Experiment 3 PDF

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Experiment 3...

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Student name: Lauren Robertson Student ID: ler88957 TA name: Christopher DeAngelis Title: Extracting Trimyristin from Nutmeg Using Solid-Liquid Extraction Introduction The purpose of this experiment is to extract triglyceride trimyristin from ground nutmeg seeds. Extraction is the process of removing a component from a mixture. Specifically, this reaction extracts triglyceride trimyristin by taking advantage of each compound’s solubility, or lack thereof. Gravity filtration, simple distillation, reflux, suction filtration, and melting point determination are all techniques used in this experiment. Reflux is useful for heating a solution without losing any solvent. The trimyristin will dissolve in the solution of methylene chloride while the other nutmeg components will not. Then gravity filtration will separate the trimyristin and methylene chloride from the solid residue. Simple distillation will separate the methylene chloride from the trimyristin, and suction filtration will isolate the trimyristin from the remaining solute. The acetone used in the experiment removes remaining impurities from the trimyristin before using suction filtration, and methylene chloride acts as a solute for trimyristin while the other components of nutmeg are insoluble in it. Table of Reagents Compound

Structure

Molecu

Boilin

Meltin

lar

g

g Point y (℃)

Densit

(g/mL)

Weight

Point

(g/mol)

(℃)

Acetone

58.08

56

-

0.798

Methylene

84.93

39.8-

-

1.325

56-57

-

40

Chloride

Trimyristin

723.17

-

Safety Information As always, students must always wear gloves and goggles in the laboratory. Acetone and methylene chloride are flammable, so exposure of these chemicals to sparks and flames is crucial. Acetone and methylene chloride are toxic, and methylene chloride is also a carcinogen, so exposure and inhalation should be avoided at all costs. Avoid contact of these chemicals with the skin, eyes, and ingestion. Trimyristin has no specific hazards for this experiment. Snorkels must be intentionally placed to vacuum fumes from the laboratory. Caution should be exercised when working with hot glassware. All liquid waste should be disposed of in the appropriate bottle under the lab hood. Procedure Approximately 4.5 grams of ground nutmeg were measured and placed in a 100 mL roundbottom flask with several boiling chips. The flask was secured with a clamp to a ring stand

before 45 mL of methylene chloride was added. A condenser was attached to the flask and a heating mantle was added. After the solution began to boil, the mixture was refluxed for 30 minutes. After, the heating mantle was removed for the apparatus to cool. The solution was hot filtered into another round-bottom flask and the original flask was rinsed with methylene chloride before pouring it through the gravity filtration to wash any remaining trimyristin into the flask. Boiling chips were added, and a simple distillation apparatus was constructed. The solvent was distilled into Erlenmeyer flask in an ice-water bath. Distillation was stopped when 2-3 mL of methylene chloride was left in the boiling flask, and the distilled liquid was disposed of. After cooling to room temperature, the remaining methylene chloride and trimyristin mixture was cooled in an ice-water bath. Crystallization of the trimyristin began. Approximately 10 mL of acetone was added to the mixture and swirled to mix. Suction filtration was used to separate the trimyristin from the solute. The crystals were transferred to a 100 mL beaker and washed with another 10 mL of acetone. Suction filtration was conducted a second time for 5-6 minutes to remove all the liquid. The pure trimyristin was weighed and recorded before determining the melting point of the product with a Mel-Temp apparatus. Data and Observations 

Starting weight of nutmeg: 4.415 g



Volume of methylene chloride used to extract nutmeg sample: 42 mL



Temperature of the first drop of methylene chloride captured in the receiving flask: 36℃



Final weight of the extracted/isolated trimyristin product: 0.915 g



Melting point of the recovered trimyristin product (range): 53.1-55.4 ℃



Nutmeg was initially a fine brown powder.



As the methylene chloride nutmeg solution refluxed, the mixture bubbled and boiled.



The residue caught in the gravity filtration paper was brown and the filtered solution was golden-yellow.



The distillate was clear, leaving a deep golden-brown solution before adding to the ice bath for recrystallization.



The crystallized product appeared to be an orange yellow powder.



First suction filtration yielded a yellow-tinted white clumped powder.



Second suction filtration yielded pure white trimyristin crystals.

Results Theoretical yield of trimyristin: 4.415 𝑔 𝑜𝑓 𝑁𝑢𝑡𝑚𝑒𝑔 × 0.20 = 0.8830 𝑔 𝑡𝑟𝑖𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑛 4.415 𝑔 𝑜𝑓 𝑁𝑢𝑡𝑚𝑒𝑔 × 0.25 = 1.104 𝑔 𝑡𝑟𝑖𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑛 Percent yield trimyristin:

𝑝𝑒𝑟𝑐𝑒𝑛𝑡 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑦 =

𝑒𝑥𝑝𝑒𝑟𝑖𝑚𝑒𝑛𝑡𝑎𝑙 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑦 0.915 0.915 × 100% = 𝑡𝑜 × 100% 𝑡ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑦 1.104 0.8830

= 82.90 − 103.62% Discussion/Conclusion The percent recovery of trimyristin was exceptionally high at 82.90-103.62% compared to a normal 20-25% composition by weight. This result is probably very accurate considering that since the experiment was conducted over such a small sample size that even the smallest amount of impurity would cause a major increase in percent recovery. Impurities could easily be introduced in the transfer of product to multiple flasks in between suction filtrations if the flasks

were not cleaned properly or the impurities from the nutmeg passing through the filter when gravity filtration was performed. Proper folding of the filter paper and pouring the refluxed solution more slowly are potential solutions to prevent other components from passing through the filter paper. Using clean glassware is extremely important in the laboratory for both safety precautions and to prevent impurities from entering a solution- always use clean, dry glassware during experiments. It is also certainly possible that the methylene chloride was still present following the suction filtrations if the process was not carried out fully. It is worth noting that the experimental melting point of trimyristin was 53.1-55.4℃, which is significantly lower than the standard melting point of 56-57℃; this melting point depreciation provides evidence for impurity in the trimyristin because impurities in a substance decreases the substance’s melting point. The most obvious identity of the impurity would be acetone- if the pure trimyristin had not dried enough followed the suction filtration, acetone would act as an impurity in the product’s melting point determination. Dirty glassware, moisture in the air, or procedural error are all plausible causes of this unknown impurity given that the lab was conducted in a laboratory classroom that probably lacks certain scientific conditions that prevent these issues in a professional setting. Post-Lab Questions 1. Solid-liquid extraction is useful in this experiment to separate the trimyristin from the sample of ground nutmeg by taking advantage of the different solubilities of the components of the sample. Since trimyristin has a higher solubility than the other components of nutmeg, it is the only constituent that dissolves in the solution of nutmeg and methylene chloride during reflux. Reflux is used to heat the solvent (methylene chloride) to its boiling point and dissolve the trimyristin in it without any loss of its

vapor. The reflux apparatus consists of a round-bottomed reflux flask directly connected to a condenser (with its hoses appropriately connected). The vertically placed condenser is connected on its upper side with a thermometer adaptor and glass thermometer. This entire apparatus is completed by placing it in a heating mantle attached to a Variac controller and secured with ring clamps. The condenser cools the vapors of methylene chloride with its water flow and returns the solvent to the flask. Boiling chips are always added when heat is added to a solution to prevent flashing boiling. Reflux is followed by gravity filtration using a glass funnel, filter paper, and an Erlenmeyer flask to remove the other nutmeg components and then simple distillation separates the trimyristin from the methylene chloride solvent. Suction filtration completes solid-liquid extraction by isolating the trimyristin. 2. Simple distillation was used to separate the methylene chloride solvent from the extracted trimyristin. Methylene chloride has a boiling point of 40℃, but trimyristin is a nonvolatile compound; this means that the trimyristin will separate from the vaporing methylene chloride in distillation. The methylene chloride evaporated and condensed into the receiving flask, leaving a small amount of solvent with the trimyristin. This allowed for the complete isolation of the trimyristin through suction filtration. 3. It would not be either more helpful or effective to use fractional distillation during this experiment since trimyristin is completely nonvolatile. Fractional distillation is a much longer process than simple distillation and is most useful for separating compounds that have similar boiling points. In this case, the outcome would have been the same, but at a much slower rate since the methylene chloride would be continuously condensed and evaporated in the fractionating column, until the same conclusion was reached.

4. Acetone was used to rinse the trimyristin after the methylene chloride was removed because it is much more polar than trimyristin. The difference in polarities keeps the two from combining and the trimyristin from dissolving in the acetone. The acetone dissolves any polar impurities left in the trimyristin, including any remaining methylene chloride which is more polar, and therefore more soluble, in acetone. 5. Disposing of the leftover nutmeg in the hazardous waste container is necessary due to possibility of remaining methylene chloride in the mixture. There is no guarantee of the purity of the waste products after an experiment, especially in a lab working with hazardous and toxic materials. While it may not be as crucial to dispose of the nutmeg in a hazardous waste container as other chemicals, it is good practice, especially considering the flammability of the methylene chloride and acetone it was experimented with. There is no definitive way to predict what other substances will be added to a garbage can and how other waste products would react with the leftover nutmeg. Nutmeg on its own is not a dangerous substance, which is why it is a common ingredient in recipes, but in this experiment it should be disposed of in the hazardous waste container because of its possible impurities. 6. a) The experimental recovery is only 81.55-101.9% of the theoretical recovery of trimyristin, which is much higher than a 20-25% trimyristin composition of nutmeg. This is a strong indication of impurity in the sample. 𝐸𝑥𝑝𝑒𝑟𝑖𝑚𝑒𝑛𝑡𝑎𝑙 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑦 𝑡𝑟𝑖𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑛 (𝑚𝑜𝑙) = 5.02 𝑔 ×

   . 

= 0.00694 𝑚𝑜𝑙 = 6.94 × 10 𝑚𝑜𝑙 𝑡𝑟𝑖𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑛 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑒𝑑

𝑇ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑦 𝑡𝑟𝑖𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑛 (𝑚𝑜𝑙) = 24.62 𝑔 × 0.20 − 0.25 = 4.924 − 6.155 𝑔 𝑡𝑟𝑖𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑛

4.924 𝑔 𝑡𝑟𝑖𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑛 ×

1 𝑚𝑜𝑙 𝑡𝑟𝑖𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑛 = 0.00681 𝑚𝑜𝑙 𝑡𝑟𝑖𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑛 723.17 𝑔

6.155 𝑔 𝑡𝑟𝑖𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑛 ×

1 𝑚𝑜𝑙 𝑡𝑟𝑖𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑛 = 0.00851 𝑚𝑜𝑙 𝑡𝑟𝑖𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑛 723.17 𝑔

𝑀𝑜𝑙𝑎𝑟 𝑃𝑒𝑟𝑐𝑒𝑛𝑡 𝑅𝑒𝑐𝑜𝑣𝑒𝑟𝑦 =

=

𝑒𝑥𝑝𝑒𝑟𝑖𝑚𝑒𝑛𝑡𝑎𝑙 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑦 × 100% 𝑡ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑦

0.00694 × 100% = 101.9 − 81.55% 0.00681 − 0.00851

b)𝑇ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙 𝑦𝑖𝑒𝑙𝑑 𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑐 𝑎𝑐𝑖𝑑 = 0.00694 𝑚𝑜𝑙 𝑡𝑟𝑖𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑛 ×

      

=

0.0208 𝑚𝑜𝑙 𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑐 𝑎𝑐𝑖𝑑

c) 𝑃𝑒𝑟𝑐𝑒𝑛𝑡 𝑦𝑖𝑒𝑙𝑑 𝑚𝑦𝑟𝑖𝑠𝑡𝑖𝑐 𝑎𝑐𝑖𝑑 = 100% = 28.42%

   

× 100% =

. ×

    . 

. 

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