Exp 2. Extraction of Trimyristin from Nutmeg - Edited PDF

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Experiment 2

Flow Diagrams – fill in the blanks 1. Extraction of Trimyristin from Nutmeg

Add boiling stick

Nutmeg seed Record mass Discard brown residue and filter paper

Grind in mortar and pestle

Wash brown residue with 10 mL diethyl ether

Transfer to 100 mL conical flask

Collect 50 mL beaker

Add 50 mL diethyl ether to conical flask in fume hood

Add 2 mL acetone Cool to crystallise product Filter with Büchner funnel

Gravity filter solution

Stir 10 mins

Evaporate solvent Warm yellow oil

100 mL conical flask

Cover with 50 mL beaker

Water bath

Determine % w/w Trimyristin in seed

2. Saponification of Trimyristin to Myristic acid 0.300 g Trimyristin

2-3 boiling chips

10 mL ethanol

10 mL 6M NaOH

Filter with Büchner funnel Stand for 5 mins

100 mL round-bottom flask

Cool to room temp. Add 10 mL of ethanol.

Add 10 mL conc. HCl

Determine Myristic acid yield

Decant into 50 mL Yellow-orange 3. TLC & Melting P of Trimyrist water in 250 mL cid solution conical flask Reflux 30 minutes, demonstrator e solutions (you prepare two of these) must check! using separate spotters Spot onto TLC plate label spots develop in DCM/EtOH tank provided

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remove plate when solvent has almost reached the top Experiment 2

Mark solvent front, allow to dry

Pre Lab questions Develop spots in iodine tank, about 5 minutes 1. The structure of glucose (see theory section) is often depicted with one “squiggly” bond. What does this type of bond mean/represent? Determine Trimyristin & Myristic acid melting points The squiggly bond means that the OH can beand both op or down and that there are ultimately two sketch chromatogram, identify spots measure Rf values structures for glucose    2. What precaution must be taken to reduce diethyl ether fumes during this experiment? In order to reduce the ether fumes in the lab, you must place a small beaker upside down over any of your glassware which contains the diethyl ether (which should only be dispensed into a conical flask). It is also necessary to make sure that the lab environment is a well ventilated area.    3. What is the purpose of the condenser during the saponification reaction? Why must cooled water flow through the condenser during the reflux? - The purpose of the condenser during the saponification reaction is to prevent the solvent from boiling away. This is achieved because as the vapour from the boiling column rises into the reflux condenser column, it is then cooled by the surrounding water on the outside and condenses. - Thus cooled water must flow through the condenser during the reflux in order to maintain the reaction at boiling point of the solvent because it needs to be cool enough to condense the vapour. 4. Using the risk assessment provided on the second page of this experiment, determine the hazards and precautions associated with hydrochloric acid and sodium hydroxide? Hazards associated with hydrochloric acid: - Hydrochloric is harmful when swallowed - Hydrochloric is toxic via inhalation - Hydrochloric can also cause burns when in contact wit skin Precautions needed when handling hydrochloric acid: - Do not breathe in the fumes - Wear appropriate protective clothing Hazards associated with sodium hydroxide - Can cause severe burns when in contact with skin Precautions needed when handling sodium hydroxide - Wear appropriate clothing

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Experiment 2

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Experiment 2

Results 1. Extraction of Trimyristin from Nutmeg Nutmeg seed mass: 6.57 g Appearance of solution after diethyl ether evaporation: The appearance of a solution was similar to a yellow oily substance.  

Mass of Trimyristin product: 0.6 g 0.00083 mol

Number of moles Trimyristin:

Appearance of crystalline Trimyristin: The appearance of the crystalline trimyristin was a yellow powder   %w/w Trimyristin in Nutmeg seed: 9.13______________ % w/w Show yourcal cul at i ons: ( Massoft r i myr i st i n/nut megseedmass)x100 ( 0. 6/ 6. 57)x100=9. 132420091 =9. 1( 2s. f . )

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Experiment 2

2. Saponification of Trimyristin to Myristic acid Mass Trimyristin used in reaction: 0.3 g Number of moles Trimyristin used in reaction: 0.00041 mol Appearance of refluxing saponification reaction solution: It was a yellow- orange solution   Appearance of acidified saponification reaction solution: Dilute orangey substance.   Mass of Myristic acid product: 0.07 g

Number of moles Myristic acid product: 0.00031 mol Show yourcal cul at i ons: ( 0. 07/ 228. 3709)=0. 00030651891 =0. 00031( 2s. f )

Theoretical yield of Myristic acid: 0.28 g % Actual Yield of Myristic acid: _25________ % Show yourcal cul at i ons:Tr i myr i st i n:Myr i st i caci d->1: 3r at i o n( t r i myr i st i n)=0. 3/ 723. 16=0. 00041mol( 2s. f ) 0. 00041x3=0. 00123mol( t heor et i caln( myr i st i c) ) m( t heor et i calmyr i st i c)=nxM =0. 00123x228. 3709 m =0. 280896207 m =0. 28g( 2s. f . ) ->act ualyi el d% =m( act ual ) / m( t heor et i cal )x100 =( 0. 07/ 0. 28)x100=25% ( 2s. f)

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Experiment 2

Appearance of Myristic acid product: Almost clear liquid which was a bit cloudy  

3. TLC & Melting Point Analysis of Trimyristin and Myristic acid Photograph your chromatogram and record all Rf values. TLC Plate: Trimyristin

(solvent front: 5.9cm)

TLC Plate: Myristic Acid

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Experiment 2

rf (ours) = 0.6 cm, rf = 0.10

rf (ours) = 0.8 cm, rf = 0.14

rf (ours) = 1.2 cm, rf = 0.20

rf (ours) = 1.4 cm, rf = 0.24 rf (ours) = 4.1 cm, rf = 0.69 rf (ours) = 5 cm, rf = 0.85

rf (ours) = 3.8cm, rf = 0.64

rf (lab sample) = 5.6cm, rf = 0.95

rf (ours) = 5.6 cm, rf = 0.95 rf (lab sample) = 5.2 cm, rf = 0.88 rf (lab sample) = 5.6 cm, rf = 0.95

Rf Trimyristin: 0.95_______

R f Myristic acid: 0.85________

Melting point Trimyristin: ____52____ °C

Melting point Myristic acid: __58______ °C

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Experiment 2

Post–Lab Questions 1. The TLC eluent used in this experiment consists of a mixture of dichloromethane and ethanol. Ethanol is a very polar solvent to use in a TLC system. How would the polarity of the eluent change if the proportion of ethanol in the eluent was increased? What effect, if any, would this have on the TLC spot positions, given the fact that trimyristin is very non-polar? (see TLC lab theory) If the proportion of ethanol was increased, these polarity of the eluent would increase as the concentration of ethanol increases. Since the trimyristin is non polar, the distance that it would travel from the origin would decrease as it forms more bonds between the high ethanol concentration compared to the less concentrated ethanol – this means the retention factor value will decrease.

2. Provided below is an IR spectrum for trimyristin. Identify the IR peaks associated with C-H and C=O stretching, then circle and label these two bands on the provided IR spectrum.

C-H stretching

C-H stretching

C-H stretching

C=O stretching

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Experiment 2

3. Provided below is an IR spectrum for myristic acid. Identify the IR peaks associated with C-H, C=O and O-H stretching, then circle and label these three peaks on the provided IR spectrum.

O-H stretching

C-H stretching

4.

C=O stretching

The EI mass spectrum of myristic acid is provided below. Answer the following questions:

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Experiment 2

(a) Which peak on this spectrum corresponds to (M +) (ie. the molecular ion)? Provide its m/z value. It corresponds to the 228 peak.  (b) What does the peak at m/z = 229 correspond to? It corresponds to a carbon-13 isotope  (c) Calculate the difference between the molecular ion’s m/z value and the m/z value of the peaks at m/z = 199 and m/z = 185. Suggest reasonable molecular formulae (eg: C 2H5) for these calculated values. These two values correspond to radical fragments lost from myristic acid during the mass spectrometry experiment. Differences Molecular formulae 228-199 = 29 C2H5 228 – 185 = 43

C3H7

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