electron pair with another atom. In carbon binding of a hydrogen binding are the only electron and one electron out of the carbonShared to create one covalent bond. Where the carbon is double binding in unsaturated fat, each of the carbon atoms can instead create a binding with halogen.
The more carbon double bonds have unsaturated fat, the more halogen atoms they can combine with. It is therefore possible to determine the degree of fat non -mounting by allowing it to be combined with halogen. A simple unsaturated fat test is to mix fat with a bromine solution in carbon tetrachloride; If the fat is unsaturated, brown or yellow bromine color disappears when combined with fat. However, iodine is usually used to determine the degree of non -mounting because it is easy to measure how much iodine has been used.
To obtain the iodine value - also known as iodine number - fat, the known amount is dissolved in a suitable solvent such as chloroform, and mixed with an excess of iodine in the form of iodine monochloride (ICL) because it reacts more. Where whereThere is a carbon double bond, one carbon atom will form one binding with chlorine in the iodine monochloride and the other with iodine. When the reaction is completed, iodide iodine is added to the remaining iodine monochloride to release iodine: ICL + 2ki → KCL + I 2 . The remaining iodine reacts with starch to form a dark blue compound.
The sodium thiosulfal solution at a known concentration is then slowly added. Iodine reacts with it to form colorless ions i
Animal and vegetable fats and oils are a mixture of triglycerides. Fat or oil with a high content of unsaturated triglycerides will have a high iodine value. Many vegetable oils are rich nand unsaturated triglycerides. For example, sunflower oil has a iodine value of 110-143, compared to 35-48 for typical animal fat. Coconut oil, on the other hand, is highly saturated, with iodine only 6-11.
There are two more numbers that can be associated with fats and oils. The number of saponifications is an indication of the average molecular weight of fat and is determined by its division into glycerol and salt of fatty acids by treatment of strong alkalia. The acid number shows how much free fatty acids contain fat and is estimated from the amount of alkalia needed to neutralize it.