 Welcome to the biodiesel production and analysis lab video. Let's start with some background on diesel. The first diesel engine was developed in 1893 and used peanut oil as feedstock, however with the introduction of refined petroleum diesel prepared from crude oil, oil from seed plants fell out of favor. More recent concerns over continued availability of fossil fuels, as well as the rise of greenhouse gases, have renewed interest in bio-renewable resources. Now let's discuss what makes diesel different from gasoline. First, the mixture of hydrocarbons is different. While diesel contains a mixture of hydrocarbons ranging from 8 to 21 carbons long, gasoline is a mixture of largely 8 carbon chains. Due to its longer carbon chains, diesel has a lower flammability and explosivity when compared to gasoline. Diesel must also be distilled at a much higher temperature. Lastly, gasoline engines require a spark plug to detonate, whereas diesel engines use high pressure to generate high temperatures, which results in fuel detonation. In this lab, you will make biodiesel from canola or soybean oil. Gales and fats from seed plants are mainly in the form of triglycerides. Triglycerides are esters containing three fatty acids conjugated to a glycerol molecule. Triglycerides cannot be used directly as fuel, however the bonds to glycerol can be cleaved to produce a glycerol molecule in three fatty acids. Free fatty acids, however, are also problematic because they readily undergo ionization to form salts. These salts are typically solids under operating conditions resulting in buildup in the engine. We can use a reaction called transesterification to solve this problem. In this reaction, which is catalyzed by sodium hydroxide, the triglyceride reacts with an alcohol to form methyl ester fatty acids and glycerol. Methyl ester fatty acids will not ionize and will remain liquid until combusted. Now let's review the procedure. First you will use seed oils to synthesize crude biodiesel. Start by adding 14 ml of methanol to a 50 ml beaker with a stir bar. Place the flask on a stir plate. Set the stir speed so that it stirs vigorously but doesn't splash. Slowly add 0.5 g of sodium hydroxide to the mixture and wait for it to completely dissolve. At this point, sodium methoxide has formed. Proceed cautiously. Sodium methoxide is a strong base. Next pour 50 ml of your oil into a 250 ml beaker. Use a magnetic stirring hot plate to warm it to 50 degrees Celsius while stirring at medium speed. Once the oil has reached 50 degrees, turn off the heat. Next slowly add the sodium methoxide to the warm oil while stirring. The solution will become cloudy. Stir the reaction for 20 minutes after the last drop of sodium methoxide is added. Your instructor will show you how to properly operate the centrifuge. You should centrifuge the vials for 2 minutes at 4000 rpm. After centrifugation, the vials will have two layers. Carefully pour the liquid layer into another tube and discard the solid layer. Next use a graduated cylinder to find the mass and volume of your product. To do this, place a graduated cylinder on a scale and zero the scale. Pour your product into the graduated cylinder and place it back on the scale. The mass displayed on the scale is the mass of your product. You can use this value to calculate your percentage yield. The next step is to purify the biodiesel fuel. To do this, you will use an aqueous phase partitioning process. This method works because the biodiesel component is not water soluble, but many of the contaminants to be removed are. First, add your crude biodiesel to a 150 ml beaker. Add 5 ml of .1 molar acetic acid and gently swirl the flask. After a minute of swirling, let it settle for a few minutes in order for two layers to develop. Tip the flask at a 45 degree angle and collect and discard the bottom layer. Repeat this process with 5 ml of distilled water. Add the water to the biodiesel fraction and gently swirl. Collect and discard the bottom layer using a pipette. If necessary, this is a good place to stop. Pour your biodiesel in a centrifuge tube or an earthen wire flask with a stopper. Record any observations after allowing the biodiesel to sit. Next, add about 200 ml of water to a beaker and heat it to 80 degrees Celsius. Place the tube with your biodiesel in the hot water bath. Wait 10 to 15 minutes to allow any water remaining in your biodiesel to evaporate. You may also transfer your biodiesel to an earthen wire flask and heat it directly. Next you will analyze your biodiesel. Very low temperatures, biodiesel will gel. To test your biodiesel, you will need to make an ice salt water bath. Take about 100 ml of ice and stir in 1 to 2 tablespoons of salt. Take 1 to 2 ml of your biodiesel and place it into a test tube. Add 1 to 2 ml of regular diesel to a separate tube. Place the tubes into the ice salt water bath for 10 to 15 minutes. Record any observations as well as the temperature of the fuel after the time is up. Did your biodiesel gel? If not, why do you think it didn't? Next you will do a combustion test. Jane 2 cotton swabs and dip one into your biodiesel and the other into your starting seed oil. In the fume hood, light the 2 cotton swabs. Make observations on how long it took to start combustion, the color of the flame, and the presence of soot or particulates formed during combustion. Also record how many seconds it took for each swab to extinguish.