Abstract: . . .  arterioscleroic plaque, with subsequent infarctions and heart attack. Apparently, cis-trans isomerization, which is a side effect of catalytic hydrogenation, can kill you. In this experiment, we will hydrogenate olive oil, examine the properties of the product, and use infrared and nuclear magnetic resonance spectroscopy to explain the results. First, however, a brief discussion of fats and oils will be helpful. Fats and oils Catalytic Hydrogenation and Arteriosclerosis Page 2 2 Fats and oils are triglycerides, which consist of glycerol molecules esterified with three fatty acids. Fatty acids are essentially long hydrocarbon chains terminating in a carboxyl group. Stearic acid (18 carbons, saturated) is an example: Triglycerides are called fats if they are oils at (low melting point) and fats if they are solid (higher melting point). For instance, glyceryl tristearate, also called . . .
. . .  plant oils. It furnishes low- melting-point fatty acids, which do not produce arterial plaque, yet they cannot oxidize because they are monounsaturated. There are not trans fatty acids, and almost no unsaturated ones. THE EXPERIMENT We will use olive oil as a model compound to illustrate the effects of catalytic hydrogenation, using palladium as the catalyst. Its molecular simplicity (monounsaturated fatty acids) makes the calculation of the fatty acid distribution straightforward. Although hydrogenation is usually done with hydrogen gas, we will use transfer hydrogenation, where hydrogen atoms are catalytically transferred from cyclohexene to the fatty acids in the triglyceride. The major component in olive oil is glyceryl trioleate. If there are no complications and the reaction goes to completion, the product is glyceryl tristearate: Page 7 7 H 2 C O C O (CH  . . .
. . .  before placing the pipet in the tube and conical flask, and approach the liquid surface gingerly. Too much gas will blow the liquid out of the flask into the tube, and you will have to rinse it down with cyclohexane and start over. Continue the evaporation until bout 0.5 mL of viscous oil remains (the initial volume of the olive oil before the cyclohexene was added). Finish the evaporation in vacuo. Almost all the solvent must be evaporated before taking this step. If it is not, the liquid may boil excessively when the vacuum is applied. Attach the Hickman still to the flask, seal the top of the still with a septum, and connect the side arm of the still of the vacuum line. Used this way, the still is simply a way to connect the flask to the vacuum line. Turn on the vacuum, and hold the flask in boiling water for 20 minutes to remove the last traces of solvent. Remove the flask from the water frequently, turn it on its side, and rotate it to spread . . .
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