Biodiesel and Dyes Synthesis Lab Introduction Biodiesel The purpose of this lab was to produce biodiesel from vegetable oil through the transesterification of methodoxide The order of steps that will occur in this lab are preparation of methoxide synthesis of the biodiesel separation of the biodiesel testing the biodiesel with gas chromatography and determination of the fatty free acid content of the oil used by titration Animal fats and vegetable oils are made up of triglycerides which can by make into biodiesel through transesterification Methanol and Ethanol are most commonly used in this process because of the hindrances in larger alcohols In transesterification an alcohol reacts with an ester which produces another ester This ester in turn reacts with methanol in the formation of fatty acid methyl esters and glycerol One thing that requires attention in this process is fatty free acids Fatty free acids are produced as oil is broken down In order for these to be converted in transesterification they first have to be converted into esters Note that fatty free acids can be neutralized with excess base this produces glycerol Another thing that s important to this lab is that the stating materials be free of water If they are not saponification rather than transesterification In selecting the base to use for this experiment the rate of dissolution of methanol by the base was taken into consideration KOH dissolved much quicker than NaOH in methanol and so it was used Also another thing had to be considered when considering the base That was the purity of the base used The purer the base the less needed to be used and vice versa Dyes In this lab several dyes are prepared Those dyes are phenolphthalein fluorescein and methyl red Both phenolphthalein and methyl red are used as pH indicators Methyl red turns red in acidic solutions while phenolphthalein turns pink in basic solutions Flurescein on the other had is used as a fluorescent tracer in many applications It is a dark orange red powder that is soluble in both water and alcohol It is used as a tracer because it glows under UV illumination Procedure Biodiesel Part Preparing the methoxide solution 1 Measured out 250 mL of fresh unused vegetable oil into a 500 mL flask added a stir bar and a thermometer 2 Placed the flask on the hotplate 3 Heated the oil while stirring up to 55oC Note temperature maintained as close to 55 oC as possible while not exceeding 60 oC Also note Methanol boils at 65 oC 4 While the oil was heating measured out 50 mL of Methanol into a 125 mL flask 5 Added 1 41 grams of KOH to the methanol 6 Covered the flask with Parafilm to prevent absorption of water 7 Swirled the contents of the flask until all of the KOH dissolved Transesterification 8 When the oil temperature reached 55 oC added the methoxide solution to the oil ensuring that the stirring speed is sufficient to mix the solution completely 9 Brought the temperature back up to 55 oC and maintained that temperature for 1 hour Determining FFA content 10 Measured 40 mL of 2 propanol into a clean 125 mL flask 11 Added 4 mL of used waste oil to the flask and swirled to mix 12 Warmed the mixture with the hotplate and swirled periodically until the solution is clear and not cloudy 13 Added 3 drops of phenolphthalein indicator to the solution and swirled to mix 14 Obtained 20 mL of 0 1 KOH solution in the 100 mL beaker 15 Fillws the 10 mL Mohr pipette and using your thumb lowered the level to the 0 mark 16 While swirling the oil and propanol mixture added the KOH dropwise from the pipette until the solution turned pink and persisted for at least 15 seconds 17 Noted the final volume in the pipette 18 Dived your result by 4 For every mL of KOH solution needed to titrate the oil you needed to add 1 additional gram of KOH to the methoxide solution for every liter of oil to be reacted Finishing 19 After the reaction had progressed for an hour removed the flask from the heat and poured the contents into a clean poly bottle 20 After 30 min noticed separation of the Biodiesel on top and the glycerin layer on bottom Allow the Biodiesel to fully separate for at least a day 21 Poured off the Biodiesel layer into a separate container being careful not to allow any of the glycerin layer to get in 22 Added half as much deionized water as Biodiesel to your container and agitate not vigorously 23 Allowed the Biodiesel to separate and drained off the water 24 Repeated this process until the wash water is no longer cloudy 25 Allowed the washed Biodiesel to dry until it is clear Note this could take a week Testing Wash Test 26 Put 150mL of the Biodiesel into a clear poly bottle 27 Added 150 mL of deionized water to the bottle and capped the bottle tightly 28 Shook vigorously for approximately 10 15 seconds and then allow to settle 29 The oil and water should separated within 30 min with the Biodiesel on top and the water on the bottom Note if it does not separate cleanly it can indicate either excess soap formation from too much base or incomplete reaction Methanol Test 30 Dissolved 25 mL of your product into 225 mL of methanol Note the Biodiesel should dissolve completely there is any residue on the bottom then your reaction was incomplete and either more methanol needs to be added or the reaction time and temperature need to be adjusted Dyes Synthesis Part Phenolphthalein 1 Combined 0 03g phenol with 0 03g phthalic anhydride in a 125mL Erlenmeyer flask 2 Mixed with 10 drops concentrated H2SO4 3 Heated in the hood with a Bunsen burner 4 Heated until SO3 fumes stop forming Note was left with small amount of orange solution Also note this is highly acidic 5 Added 15 20mL of 0 1M NaOH solution should turn colorless 6 Added 1mL of 5M NaOH solution should turn magenta Note more concentrated NaOH if color change does not occur 7 Saved solution in a small beaker covered in Parafilm for next week Fluorescein 8 Combined 0 02g resorcinol meta dihydroxybenzene and 0 02g phthalic anhydride in a 125mL Erlenmeyer flask 9 Mixed with 10 drops of concentrated H2SO4 Note solution is green 10 Heated in the hood with a Bunsen burner An orange solid formed in a bright green solution 11 Heated until SO3 fumes stop forming 12 Allowed solution to cool 13 Gravity filtered the solid from the solution 14 Added 20mL of 0 1M NaOH to the filtrate and observed the color of the solution 15 Added a small amount of the solid isolated to a beaker and dissolved it in 20mL of 0 1M NaOH Observed the color of the