Abstract: . . .  made by catalytic cracking of crude oil, and every drop of grease on your french fries and in those little tubs of imitation butter comes from vegetable oil which has spent time adsorbed to a metallic catalyst in an atmosphere of pure hydrogen. Catalytic reduction, together with a little synthetic yellow dye, converts soybean and corn oil into a semi-solid substance called margarine, which is actually eaten by some people who have not discovered olive oil. Furthermore, as we shall see, partially hydrogenating vegetable oil not only solidifies it, but also slows oxidation and hence reduces the tendency to become rancid. At the same time, popular diet gurus, as well as trained physicians who actually understand what they are talking about, point out that there is a dark side to hydrogenated vegetable oil. Hydrogenation increases the content of saturated fatty acids and trans fatty acids, both of which contribute to the formation of 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 tristearin, is a fat (mp 72 C) containing three molecules of stearic acid: H 2 C 0 C CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 H C O C CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 H 2 C O C CH 2 CH 2 CH 2  . . .
--3000,1,1500,3091,19438