Extraction of Almond Essential Oil Through Steam Distillation
Comprehensive Examination
Formal Lab Report
Written by Ruqaia Mahmud (2345530)
For Elisabeth Cadieux
Organic Chemistry I
202-BZF-05 sect. 00006
Date of experiments: November 12 and December 5
Date of submission: December 23
Dawson College
Introduction
An essential oil is an oil that has been extracted from a plant’s fruit, leaves or roots, in huge
concentrations. This oil oftentimes gives the plant it’s signature “essence,” or fragrance, and the
properties of the oil vary from plant to plant. In this paper, the component in almond essential
oil, benzaldehyde, is extracted from the kernel of the almond.
Figure 1.1: Anatomy of an Almond 1 Figure 1.2: Structure of benzaldehyde2
Benzaldehyde is more commonly found within bitter almonds, since they have a larger
concentration in amygdalin. When almonds are processed or crushed, amygdalin breaks down
into benzaldehyde and hydrogen cyanide. Since the latter is toxic for human consumption in big
concentrations, bitter almonds must be consumed with caution and are not readily available in
goods stores. For this reason, this experiment is carried out using sweet almonds rather than
bitter ones.
1
Vasilenko, D., et al. "Identification of Novel Flavonoids and Their Antioxidant Properties in
Almonds." International Journal of Food Science & Technology, vol. 59, no. 6, 2024, pp. 1635-
1643. https://doi.org/10.1111/ijfs.13192.
2
"Essential Oils." Biopolymers Research Laboratory, Iowa State University, 2011,
https://www.engineering.iastate.edu/brl/files/2011/10/brl_essentialoils.pdf.
The structure of benzaldehyde is made of a benzene ring and containing a carbonyl group. This
gives this compound a very stable structure, since benzene ring are conjugated and therefore very
stable.
To determine the structure of our compound (and compare the purity of the sample), infrared
spectroscopy will be used. This method consists of studying how different structures and
functional groups absorb infrared radiation. By comparing the results obtained from infrared
spectroscopy of the obtained sample with literary values, the purity of the compound can be
determined.
Procedure
The procedure followed for this lab is one that is provided by our professor, with some
intentional modifications. For instance, the literature value for the percent yield that sweet
almonds would yield of benzaldehyde would be very low. Therefore, to increase chances of
getting a yield, the starting mass of the experiment used is 18.0956g instead of a mass around 5g.
In addition to that, the almonds are crushed by using a mortar to do so, since the almonds need to
be mildly processed for amygdalin to break down into benzaldehyde and hydrogen cyanide. All
the other steps in the procedure have been followed diligently.
Data
Table 1: Data Obtained from the Steam Distillation of Sweet California Almonds Through Steam
Distillation
Starting mass (g) 18.0965
Description of scent The compound obtained smelled of9 roasted
almonds.
Yield obtained (g) 0.4971
Physical description The compound is viscous and has a brown
color
Figure 2.1: IR Spectrum of Obtained Product:
Conclusion
After having steam distilled 18.0965g of crushed sweet Californian almonds (Prunus dulcis), a
yield of 0.4971g is obtained.
This experiment has been a success, since there was the obtention of a product that smells like
roasted almonds, which is the signature smell of benzaldehyde. However, the IR spectroscopy of
the products does not match the IR spectroscopy of benzaldehyde. In fact, benzaldehyde seems
to have many small peaks (Figure 2.2), whilst my graph does not display those same peaks. This
could be due to the fact that my compound is not pure, and the fact that this substance in
significantly low concentration compared to other substances that were steam distilled with it.
Indeed, according to the Beer-Lambert law, the intensity of a peak is directly proportional to the
concentration of a compound within the substance. Therefore, some of the smaller peaks might
not even be visible in the spectrum due to the low concentration of benzaldehyde in sweet
almonds.
Figure 2.2: IR Spectroscopy of Benzaldehyde3
3
Doc Brown. "Infrared Spectrum of Benzaldehyde." Doc Brown's Chemistry, 2001,
www.docbrown.info/page06/spectra/benzaldehyde-ir.htm.
For instance, my graph possesses a very steep decline around 3400cm-1 , which indicates the
presence of hydroxyl groups in the compound, since they absorb wavelength of this light more
readily. This means that there are hydrophobic substances containing hydroxyl groups that are
present within my compound, such as phenols. By comparing with the IR spectroscopy of ferulic
acid (Figure 2.3), which is a hydrophobic phenolic acid, it would make sense if this compound is
present in a larger concentration than benzaldehyde within the compound. It would also make
sense that a little bit of methanol’s composition influences the IR spectroscopy, since it is the
solvent for the product obtained, but the peak is not as prominent for the pure compound around
that wavelength (Figure 2.4).
Figure 2.3: IR Spectroscopy of Ferulic Acid 4
Figure 2.4: IR Spectroscopy of Methanol5
4
Agarwal, R. K., et al. "FT-IR Spectra of Ferulic Acid Isolate and Pure." ResearchGate, 2017,
https://www.researchgate.net/figure/FT-IR-spectra-of-ferulic-acid-isolate-and-
pure_fig2_305443069.
5
"IR Spectrum of Benzaldehyde." NIST Chemistry WebBook, National Institute of Standards and
Technology, https://webbook.nist.gov/cgi/cbook.cgi?ID=C67561&Type=IR-SPEC&Index=1.
The graph (Figure 2.1) also shows a significant peak around 1700cm-1 , which indicates the
presence of double bonds between O and C. This can be part of benzaldehyde but can also be
part of the composition of ferulic acid. Since methanol does not have a peak at that area, it would
make sense that this peak is not as prominent in the graph.
Overall, the compound may not have been pure, but isolating a compound from such small
concentration is difficult in itself. Additonally, the product obtained had the signature smell of
benzaldehyde, showing that a part of it has been effectively isolated. Thus, this experiment was a
success.
References
Agarwal, R. K., et al. "FT-IR Spectra of Ferulic Acid Isolate and Pure." ResearchGate,
2017, https://www.researchgate.net/figure/FT-IR-spectra-of-ferulic-acid-isolate-and-
pure_fig2_305443069.
Doc Brown. "Infrared Spectrum of Benzaldehyde." Doc Brown's Chemistry, 2001,
www.docbrown.info/page06/spectra/benzaldehyde-ir.htm.
"Essential Oils." Biopolymers Research Laboratory, Iowa State University, 2011,
https://www.engineering.iastate.edu/brl/files/2011/10/brl_essentialoils.pdf.
"IR Spectrum of Benzaldehyde." NIST Chemistry WebBook, National Institute of
Standards and Technology, https://webbook.nist.gov/cgi/cbook.cgi?ID=C67561&Type=IR-
SPEC&Index=1.
Vasilenko, D., et al. "Identification of Novel Flavonoids and Their Antioxidant Properties
in Almonds." International Journal of Food Science & Technology, vol. 59, no. 6, 2024, pp.
1635-1643. https://doi.org/10.1111/ijfs.13192.
