Sample lab report for Experiment 194.1 in Palleros (pp. 398-a00)

Reaction of 9-Anthraldehyde with Maleic Anhydride via the Diels-Alder Reaction
Sam P. Le

January 18,2013

Purpose
The purpose of this experiment was to demonstrate the

utility of the Diels-Alder reaction by

reacting 9-anthraldehyde with maleic anhydride to form a9-anthraldehyde-maleic anhydride adduct. The 9-anthraldehyde-maleic anhydride adduct was characterized by melting point determination, infrared (IR) spectroscopy, UV-Vis absorption spectroscopy, as well as lH NMR spectroscopy. Reagent Table

[]

Compound

Molecular weight (s/mol)

9-anthraldehyde (9anthracenec arboxaldehyde)

206.24

r03-10s

Maleic anhydride

98.06

Toluene

92.14

Hexanes (mixture

of

Density
(g/mL)

Melting point ("C)

Boiling point ("C)

Miscellaneous information 52-s4

200

-93

110-lll

Corrosive, toxic Flammable

86.1 8

-95

68-70

Flammable

304.30

238-240

0.865

isomers)
9-

anthraldehyde -maleic

anhydride adduct

Nujol

N/A

DMSO-d6

84.17

1.19

18.4

r89

Heavy mineral oil
Deuterated

Acetone

58.08

0.79t

-94

56

Flammable

Structures, Chemical equations, and Mechanisms a CI4,O

+/,
1-

uil,nrl*"li-

\
U,r

o aleia- a^l^,X|riL

W\c,l"r*ls*r

Lt-twr-ta{)

C,r,ls- Aldzr)

b,

tdw',,'-

o

r1

6ru

4 ->^thnald"\1"-

zdl"t

^alo"

a"l1)";/'u

Sample lab report for Experiment

l9,{.l

in Palleros (pp. 39S-a00)

Procedure
The experiment was conducted according to the procedure describedin Palleros, Experimental
Organic Chemistry [2]. The only modification to the published procedure was the addition of a sand bath to improve heating during reflux.

Data and Observations
Amount of maleic anhydride used: 350 mg
Amount of 9-anthraldehyde used: 250 mg
Weight of 9-anthraldehyde-maleic anhydride adduct (crude): 325 mg
Appearance of adduct (crude): white, powdery solid

Amount of crude product used for recrystallization: 150 mg
Amount of recrystallized adduct recovered: 92 mg
Appearance of recrystallized adduct: colorless needles

MP of recrystallized adduct: 234-239'C

IR and UV-Vis spectra of 9-anthraldehyde are attached

as

Figure

I

and2, respectively.

IR, UV-Vis, and rH NMR spectra of recrystallizedg-anthraldehyde-maleic anhydride are attached as Figure 3 and 4 respectively.

Calculations
Calculation of theoretical yield attached as Figure 5.

Percent

yield :

:

(actual yield / theoretical yield)

x 100%o

(325 mg / 368 mg) x 100

:,88.3 %

Percent recovery of adduct in

recrystallization: (mass recovered / mass of crude used) x l00Yo

:

(92mgl

150 mg)

x

100

:61"h

Sample lab report for Experiment 19A.1 in Palleros (pp. 398-a00)

Discussion
In this experiment, the usefulness of the Diels-Alder reaction in organic synthesis was demonstrated by the reaction of 9-anthraldehyde with maleic anhydride to form a 9anthraldehyde-maleic anhydride adduct.

The Diels-Alder reaction is an example of a cycloaddition reaction and is an important reaction

in organic synthesis. The usefulness of the Diels-Alder reaction arises from the fact that two carbon-carbon bonds can be formed in a single step. Consequently, large and complex molecules can be achieved in an efficient manner. The Diels-Alder reaction is also referred to as a [4+2]

cycloaddition reaction because it involves the reaction of a conjugated diene, which contains 4 zr electrons, and a dienophile, which contains 2 n electrons. When a conjugated diene reacts with a

dienophile, a 6-membered ring product, known as an adduct, is formed [2].
In a Diels-Alder reaction, the bonds are broken and formed simultaneously and, therefore, is a concerted reaction. While the Diels-Alder reaction proceeds readily,

it is also

a reversible

reaction. At high temperatures, the Diels-Alder adduct decomposes into a conjugated diene and a dienophile [2]. Interestingly, the conjugated diene and dienophile formed in a retro-Diels-Alder

reaction are not necessarily the original starting diene and dienophile in some cases [3].