Question

1. Which one of the following two compounds would you expect to have a higher solubility in liquid CO2. Explain your reasoning in a few sentences:

2. Explain why percent recovery is utilized in the CO2 extraction of Eugenol as opposed to a theoretical yield. Limit yourself to 1-3 sentences.

3. List 3 signals that should be observed in the IR spectrum of Eugenol (whose structure is shown to the right).

4. In your own words, explain the purpose of sealing the 15 mL centrifuge tube and submerging it into hot water bath.



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Answer 1

1. The compound with higher solubility in liquid CO2 would be the one that can form stronger intermolecular interactions with CO2 molecules. For example, compounds that can form hydrogen bonds or have larger surface areas tend to have higher solubility in CO2.

2. Percent recovery is used in CO2 extraction of Eugenol because it allows us to determine how much of the Eugenol was successfully extracted from the plant material. The extraction process is not 100% efficient, so using theoretical yield would not accurately reflect the amount of Eugenol obtained.

3. In the IR spectrum of Eugenol, you would expect to observe three signals: a broad and strong peak around 3300-3600 cm-1 (O-H stretch of alcohol group), a sharp and strong peak around 1700-1750 cm-1 (C=O stretch of aldehyde group), and weak peaks around 1500-1600 cm-1 (aromatic ring stretch).

4. Sealing the centrifuge tube prevents volatile compounds from evaporating during the extraction process, while submerging it in a hot water bath increases temperature to enhance extraction efficiency by promoting the dissolution of the desired compound into liquid CO2.