Lab 7 Soapmaking and Biodiesel Fuels Laboratory Goals The goals of this lab are Make soap using sodium hydroxide and an oil Test some properties of synthesized soap Design a synthesis for biodiesel fuel from vegetable oil Answer the question the lab as a group decides upon Learn the role of reaction conditions on the product distribution Safety Notes The sodium hydroxide solution used in this lab is extremely concentrated Be sure to avoid any contact with skin and especially eyes as it can cause serious burns All spills MUST be immediately reported to the LA and cleaned Introduction This lab is schedule for three weeks The first week will focus on making soap and also the development of a testable hypothesis regarding the synthesis of biodiesel fuel Week two and three will focus on implementation of a student designed project to test the synthesis of biodiesel Soapmaking The process of soap making goes far back in history Most people who have made soap throughout the centuries have had no idea what is occurring they simply made soap through trial and error lots of luck and governing superstitions The process similar to what we will be doing in lab involved combining some form of fat with an alkali basic material Most commonly the alkali was in the form of potash and pearlash which contain KOH Potash and pearlash soaps were used by everyone from the reigning monarchs to the peasant or cottager who made their own soap from the waste fats and ashes they saved The First Soap It is recorded that the Babylonians were making soap around 2800 B C and that it was known to the Phoenicians around 600 B C These early references to soap and soapmaking were apropos the use of soap in the cleaning of textile fibers such as wool and cotton in preparation for weaving into cloth The Romans and Celtics The first definite and tangible proofs of soap making are found in the history of ancient Rome Pliny the Roman historian described soap being made from goat s tallow and 7 1 causticized wood ashes He also wrote of common salt being added to make the soap hard The ruins at Pompeii revealed a soap factory complete with finished bars While the Romans are well known for their public baths generally soap was not used for personal hygiene To clean the body the Greeks and later the Romans would rub the body with olive oil and sand A scraper called a strigil was then used to scrape off the sand and olive oil also removing dirt grease and dead cells from the skin which was left clean Afterwards the skin was rubbed down with salves prepared from herbs Throughout history people have taken baths in a variety of bathing mediums with herbs and other ostensibly beneficial additives It is well known that Cleopatra who captivated the leaders of the Roman world attributed her beauty to her baths in mare s milk During the early centuries of the common era soap was used by physicians in the treatment of disease Galen a second century physician recommended bathing with soap for the amelioration of some skin conditions Soap for personal cleansing became popular during the later centuries of the Roman era The Celtic peoples are also though by some historians to have discovered soap making their soaps were used for bathing and washing Perhaps due to increased contact with the Celtics by the Romans using soap for personal cleansing became popular There is an interesting legend surrounding the discovery of soap making This legend accords the discovery of soap to the Romans so it might have been fabricated to confront the Celtic claim to soap making Probably both of these inventive peoples discovered soap making independently The legend asserts that soap was first discovered by women washing clothes along the Tiber River at the bottom of Sapo Hill The women noticed their wash became cleaner with far less effort at that particular location What was happening The ashes and the grease of animals from the sacrificial fires of the temples situated on the top of Sapo Hill mixed with the rain the resulting soap which ran down the slope in the streams of rain water give the women a wash day bonus One can see at a glance that saponification the chemical name for the soap making reaction bears the name of that hill in Rome long ago which caused one washer women to comment to another My wash is cleaner than yours The Chemistry of Soapmaking As stated earlier the chemistry behind soap making was not understood for many years It is now known that saponification of soaps proceeds by the conversion of the triglycerides which are the components of fats and oils to fatty acid salts and glycerol as show in Figure 1 The R groups in the figure represent long carbon chains with the accompanying hydrogens For each specific triglyceride these specific R groups can be determined For example tristearin gives the reaction shown in Figure 2 7 2 O CH2OH CH2OCR CHOCR O O 3 NaOH 3 NaOCR CHOH fatty acid salt soap O CH2OH CH2OCR glycerol a triglyceride in a fat or oil Figure 1 Reaction of a triglyceide with sodium hydroxide O CH2OH CH2OC CH2 16CH3 O O CHOC CH2 16CH3 3 NaOH 3 NaOC CH2 16 CH3 CHOH Sodium stearate O CH2OH CH2OC CH2 16CH3 glycerol tristearin Figure 2 Reaction of tristearin with sodium hydroxide Typically fats and oils have more than one different R group in the same molecule so a variety of sodium salts are produced In order to separate out the salts from the rest of the reaction products a saturated NaCl solution is added This forces the soap to coagulate without dissolving in the water It can then be collected by filtration and washed to remove the excess base Table 1 lists the different carboxylic acids that originally reacted with glycerol to yield the triglycerides found in the fats and oils It shows the relative ratio of the acids for a variety of 7 3 Table 1 Percent by weight of total fatty acids Mono unsat Saturated Oil or Fat Unsat Linoleic Alpha Sat Capric Lauric Myristic Palmitic Stearic Oleic Acid Linolenic Acid Acid Acid Acid Acid Acid ratio 6 Acid 3 C10 0 C12 0 C14 0 C16 0 C18 0 C18 1 C18 2 C18 3 Almond Oil 9 7 Beef Tallow 0 9 Butterfat cow 0 5 3 Butterfat goat 0 5 7 Butterfat human 1 0 2 Canola Oil Poly unsaturated 7 2 69 17 3 24 19 43 3 1 3 11 27 12 29 2 1 3 9 25 12 27 3 1 5 8 25 8 35 9 1 15 7 4 2 62 22 10 Cocoa Butter 0 6 25 38 32 3 Cod Liver Oil 2 9 8 17 22 5 Coconut Oil 0 1 6 47 18 9 3 6 2 Corn Oil Maize Oil 6 7 11 2 28 58 1 Cottonseed Oil 2 8 1 22 3 19 54 1 Flaxseed Oil 9 0 3 7 21 16 53 Grape seed Oil …