Abstract:
Acetone (1), CH3COCH3) and trans-cinnamaldehyde (2) undergoes a aldol reaction using
reagents ethyl alcohol (ethanol, CH3CH2OH) and 1.0M sodium hydroxide (NaOH) to form
dicinnamalacetone (3).
Introduction:
An aldol (aldehyde + alcohol) reaction occurs when aldehydes and ketones with a ?
hydrogen undergoes a base-catalyzed carbonyl condensation. “The equilibrium generally favors
condensation product in the case of aldehydes with no ? substituent (RCH2CHO) but favors
reactant for disubstituted aldehydes (R2CHCHO) and for most ketones” (McMurry, 2008). This
reaction is reversible and will lead to a ?-hydroxy aldehyde or ketone then to a ?, ?-unsaturated
product. When there is a mixed aldol condensation, the product can consist of four possible
products. A mixed reaction can only be successful if one of the aldehydes or ketones must be a
good donor (ex. ethyl aceto-acetate).
In this particular experiment, an aromatic aldehyde will react with an aliphatic ketone in
the presence of a base to form an aldol-type condensation product (Lehman, 2009).
Results and Discussion:
Stockroom acetone (1), 0.0734mL and Aldrich Chemical Co. trans-cinnamadehyde (2),
0.504mL underwent an aldol reaction to form dicinnamalacetone (3) using Stockroom 95%
ethanol and Stockroom 1.0M sodium hydroxide (NaOH).
Figure 1: Aldol Reaction of Acetone (1) and Trans-Cinnamaldehyde (2) to form
Dicinnamalacetone (3)
+ NaOH + H2O
------?
Acetone (1) Trans-Cinnamaldehyde (2) EtOH Dicinnamalacetone (3)
The predicted value of the product (3) was calculated to be 286.21 mg. The pure product
(3) has been reported to have a melting point of 144oC. The product (3) had a mass of 274.2 mg
which indicated a 95.80% yield, and a melting point range of 90 – 110oC. The high percent yield
indicates that not much product was lost during the transfer of the product (3) during vacuum
filtration. Washing with too much ethanol could account for the 5% loss because the product (3)
2
was soluble. The melting point indicated that although there was a high yield of product (3), it
was impure and may have contained starting material. The melting point differed by over 40oC.
Acetone Transcinnamaldehyde
Dicinnamalacetone
M.F. C3H6O C9H8O C21H18O
M.W. 58.1 132.2 286.21
Mmol 1.0 4.0 1.0
Mg 58.1 132.2 ----
Density 0.791 1.050 ----
M.P. -95oC -7.5oC 144oC
Experimental:
Acetone (1), 0.07mL was measured out using a 10-mL graduated cylinder and placed into
a 5-mL conical vial. Approximately 2.0mL of 95% ethanol was added to the acetone (1). Transcinnamaldehyde (2), 0.5mL was stirred into the reaction vial with 1.5mL of 1.0M of sodium
hydroxide. The reaction mixture was stirred for 10 minutes at room temperature. The precipitate
formed in less than a minute. The reaction vial was placed into a ice/water bath and allowed to
cool. The aldol condensation product (3) was collected by vacuum filtration with a Hirsch funnel
and 25-mL filter flask. Cold 4% Acetic acid/95% ethanol, 1mL was washed onto the product (3).
Approximately 1mL of cold 95% ethanol was used to wash out the reaction vial then poured onto
the product (3). The product (3) was transferred to a 9450.4mg vial and allowed to dry for a
week. The product weighed 274.2 mg and had a melting point range of 90 – 110oC
(Electrothermal Mel-Temp apparatus).

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