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It is an indication of a fat’s potential to be oxidized as it measures the reaction of iodine with the double bonds of unsaturated fatty acids 2. Chemical name: Wijs solution Chemical synonyms: Iodine monochloride solution; Iodine according to Wijs for the iodine value determination; Chloroiodide solution; Wijs solution Product Brand: Analytical Density (g/cm3): 1.06 Flash Point (°C): 40 °C Molecular weight: 162.36 Molecular…
Iodine value, also called Iodine Number, in analytical chemistry, measure of the degree of unsaturation of an oil, fat, or wax; the amount of iodine, in grams, that is taken up by 100 grams of the oil, fat, or wax.
Hoffman and Green modified the Wijs' method by employing mercuric acetate as catalyst and made it possible to determine the iodine value of a sample in ten minutes or so.
Add 10 ml of potassium iodide solution and 100 ml of water and titrate with 0.1 M sodium thiosulphate using starch solution, added towards the end of the titration, as indicator.
Mercuric acetate, however, cannot be empolyed now because the reaction solution is hard to meet the regulation of water pollution and its disposal has become difficult. ;��t�8���Ξ��[������:=Ȣ�xҿ���34ʹ+�t'�ǭDG,�h�:o;vǁ裴״�f�HԈ%����1V>o�ݷ?���,ݶ:^�}q��Qz���I��s�G��I�$�.z2��k�{���d;f�����B��Q�4���H���\C��(&B��GX�DR��jN��hËiڪ�n%p�3�!1��Цہ�� 6L��gb�24;f�Wm�����o��H�5�Y��D2fW���KXV¦(m�D�XR7 -�����5�w��95cZRstXJ��Z��a2��n���o����8�y��9Z�m���c
Wijs solution is a solution of containing iodochloride in glacial acetic acid.
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The result is expressed as g of iodine (I2) per 100 g of sample; the molar weight of I2 is 253.8 g/mol. Iodine value means the “g” value of halogen which adhere to g of methods such as Hanus method and Wijs method for Iodine value. Saturated oils, fats, and waxes take up no iodine; therefore their iodine value is zero; but unsaturated oils, fats, and waxes take up iodine.
Since fats with a greater number of double bonds provide more sites for oxidation, the iodine value of a fat helps predict fat stability 2. IODINE NUMBER (Wijs Method) PRINCIPLE The vegetable oil sample is reacted with an excess of iodine monochloride solution (Wijs reagent) under controlled conditions.
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. The iodine value of animal and vegetable fats and oils measures the amount of -C=C- (double bonds) present in the product.
Add slowly from a burette 25.0 ml of iodine monobromide solution, insert the stopper, allow to stand in the dark for 30 minutes, unless otherwise specified in the monograph, shaking frequently.
History at your fingertips 5 0 obj Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Iodine value refers to the percentage of iodine absorbed by a substance such as a fat or oil 1.
Semidrying oils, such as soybean oil, have intermediate iodine values (about 130). <> This test method covers the determination of the iodine value of fats and iodine value of fats and oils that … Case study: Peruvian Anchovy - Why feed, not food?
Our editors will review what you’ve submitted and determine whether to revise the article.Drying oils used in the paint and varnish industry have relatively high iodine values (about 190).
Nondrying oils, such as stream Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox.