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Such a triglyceride has a high iodine value (approx. 119). Below, the reaction product after the addition of four equivalents of iodine or bromine to the four C=C double bonds of the unsaturated fatty acid residues. The determination of iodine value is a particular example of iodometry. A solution of iodine I 2 is yellow/brown in color.
These iodine compounds are hypervalent because the iodine atom formally contains in its valence shell more than the 8 electrons required for the octet rule. Hypervalent iodine oxyanions are known for oxidation states +1, +3, +5, and +7; organic analogues of these moieties are known for each oxidation state except +7.
The bromine number is similar to the iodine number, which is a similar technique used in evaluating the unsaturation of fats and fatty acids. Iodine is less reactive toward the tri- and tetra-substituted double bonds, [2] found in petroleum-derived samples. The C=C double bonds in fats and fatty acids are exclusively disubstituted.
The Reichert value is an indicator of how much volatile fatty acid can be extracted from a particular fat or oil through saponification. It is equal to the number of millilitres of 0.1 normal hydroxide solution necessary for the neutralization of the water-soluble volatile fatty acids distilled and filtered from 5 grams of a given saponified fat.
The iodine value is a way to determine the presence of unsaturation quantitatively. The bromine test is a simple qualitative test. Modern spectroscopic methods (e.g. NMR and infrared spectroscopy) are better at determining the structural features and identity of unknown compounds.
Example of saponification reaction of a triglyceride molecule (left) with potassium hydroxide (KOH) yielding glycerol (purple) and salts of fatty acids ().. Saponification value or saponification number (SV or SN) represents the number of milligrams of potassium hydroxide (KOH) or sodium hydroxide (NaOH) required to saponify one gram of fat under the conditions specified.
For hydrocarbons, the DBE (or IHD) tells us the number of rings and/or extra bonds in a non-saturated structure, which equals the number of hydrogen pairs that are required to make the structure saturated, simply because joining two elements to form a ring or adding one extra bond (e.g., a single bond changed to a double bond) in a structure reduces the need for two H's.
In chemistry, acid value (AV, acid number, neutralization number or acidity) is a number used to quantify the acidity of a given chemical substance. It is the quantity of base (usually potassium hydroxide (KOH)), expressed as milligrams of KOH required to neutralize the acidic constituents in 1 gram of a sample.