CHEM 801 (Module 5) Experiment 5.3: Aldol Reaction Analysis Report

This report details an aldol reaction experiment (CHEM 801, Module 5) conducted to demonstrate the influence of reaction conditions on the aldol reaction of cyclohexanone with 1-naphthalene carboxaldehyde. The experiment utilized solvent extraction, TLC plate analysis, and IR spectroscopy to analyze the reaction. The report includes the reaction scheme, detailed procedures, and results, including mass calculations and NMR analysis. The experiment aimed to determine the yield, identify the product, and assess the reaction's selectivity. The results and discussion section covers the preparation of LDA, the addition and condensation reactions, and the use of thin-layer chromatography. The report concludes with an overview of the aldol reaction, highlighting the purity of the products and the use of NMR for further separation. The experiment also discusses the advantages of solvent extraction techniques, including separation funnels and batch-mode extraction, along with the importance of drying the organic layer to remove water contamination.

CHEM 801 (MODULE 5)
EXPERIMENT 5.3 – ALDOL REACTION
STUDENT NAME
STUDENT REGISTRATION NUMBER
COURSE CODE

ABSTRACT
The goal of this lab experiment is to demonstrate how the reaction conditions influence the
outcome of an aldol reaction for the cyclohexanone with 1-naphthalene carboxaldehyde. The
addition of solvents in the reaction scheme demonstrated the kinetic and thermodynamic control
of the reaction using the highlighted substrates. The technique used in the solvent extraction is
the separation funnel, TLC plate analysis, and the IR spectroscopy.
REACTION SCHEME
In the first step the base removes a proton from the alpha carbon to form a resonance-stabilized
enolate. The nucleophilic enolate attacks the electrophilic carbonyl carbon of another molecule
of aldehyde. As a result, a new carbon to carbon bond is formed. It joins the alpha carbon of one
aldehyde to the carbonyl carbon of another aldehyde. The protonation of the alkoxide forms the
beta-hydroxy aldehyde (Vogel, et al. 1996). Carbon-carbon bond formation is one of the
cornerstones of organic synthesis. One of the key reactions used, the aldol condensation, features
the reaction of two carbonyl compounds to form a new β-hydroxy carbonyl compound. This
reaction can be performed under acid- or base-catalyzed conditions, and usually results in the
formation of an α, β-unsaturated carbonyl compound. The general base-catalyzed reaction is
shown in Scheme 1. One of the reacting species must contain a protonated α-carbon adjacent to
the carbonyl center. The proton attached to this carbon is acidic enough to be abstracted by base
to form an enolate species. Upon reaction with a second carbonyl compound, the β-hydroxy
carbonyl compound is formed, which can undergo E1cB elimination of water to form an E-
alkene.
(i) 0.09ml of cyclohexanone was added to the flask and left for about 30 minutes.
(ii) 0.12 naphthalene was added and left for about 2 minutes in the flask
(iii) 2 milliliters of NH4Cl was added and a separation funnel was set up as well as TIC
(iv) The concentration obtained from the above was used to perform NMR. The product
was purified by the use of column chromatography and the samples submitted for
NMR analysis. Determine the yield of the reaction, the identity of the product and the
selectivity of the reaction.
The first step obtains the enolate ion as,

The enolate in its stabilized resonance form is exposed to the nucleophilic addition such that
a new C-C bond is formed,
Such that J=8-10Hz to J=2-4 Hz
The rotation is of 1800
RESULTS AND DISCUSSION
The aldol reaction of cyclohexanone with 1-naphthalene carboxaldehyde (Siekierski n.d.)
A solution of Lithium diisopropylamide (LDA) is prepared by adding a solution of BuLi in
hexanes in equivalent to 1 titer dropwise using a syringe to a stirred solution of freshly distilled
diisopropylamine in THF at 00C under an inert atmosphere.
Component w.m Density Eq Mmol Amount (ml)
Lidisopropylamide 101.19 0.722 1.1 1 0.14
BuLi (0,58) 64.06 0.68 1 0.91 0.59
Cyclohexanone 98.14 0.947 1 0.91 0.09
C-heptalene carboxaldehyde 156.18 1.15 1 0.91 0.123
M1 = 66.9365g
M2 = 67.2722g
The total mass M=M2 – M1 , M= 0.3357g
When the same solution was passed through a burette and the results were placed in test tubes of
8 ml each,

M1 = 60.8443g
M2 = 60.8642g
The total mass is Mtotal = 60.8642g- 60.8443g
Mtotal = 0.019g
For LP,
M1 = 66.2205g
M2 = 66.3715g
The total mass is Mtotal = 66.3715g- 66.2205g
Mtotal = 0.151g
The addition and condensation reactions had a milky-white appearance in the reactor using the
thin layer chromatography.
Where CP represents the naphthalene and the AP represents the cyclohexanone

Figure 1 Aldol Condensation Reaction (Thermo Scientific - Molecular Spectroscopy 2013)
1.1 Dip
1 BuLi
1.1 a →1 m. mol
1 a →0.9 mmol
The experiment should be performed in triplicate to obtain an accurate titer.
The resulting bonding and disconnect is as shown below,
Rf = overall
product =0.3357 g
0.019 g
Rf =17.66842 …ratio

The illustrations of the NMR are attached to this report to demonstrate the behavior of the
chemicals as described in the experiment procedure. Drying is done to further separate the
aqueous layer from the organic layer and to remove the water contamination. The dust particles
from the surrounding may inevitably land in the mixtures to lower the purity of the crystals when
they are brought to test for their melting points. The advantage is that there are two layers formed
such that they tend to separate easily (Artxy 2016).
CONCLUSION
In a nutshell, the products obtained are generally considered quite pure. The melting ranges that
are obtained are near their literature values and the products are considered pure based on this
range. A small portion of the crystals was used to determine the melting point. The lab
experiment follows the three steps to perform the aldol reaction. The NMR is used to perform
further separation on the solvent extraction. There are several methods used in the separation for
both large scale and small-scale applications. The use of separation funnel is used in the small-
scale applications while the batch-mode extraction is used in the industrial laboratory solvent
extraction processes.
REFERENCES
Artxy. Lab on Aldol Condensation. May 2016. http://www.art-xy.com/2009/11/lab-report-on-
aldol-condensation.html.
Siekierski, S. "The Complex Formation- Association models of Solvent extraction of ions."
ournal of Radioanalytical chemistry, n.d.

Thermo Scientific - Molecular Spectroscopy. Aldol Condensation Reactions. May 20, 2013.
https://www.azom.com/article.aspx?ArticleID=8887.
Vogel, A I, A R Tatchell, B S Furnis, A Hannaford, and P.W.G Smith. Vogel's Textbook of
Practical Organic Chemistry. Prentice Hall, 1996.