Colorimetric and potentiometric determination of acid numbers of vegetable and marine oils
Summary A discussion is presented of present official methods of determining the acid number of oils. A colorimetric method is presented for the determination of acid numbers of marine and vegetable oils and related products. It involves the use of alcoholic KOH, phenolphthalein, and a titration sol...
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| Published in: | Journal of the American Oil Chemists' Society Vol. 25; no. 6; pp. 203 - 206 |
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| Main Authors: | , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Berlin/Heidelberg
Springer‐Verlag
01-06-1948
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| Online Access: | Get full text |
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| Summary: | Summary
A discussion is presented of present official methods of determining the acid number of oils. A colorimetric method is presented for the determination of acid numbers of marine and vegetable oils and related products. It involves the use of alcoholic KOH, phenolphthalein, and a titration solvent consisting of 49.5% anhydrous isopropanol. 50% benzene, and 0.5% water. Most oils are completely soluble in the titration solvent, thus avoiding the disadvantages of two phase systems and of heating the oil. It compares satisfactorily with present official methods.
A potentiometric method which is at present an A.S.T.M. Standard Method for petroleum products is discussed. It has proved to be satisfactory for use with marine and vegetable oils.
A close correspondence has been shown with a number of different oils between acid numbers obtained colorimetrically and potentiometrically. This makes it possible to compare directly results obtained by the two methods. |
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| Bibliography: | Communication No. 124 from the Laboratories of Distillation Products, Inc., Rochester, N. Y. |
| ISSN: | 0003-021X 1558-9331 |
| DOI: | 10.1007/BF02645891 |