Oleic add

Parathasarathy, S., Khoo, J.C., Miller, E., Barnett, J., Witztum, J.L. and Steinberg, D. (1990). Low density lipoprotein rich in oleic add is protective against oxidative modification implica-tiorrs for dietary prevention of atherosderosis. Proc. Nad Acad. Sci. USA 87, 3894-3898. 

The more eflicienl defoaming mechanism of spreading involves transpon of underlying liquid so that the liquid is replaced by a film of deloumcr that docs not support foam. A drop of oleic add added to water spreads at a velocity of 30 miles (48.2 kilometers) per hour. The mechanical shock to a film by such a defoamer may be considerable. In addition lo the foam-destroying aspect, spreading is also of value as a defoamer-dispersion method, particularly in viscous or poorly stirred systems. 

Oleic acid may be obtained from glycerol trioleate, present in many liquid vegetable and animal nondrying oils, such as olive, cottonseed, lard, by hydrolysis. The crude oleic acid after separation of the water solution of glycerol is cooled to fractionally crystallize the stearic and palmitic acids, which are then separated by filtration, and fractional distillation under diminished pressure. Oleic acid reacts with lead oxide to form lead oleate, which is soluble in ether, whereas lead stearate or palmitaie is insoluble, prom lead oleate oleic add may be obtained by treatment with IL 5 (lead sulfide, insoluble solid, formed). With sodium oleate, a soap is formed. Most soaps are mixtures of sodium stearate, palmitate. and oleate. 

Representative esters of oleic add are methyl oleate, C17H33COOCH3, bp 190 C at 10 millimeters pressure ethyl oleate. CnH COOCiHs, bp 205°C at 10 millimeters pressure glyceryl trioleate (triolein), (jj, bp 240°C at 18 millimeters pressure. 

Oleic acid is used in the preparation of metallic oleates, such as aluminum oleate for thickening lubricating oils, for water-proofing materials, and for varnish dryers. The glyceryl ester of oleic add is one of the constituents of many vegetable and animal oils and tats. 

Palmitic acid is present as cetyl ester in spermaceti from which, by hydrolysis, the acid may be obtained it is present in bee s wax as the mehssic ester and in most vegetable and animal oils and fats, in greater or lesser amounts, as glyceryl tripalmitate or as mixed esters, along with stearic and oleic adds, Palmitic acid is separated from stearic and oleic acids by fractional vacuum distillation and by fractional crystallization. With NaOH, palmitic add forms sodium palmitate, a soap, Most soaps are mixtures of sodium stearate, palmitate, and oleate. 

Oleate. Sodium oleate, [CAS 143-19-1], NaCi H33 02, white solid, soluble, froth or foam upon shaking the H40 solution (soap), formed by reaction of NaOH and oleic add (in alcoholic solution) and evaporating. Used as a source of oleate. 

Fig.4.16. Separation of some 2-naphthacyl esters of fatty adds. A, C, adds B, C adds. Peaks 1 = oleic add 2 = linoleic add 3 a-Unolenic add 4 = 7-linolenic add 5 = dihomo-7-linolenic add 6 = arachidonic add 7 = 2-naphthacyl bromide. (From ref. 40 with permission of the American Chemical Society, Washington.)...

H20-insol soap 2.8, and product of reaction betw oleic add and aniline 1.2%. It is blended under water and the resulting slurry is centrifuged, passed thru endless screw press and then thru heated rolls. The resulting sheets are cut into strips, or passed thru press to form cords. The insol soap consists of Mg oleate 70, Ca oleate 20 Ca stearate 10%... 

Pelargonic acid has been prepared by the oxidation of oleic add 1 and by hydrolysis of octyl cyanide or heptylacetoacetic ester.3... 

When compared to 12 0, 14 0, and 16 0, oleic acid (18 1) or linoleic acid (18 2) provokes a drop in LDl- CholesteroI of about 15%, When directly comparing monounsaturated fatty acids with FUFAs, one finds that ntonounsaturated fatty acids seem to raise plasma TG levels, A slight increase in plasma TG may occur with the oleic add. in addition, PUFAs seem to be more consistent at raising HDLoleic acid. In these respects PUFAs may be more desirable than monounsaturated fattv adds (Kris-Etherton and Yu, 1997),... 

A mechanism has been proposed for the influence of various dietary fatty acids on plasma LDL-cholesterol levels. The scenario where oleic add (18 1) can provoke a decline in LDL-cholesterol is as follows (Woollett and Dietschy, 1994 Rumsey et al, 1995) ... 

The RDA for the essential fatty acids is 1 to 2% of total energy intake. Generally, between 5 and 10% of our energy intake consists of EFAs. Because of our ample intake of fat, a deficiency in EFAs is quite rare. The biochemical steps in the modification of nonessential fatty acids, such as oleic add, and essential fatty adds (linoleic add and linolenic acid) are generally the same. These steps include elongation and desaturation. Modification of fatty adds by their repeated desatu-... 

The saturated chain is added first, at Cl of glyceryl phosphate. The reagent is a thiol ester called acyl coenzyme A, whose full structure you will see in the next chapter. This reaction occurs by simple nucleophilic attack on the carbonyl group of the thiol ester followed by loss of the better leaving group, the thlolate anion. Then the process is repeated at the second OH group where an unsaturated fatty acid, perhaps oleic add, is added by the same mechanism. 

Name Oleic add, decyl ester Sample preparation Capillary film, sodium chloride cell... 

---