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Distillation of Star of Anise and Clove Oil Laboratory report for Organic Chemistry Lab...

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Steam Distillation of Star of Anise and Clove Essential Oil

Student Student Number CHEM 214 L04 February 7, 2021 Vanessa White Procedure Steam distillation, liquid-liquid extraction and rotary evaporation conducted to produce essential oils from samples of star anise and cloves. The star anise sample was ground and weighed in a round bottom flask (RBF) with a recorded initial mass of 5.02g. Approximately 80mL of water was measured using a graduated cylinder and subsequently added to the RBF with a magnetic

stir bar. The RBF was placed on a hot plate and secured onto a steam distillation apparatus as a distillation flask as displayed in figure 11 o The ground star anise and water solution was brought to a boil at 98 degrees C and tinfoil was secured around the RBF to maintain the warmth of rising steam. The condensed steam was collected in a receiving flask and the solution was poured in a separatory funnel. The receiving flask was rinsed with 5mL of diethyl ether and the contents were deposited into the separatory funnel. The separatory funnel was mixed and vented at regular intervals and the bottom inorganic layer was drained into an 50mL beaker. The upper organic layer was drained into an erlenmeyer flask. The inorganic solution was readded to the separatory with 5mL of diethyl ether and the separatory funnel was mixed and vented twice mor e 1 .

Figure 1. Diagram of Simple Distillation Apparatus

A new RBF was weighed with an initial mass of 40.958g. Magnesium Sulphate (MgS O 4) was added to the separated organic solution in the erlenmeyer flask to act as a drying agent. The organic solution was stirred until (MgS O 4 ) precipitate clumps were observed. The organic solution was gravity filtered followed by being deposited in a rotary evaporation apparatus. The final mass of the RBF was recorded as 41.208 g1 These steps were repeated with 5.08g of cloves, with an initial recorded clean RBF mass of 33.949g and a final recorded RBF mass of 34.424 g1 .

Results The mass of distilled star anise oil was calculated by subtracting the initial recorded mass of a clean RBF from the final recorded mass of the RBF containing the extracted essential oil.

Initial recorded mass 40.958g Final recorded mass: 41.207g

41.207 g−40.958 g=0.249 g With the mass of the distilled star anise oil, an overall percent recovery can be calculated for the extraction and purification process. Initial recorded mass Star anise: 5.02g Final recorded mass of distilled star anise: 0.249g

(0 .249 g ÷ 5.02 g)×100=4.96 % The mass of the Clove oil was calculated by subtracting the initial recorded mass of a clean RBF from the final recorded mass of the RBF containing the extracted essential oil. Initial recorded mass: 33.949g Final recorded mass: 34.423g

34.423 g−33 .949 g=0.474 g

Using this mass of the distilled oil of cloves, an overall percent recovery can be calculated for the extraction and purification process. Initial recorded mass of Cloves: 5.08g Final recorded mass of distilled oil of cloves: 0.4741g

(0.474 g ÷ 5.08 g)×100=9.33 % Table 1. Spectral Data of Samples Chemical Structure / Name

Wavenumber Experimental

(c m−1)

Intensity

Functional Group / Bonding Type Ether

Literature

1100

1175

Strong

3021.7

3023

Medium

SP

2

C-H

2963.3

2958

Medium

S P 3 C-H

3526.5

3518

Strong, Broad

Alcohol OH

1100

1160

Strong

Ether

3080.1

3077

Medium

S P 2 C-H

2846.5

2843

Medium

SP

2

Star of Anise Oil

Clove Oi l

3

C-H

3

Chemistry In the experiment that was conducted, the grounds of both star of anise and cloves were mixed with water in the distilling flask creating an immiscible mixture of water, grounds and essential oil. As the temperature in the distillation flask rose, the water began to evaporate bringing an uneven ratio of essential oil with it. As the steam and essential oil move through the cold water condenser, the steam condenses into a liquid and was deposited into an RBF in an ice water bath. 5ml of diethyl ether was added to the water and essential oil mixture in a separatory funnel. The addition of diethyl ether promoted the development of an upper organic layer which the essential oil dissolved into leaving the water as an immiscible inorganic layer. The inorganic layer was drained from the separatory funnel allowing for the separation of the organic mixture from the water. Magnesium sulphate was added to the organic mixture to perform the function of a drying agent as it complexes with water forming a hydrated magnesium sulphate precipitate which was later removed from the solution via gravity filtration. This is an important step as residual water left in the organic solution after liquid liquid extraction must be removed as to prevent impurity. Finally the essential oil was extracted from the organic solution via rotational evaporation. During the process or rotary evaporation, a vacuum is established which lowers the boiling point of both compounds. The organic mixture is heated resulting in the desired essential oil evaporating and condensing in a separate RBF where it is isolated from the diethyl ether. Interpretation After the conduction of this experiment it was determined that 0.249g and 0.474g of star anise and cloves were recovered respectively resulting in percent recoveries of 4.96% and 9.33%. The recovered masses of both samples are expected to be low as the initial mass of the

essential oils only accounted for a fraction of the mass of the grounds of both star of anise and cloves. From TLC analysis of pure eugenol and distilled oil of cloves with a 9:1 hexane to acetone mobile phase ratio, it was determined that the retention factor for the main spots were 0.31 and 0.27 for pure eugenol and distilled oil of cloves respectively. This suggests that the essential oil of distilled cloves was extracted effectively without significant impurity. Secondary spots related to the cloves essential oil spot were identified with higher retention factors which are likely due to the presence of less polar impurities. From TLC analysis of pure trans-anethole and distilled star anise oil with a 1:1 heptane to ethyl acetate mobile phase ratio, it was determined that the retention factor for the main spots were 0.73 and 0.71 for pure transanethole and distilled star anise oil respectively. This suggests that the essential oil of distilled star anise was extracted effectively without significant impurity. A secondary spot related to the star anise essential oil spot was identified with a lowerer retention factor which is likely due to the presence of a more polar impurity.

Conclusion The conduction of steam distillation, liquid-liquid extraction and rotational evaporation, essential oils of both cloves and star of anise were extracted and purified. The star of anise oil was observed to have had a percent recovery of 4.96% and the clove oil was observed to have had a percent recovery of 9.33%. Summary Box Sample

Initial Mass

Recovered Mass of Essential Oil

% Recovery

Star Anise

5.02g

0.249g

4.96%

Clove

5.08g

0.4741g

9.33%

References

1. Shipley, P; Robison, J. CHEM 214 Lab Manual (2021): Experiments in Organic Chemistry; University of British Columbia 2. Trans-Anethole; SDBS [online]; National Institute of Advanced Industrial Science and Technology (AIST). https://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi (accessed February 5, 2021). 3. Eugenol; SDBS [online]; National Institute of Advanced Industrial Science and Technology (AIST). https://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_disp.cgi?sdbsno=7116 (accessed February 5, 2021). Appendix Spectrum 1: Distilled Star Anise Oil, experimental infrared spectrum

Spectrum 2: Trans− Anet h ol e2 , literature infrared spectrum, liquid film

Spectrum 3: Distilled Clove Oil, experimental infrared spectrum,

Spectrum 4: Eugenol3 , literature infrared spectrum, liquid film...