Abstract: . . .  effect is remarkable. Although it is not obvious from the structures shown in Table 1, molecular models show the elaidic acid molecules, and other trans fatty acids, can be extended in a more linear fashion more early, and hence be fit into a crystal lattice more easily, than cis fatty acids. In other words, trans fatty acids are less lumpy than cis fatty acids. These melting points are of more than academic interest. Nature chooses cis double- bonded fatty acids precisely because their melting points are lowest. The bilayers in biological membranes must be liquid, for one thing (they are made of phospholipids, which contain fatty acids). For another, many clinical studies have shown a correlation between the melting points of fatty acids consumed and hardening of the arteries. Saturated fatty acids appear to be a menace. However, trans fatty acids appear to be equally menacing. They are absent in natural fatty acids, but are produced by catalytic hydrogenation of plant oils. That is, when cis double bonds are exposed to a metallic catalyst in a hydrogen atmosphere, hydrogen is added to some of the double bonds but other undergo cis-trans isomerization instead of addition. The effect of saturated and trans fatty acids upon the formation of arterial plaque is clearly related to their physical properties. The trends in melting points seen in the fatty acids are reflected in the melting points of  . . .
. . .  on its side, and rotate it to spread the liquid over the inside surface of the flask. Finally, release the vacuum line, and cool the flask in ice. II. Characterizing the product Read Sorrell pp. 691 708 and Mohrig pp. 610-627 on proton NMR. A. Melting point Determine the melting point of the hydrogenated olive oil by placing it in a small disposable test tube in water at various temperatures. The approach is necessary because the melting point is low, and because it is impossible to get the material in a capillary tube. B. Spectroscopic analysis Infrared and elementary proton NMR will be used to explain the observed melting point. The details will be made more clear in a handout. For now, try to digest the rudiments of NMR.  . . .
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