Lab report 6 - Grade: B PDF

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Emma Cannestra Experiment 6 Isolation of Trimyristin from Nutmeg and Preparation of Myristic Acid from Trimyristin by Hydrolysis Partners: Ana and Satya Introduction Natural product chemistry can be defined as, the isolation organic compounds from living organisms, mostly plants. Plants typically contain many compounds making these isolations very complex and tedious. In order to isolate these organic compounds, such as nutmeg, a process called “extraction” is performed. In this process, first the solid phase of the trimyristin is removed to a liquid phase (solvent). Once isolated, the compound is purified by recrystallization. During the recrystallization process, the impure (crude) trimyristin is dissolved in a warm solvent then left to cool. (1) During the cooling process the trimyristin crystallizes. In order to determine the purity after recrystallization, the melting point is taken. When taking melting points of organic molecules, a melting point range is typically reported. The melting point range is determined by heating an extremely small amount of the substance in a capillary tube until the first drop of liquid has melted, then the temperature is recorded. The tube remains in the machine until the sample has fully melted and once that point is reached, the temperature is recorded again to document an end to the melting point range. A substance with high purity will have a sharp melting point range (2 degrees or less between range). (2) Another extraction technique used is, hydrolysis, a strong base is added to a fat or oil and heated and the ester bonds of the triglycerides are hydrolyzed, and fatty acid salts are produced. (3) To determine the components of the product formed, the mixed melting point concept is used. A pure sample will have a high,

sharp melting point and an impure substance will have a low, broad melting point. A possible side reaction that could occur when preparing myristic acid is, the formation of too much NaOH. The H bond from the OH breaks causing an O-Na bond instead. Below is the mechanism of preparation of myristic acid.

Experimental Part 1 Place .4 g of Nutmeg in 50 mL flask

+ add 6 – 8 mL diethyl ether + stir for 15 – 20 minutes

Pasteur pipette + pack with cotton + add 2 mm of sand + add 1 cm of anhydrous sodium sulfate + place pipette in one holed septum and clamp vertically over 25 mL flask Remove solvent by vacuum pump

pet and allow to flow into 25 mL flask

+ rinse pipette with 0.5 mL of ether + dissolve residue with 1 mL of acetone using steam bath

+ allow to cool to room temp. + place in ice bath + collect solid solution using suction filtration with Hirsch funnel + rinse vial with cold acetone + transfer solid sample to pre-weighed vial and obtain weight

Experimental Part 2 Assemble micro-reflux apparatus + place 100 mg trymyristin, 1 mL ethanol, 1 mL of 10% NaOH, and boiling stone in vial + reflux mixture for 15 minutes + allow vial to cool to room temp. + pour mixture into 50 mL beaker containing 10 mL cold 10% HCl + shake + dilute solution with 5 mL cold water and collect solid by vacuum filtration + save a few milligrams + place remainder in test tube containing 3 mL pet. Ether + prepare filter pipet w cotton and 1 inch of Celite + filter myristic acid solution using pipet into test tube + use steam bath to dissolve solvent + determine percent yield and find boiling point to determine purity Table of Contents

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Trimyristin

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Melting point: 56-58°C

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Myristic Acid

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Melting point: 54-55°C

Results Chemical Name

Melting Point

Trimyristin Crude Myristic Acid Pure Myristic Acid 50:50 Mix

% yiled = Discussion

Mass

Percent Yield

56°C

.147

36%

49-50°C 54°C 49-52°C

.126 -

126% -

amount of pure product recovered ×100 amount of crudematerial used

The melting points found were close to the literature values of the melting points, this proves that the compounds extracted had a high purity value. However, the percent yields show the opposite. Due to such high values, it is apparent that there was more than the pure sample in the compound after being extracted. However, the low value for the crude mixture shows that there were also impurities and the experiment should be conducted again to obtain better results. Conclusion Both trimyristin and myristic acid were isolated then recrystallized throughout the experiment successfully. The isolation was completed through the use of extraction and acid base hydrolysis. The experimental data revealed that with the use of extraction and hydrolysis, different compounds can be isolated from things such as plants. These techniques can be used to find the composition of many plants and if they are harmful or not. Reference: (1) Weldegirma, Solomon. “Experimental Organic Chemistry: Laboratory manual for CHM (2) National Center for Biotechnology Information. PubChem Database. Trimyristin, CID=11148, https://pubchem.ncbi.nlm.nih.gov/compound/Trimyristin (accessed on Mar. 4, 2020) (3) National Center for Biotechnology Information. PubChem Database. Myristic acid, CID=11005, https://pubchem.ncbi.nlm.nih.gov/compound/Myristic-acid (accessed on Mar. 4, 2020)...