Saponification of Triglycerides Lab Report Example | Topics and Well Written Essays - 1500 words

Saponification of Triglycerides - Lab Report Example In this process the triglyceride is reacted with a strong base such as sodium or potassium hydroxide to produce glycerol and fatty acid salts (Whitten et al., 2007). The saponification of glyceryl tristearate is illustrated in Figure 1. The commonest soaps are the fatty-acid salts of sodium and potassium. Hard soaps are sodium salts while soft soaps are potassium salts. The fatty-acid salts of ammonium are also sometimes used for cleansing. Only a few other soaps are of practical importance, for example lead soaps which are used in medicinal plasters, zinc soaps which are used in ointments, and aluminum soaps which are used in waterproofing. Very few of the salts of fatty acids have the properties of common soap. Most of them are but slightly soluble in water, and therefore do not yield suds and have little or no detergent (i.e., cleansing) action. All are nevertheless termed soaps by chemists (Lewkowitsch, 1904). The saponification number (S) is the number of milligrams of potassium hydroxide required to convert one gram of the fat completely into glycerine and potassium soap. It gives information concerning the character of the fatty acids of the fat and in particular concerning the solubility of their soaps in water. Table 1 lists the saponification number of the common fats and oils. Table 1 shows that butter ranks with palm kernel oil and coconut oil as having a very high saponification number. ... Mutton tallow 192 - 195.5 Menhaden oil 190.6 Peanut oil (arachis) 190 - 196 Corn oil 188 - 193 Horse oil 195 - 197 Olive oil 185 - 196 Beef tallow 193.2 - 200 Soy bean oil 193 Palm oil 196 - 205 Cacao butter 193.55 Butter 220 - 233 Linseed oil 192 - 195 Palm kernel oil 242 - 250 Cottonseed oil 193 - 195 Coconut oil 246 - 260 Lard 195.4 (Lewkowitsch, 1904: 400) Table 1 shows that butter ranks with palm kernel oil and coconut oil as having a very high saponification number. This is due to the fact that its triglycerides contain appreciable quantities of fatty acids (myristic acid and small quantities of lauric acid) which when they form soap combine with relatively more sodium or potassium than the more common acids of fats. These acids occur in undecomposed butter in chemical combination as triglycerides. Their sodium or potassium soaps are quite soluble in water. The high saponification number of coconut oil and palm kernel oil is due to the large proportion of fatty acids (lauric acid and myristic acid) that they contain. In this laboratory exercise, saponification as the hydrolysis in basic solution of fats and oils to produce glycerol and salts of fatty acids, and determination of saponification number of sample fat and oil were evaluated. II. Method Triglyceride (2 g) was accurately weighed and was placed in a dry round bottom flask. The prepared ethanolic potassium hydroxide solution (50 cm3) was added to the flask using a pipette. Few anti bumping granules were added to the stirring solution. After setting up the reflux condenser, the solution was boiled for at least 30 minutes. A blank experiment with identical volume as the sample solution was also carried out. After refluxing, the solution was allowed to cool. After cooling, a few drops of