Introduction The purpose of this lab is to isolate the pure organic compound from nutmeg. Trimyristin is extracted from a nutmeg seed using Tert-butyl methyl ether. It is then recrystallized from acetone to pure Trimyristin. Hydrolysis and acidification make glycerol and myristic acid. The melting point of myristic acid is then found.
Procedure
The sand bath was set to 30%, then set it to 20%. 1.005 grams of ground nutmeg was weighed and transferred to the micro scale round-bottomed (RB) flask. 3.0mL of tert-butyl methyl ether was added and boiled. The black plastic connector was connected to the distillation column/air condenser. This was boiled for 10 minutes on the sand bath. The solids were allowed to settle for several minutes. The tip of the RB flask was tipped and the liquid was transferred to the centrifuge tube. The solid was settled again in the tube. Then, the liquid was transferred into the pressure filtration assembly. The Erlenmeyer flask was weighed to be 23.717 grams and tared. The filter liquid was placed into the tared flask, and pressure was applied to the hole in the filtration apparatus. 2mL of fresh Tert-butyl methyl ether to the RB flask. This was warmed briefly and let settle, then pipetted to the centrifuge tube again. The mixture was allowed to settle, and the liquid was filtered in the same pressure filtration apparatus. In the fume hood, a gentle stream of air was placed over the solution while warming the flask with one’s hand. The remainder should be left to air dry for 5 minutes and the weight was recorded to be 24.193 g. 1mL of acetone was added to the solid in the flask. The solution was warmed on the sand bath to dissolve, then cooled to room temperature over the course of 5 minutes. This was cooled in an ice water bath for another 15 minutes. The crystals were collected via vacuum filtration. A small amount of the sample was saved for the Melting Point, which was found to be 50-52 degrees Celsius. For the Hydrolysis portion of the lab, 60mg of the solid was weighed and transferred to a clean RB flask. 2mL of 6M Sodium Hydroxide, 2mL of 95% ethanol and a boiling chip were added. The solution was refluxed on the sand bath for 45 minutes. The Trimyristin was recrystallized a second time, cooled yet again to room temperature and then placed in an ice bath. The solid was dissolved with 3 drops of acetone, then vacuum filtrated and left to dry. The melting point of the second recrystallization was taken and found to be 53-55 degrees Celsius. The final compound was weighed to be ________. All of the liquids were discarded in the “Organic Liquid Waste” container. The Mel-Temp was turned off, as well as the air and vacuum.
Results
% recovery of crude Trimyristin from nutmeg 0.476 g / 1.005 g * 100 = 47.4 %
% recovery of recrystallized Trimyristin from nutmeg 0.119 g / 1.005 g * 100 = 11.84 %
Theoretical of Myristic Acid: 0.06 g Trimyristin * 1 mol T / 723.16 g T = .083 mmol T
.083 mmol T * 3 mmol Myristic Acid/ 1 mmol T = 0.25 mmol Myristic Acid
.25 mmol M * 228.37 g / mol M * 1 mol / 1000 mmol = 0.057 g Myristic Acid
Actual of Myristic Acid:
0.047 g actual / 0.057 g theoretical myristic acid * 100 = 82.5 %
Discussion The percent recovery of the crude Trimyristin was 47.4%. This was expected to be much higher than the average 20-25% recovery from nutmeg, as it still contained many impurities. After the first recrystallization, the percentage dropped significantly to only 11.84%. This is slightly lower than expected. This could have been from not waiting long enough for crystals to form, or a small amount of Trimyristin stayed dissolved in the solution. That being said, the percent yield of myristic acid from the recrystallized Trimyristin was
