Iodine value means the “g” value of halogen which adhere to g of methods such as Hanus method and Wijs method for Iodine value. The processors of oil and fat are in need of a quick determination method of iodine value of oils and fats especially in case of checking the degree of. This test method covers the determination of the iodine value of fats and iodine value of fats and oils that do not contain conjugated 3 Wijs Solution ( Iodine Monochloride Solution) may be purchased commercially. 1.
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On the Determination of Iodine Value by the Wijs’ Method
The Wijs method as the standard for iodine absorption. Saturated fatty acids will not give the halogenation vwlue. Unsaturated fatty acids can be converted into saturated by the process of hydrogenation. Ullmann’s Encyclopedia of Industrial Chemistry.
So handle the reagent with gloves. Fatty acids are long chain hydrocarbons with carboxyl groups COOH groups. Previous Article Next Article. This reaction must be carried out in the dark, since the formation of bromine radicals is suppressed by light. Starch is used as the indicator for this reaction so that the liberated iodine will react with wija to give purple coloured product and thus the endpoint can be observed.
Jump to site search. Triglycerides are made up of three fatty acids linked to glycerol by fatty acyl esters.
Hoffman and Green modified the Wijs’ method by employing mercuric acetate as catalyst and made it possible to determine the iodine value of a methood in ten minutes or so. Jump to main content. This quick Wijs’ method gives almost equivalent value of Hoffman’s although it tends to give less value than that of the Wijs’ method.
For reproduction of material from NJC: Mercuric acetate, however, cannot be empolyed now iodune the reaction solution is hard to meet the regulation of water pollution and its disposal has become difficult. December 20, received: If you are the author of this article you do not need to formally request permission to reproduce figures, diagrams etc.
They are likely to exists as liquids at room temperature. This would lead to undesirable side reactions, and thus falsifying a result consumption of bromine.
Iodine value – Wikipedia
If you are the author of this article you still need to obtain permission to reproduce the whole article in a third party publication with the exception of reproduction of the whole article in a thesis or dissertation. Reproduced material should be attributed as follows: Unsaturated fatty acids contain double bonds between the carbon atom in addition to the single bonds present in the fatty acid chain.
If you are not the author of this article and you wish to reproduce material from it in a third party non-RSC publication you must formally request permission using Copyright Clearance Center. Bromination of the double bonds in the dark, reducing the excess bromine with iodidebacktitration of iodine with thiosulfate.
After the reaction is complete, the amount of iodine that has reacted is determined by adding a solution of potassium iodide to the reaction product.
Information about reproducing material from RSC articles with different licences is available on our Permission Requests page. Back to tab navigation Download options Please wait On the other hand, linseed oil is highly unsaturatedwhich makes it a drying oilwell suited for making oil paints.
Journal home Journal issue About the journal. This causes the remaining unreacted ICl to form molecular iodine. Back to tab navigation Fetching data from CrossRef. To determine the iodine value of fats and oils and thus estimate the unsaturation of the fats and oils.
XX is the XXth reference in the list of references. Wheat germ oil . Depending upon the degree of unsaturation, the fatty acids can combine with oxygen or halogens to form saturated fatty acids. Fetching data from CrossRef.