Preparation and Properties of soap

Materials and Apparatus: Olive oil, 95% ethanol, beaker, 50% sodium hydroxide solution, Boucher alter, hot plate, salt solution, magnetic stirrer, filter funnel, glass rod, filter paper, weighing balance, watch glass and measuring cylinder. From the diagram above, we can clearly see that the ionic (highly polar and charges) natures of salts makes them soluble in water. However, the non- polar hydrocarbon (aliphatic) tail of the soap molecules would cause them to be miscible with non-polar substances and enable them to dissolve in water.Normally, solid soaps are consist of sodium salts of fatty acids and liquid soaps consist of potassium salts of fatty acids. Soap can be prepared by a process known as specification. Historically, soaps were made by boiling the fat of animal, lye and in a aqueous Noah and KOCH solution containing potash. Of course, this was done long time ago before anyone had any idea of understanding the chemical transformations. Now, we know that this process is a r eaction of esters with a strong base such as KOCH or Noah.The esters, triglycerides are the main constituents of vegetable oil and animal fats. The triglyceride is a trim-ester come along with 3 long fatty acid hydrocarbon chain. When triglyceride reacts with 3 equivalents strong aqueous base solution such as Noah or KOCH, the three ester bonds are hydroxide to yield 3 fatty acid salts (soap molecules) and one glycerol. The specification can also be called â€Å"base hydrolysis†. Industrially, soap is made by reaction of Noah together with vegetable fat. It is crucial to utilize enough Noah to make sure a complete specification Of triglycerides.If there is insufficient base, time and heat provided, then the result would be incomplete specification and the soap product can be very brittle. If the specification is complete, Nasal is added to precipitate the soap. The aqueous portion is decanted off. The remaining substance would be crude soap which contains some impurities such as Nasal, Noah or glycerol. In the lab, we do not have enough time to purify the crude soap. This purification would consist of re-dissolving the soap in boiling water and then cooling and precipitating again by adding Nasal.The soap in the experiment would be made out from olive oil, the chemical structure of olive oil (C52H9606) would be like this: Procedure: 1 . About ml Olive Oil was added to a mall_ beaker and dissolved it in ml of 95% ethanol. Excessive oil was not used to avoid additional ethanol to dissolve it. 2. When the olive oil was completely dissolved, the beaker was put on the hot plate and the temperature was maintained to about ICC. The flask was swirled to mix the solution. Next, ml of 50% Noah solution was poured down the glass-stirring rod intro the oil solution.A small amount of the Noah solution was trickled down the rod very slowly and then stopped to stir. Then, a little more Noah was trickled in. The Noah solution was not poured into the oil too quickly. Th is was due to the reason that pouring the Noah solution too quickly Will cause the oil to separate from the Noah solution, and the final product would be failure. The mixture was stirred until it thickened. We wanted to avoid getting a mixture with 2 distinct layers Noah solution on the bottom and oil on the top.When 2 distinct layers are forming, it was stirred vigorously using magnetic stirrer until the liquids are well stirred. 3. A small watch glass was placed over the mouth of the flask to minimize evaporation of the alcohol. 4. The oil-alcoholic-Noah solution was allowed to boil for at least 30 minutes. The undisclosed fat in the flask and solved by adding a little more ethanol and stirred. The temperature was kept just hot enough to have controlled boiling of the fat solution. 5. While the specification proceeded, a salt solution was prepared by completely dissolving go Nasal in 1 00 ml distilled water in a mall beaker.After he salt was completely dissolved, about half of thi s salt solution was transferred to another beaker and both beakers of salt solution was placed on ice to cool them. 6. After 30 minutes, the fat solution was tested to see if specification was completed by placing a few drops of the solution in a test tube of distilled eater. When the fat droplets floated to the top, the specification was not completed and allowed it to boil for an additional 10 minutes. 7. When the specification was completed, the hot reaction mixture was poured carefully into one beaker of salt solution and stirred for a minute or two.