Appendix Oleic Acid

Free Fatty Acids (as oleic acid) Determine as directed under Free Fatty Acids, Appendix VII, using 28.2 as the equivalence factor (e) in the calculation for oleic acid. Titrate with the appropriate normality of sodium hydroxide solution, shaking vigorously, to the first permanent pink color of the same intensity as that of the neutralized alcohol (if the sample color interferes, titrate to a pH of 8.5, determined with a suitable instrument). 

Free Fatty Acids (as oleic acid) Determine as directed under Free Fatty Acids, Appendix VII, using the following equivalence factor (e) in the formula given in the procedure ... 

Oleic Acid Isolate the fatty acids as directed under Laurie Acid in the monograph for Polysorbate 20, and determine the weight of the acid. With the product so obtained, determine the acid value (between 193 and 206) as directed in Method I under Acid Value, Appendix VII. Similarly determine the iodine value (between 80 and 92) as directed under Iodine Value, Appendix VII. 

Two fatty acids abundant in our diets are the 18-carbon saturated stearic acid and the 18-carbon unsaturated oleic acid. How is the structure of the molecule affected by the presence of a double bond Refer to Table C-1 in Appendix C for a key to atom color conventions. 

Weickeb and collaborators [182] have studied the hpids in normal and in strongly chylous duodenal secretions obtained from a patient with exsudative enteropathy by means of a double baUoon tube principaUy neutral fats along with phospholipids and cholesterol could be detected with the help of TLC. Oleic acid, labehed with was introduced into the jejunum and 15 min later it was already possible with the help of TLC to detect active phosphohpids in the duodenal juice. With two healthy subjects, this increase in activity in the duodenal secretion took place only after 2 hours and was much less than with the patients suffering from enteropathy. Williams and co-workers [192] have investigated the hpid composition of faeces and faecohths from the appendix and foimd chiefly free fatty acids. The faecal sterols are mentioned below in section 4,... 

Although Sabatier and Senderens had hydrogenated oleic acid vapor to produce stearic acid, they did not extend this work themselves. The appendix to Chapters 11 and 12 in their book describes early work to about 1916, by others who used nickel and palladium catalysts. They described the use of nickel supported on pumice, kieselguhr, asbestos, and wood charcoal. ... 

Liu (2007) introduced another method called soap extraction to quantify acid number. Because the anionic surfactant can be accurately determined by potentiometric titration (see Appendix A in Liu, 2007) with benzethonium chloride (hyamine 1622), it is reasonable to use this method to find the natural soap amount. Because this potentiometric titration is for the aqueous phase, the soap should be extracted into the aqueous phase as the first step. As an anionic surfactant, the natural soap may stay in the oleic phase and form Winsor type 11 microemulsion when the electrolyte strength is high. To extract the soap into the aqueous phase, NaOH is used to keep the pH high with low electrolyte strength. Also, isopropyl alcohol is added to make the system hydrophilic so that soap will partition into the aqueous phase. 

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