Lab 4 Results: Diels Alder Reaction
Lizz Radican
Lab 4
2/24/14
The Diels-Alder Reaction:
Results and Problems
1.)
Table 1: Mass, Percent Yield and Melting Points for Diels-Alder Reaction Products.
Product
Mass (g)
Percent Yield
Melting Points (°C)
Anhydride
8.87
88.2%
164.4-165.8
Dicarboxylic Acid
3.20
71.9%
176.6-180.1
Unknown
1.66
111%
168.7-176.0
2.) See attached calculations.
3.)
Table 2: Anhydride Product IR Data:
Functional Group or Bond
Peak Location(s) (cm-1)
Peak Intensity
Symmetric C=O Stretch
1840
Weak
Asymmetric C=O Stretch
1765
Strong
C-O Stretch
901
Very strong
Table 3: Dicarboxylic Acid Product IR Data:
Functional Group or Bond
Peak Location(s) (cm-1)
Peak Intensity
C=O Stretch
1702
Strong
O-H Stretch
3200-2500
Broad, medium
Sp2 C-H Stretch(s)
3021, 3082
Medium
Table 4: Lactone (Unknown) Product IR Data
Functional Group or Bond
Peak Location(s) (cm-1)
Peak Intensity
O-H Stretch
3100-2500
Broad, medium
C=O-O Stretch(s)
1175, 1158
Very strong
C=O Stretch(s)
1769, 1691
Strong
4. The reaction of the unknown with bromine gave a negative result meaning the solution did not turn clear, but rather, maintained an orangish brown color. This is interpreted to mean that bromine in not adding to either side of an alkene bond, so there is no C=C bond in the unknown compound.
The reaction of the dicarboxylic acid with bromine gave a positive result meaning that the solution turned clear as a result of bromine adding to both sided of the C=C bond. The dicarboxylic acid has a C=C bond.
Problems:
1. The carbonyl that is NOT incorporated into the ring structure has the greater IR stretching frequency. This is because the carbonyl incorporated into the ring structure shares some of its double bond character with the other double bond in the ring, giving it more single bond character. Thus, conjugated double bonds lower the stretching frequency of a carbonyl group by sharing the dipole character of the
Lab 4
2/24/14
The Diels-Alder Reaction:
Results and Problems
1.)
Table 1: Mass, Percent Yield and Melting Points for Diels-Alder Reaction Products.
Product
Mass (g)
Percent Yield
Melting Points (°C)
Anhydride
8.87
88.2%
164.4-165.8
Dicarboxylic Acid
3.20
71.9%
176.6-180.1
Unknown
1.66
111%
168.7-176.0
2.) See attached calculations.
3.)
Table 2: Anhydride Product IR Data:
Functional Group or Bond
Peak Location(s) (cm-1)
Peak Intensity
Symmetric C=O Stretch
1840
Weak
Asymmetric C=O Stretch
1765
Strong
C-O Stretch
901
Very strong
Table 3: Dicarboxylic Acid Product IR Data:
Functional Group or Bond
Peak Location(s) (cm-1)
Peak Intensity
C=O Stretch
1702
Strong
O-H Stretch
3200-2500
Broad, medium
Sp2 C-H Stretch(s)
3021, 3082
Medium
Table 4: Lactone (Unknown) Product IR Data
Functional Group or Bond
Peak Location(s) (cm-1)
Peak Intensity
O-H Stretch
3100-2500
Broad, medium
C=O-O Stretch(s)
1175, 1158
Very strong
C=O Stretch(s)
1769, 1691
Strong
4. The reaction of the unknown with bromine gave a negative result meaning the solution did not turn clear, but rather, maintained an orangish brown color. This is interpreted to mean that bromine in not adding to either side of an alkene bond, so there is no C=C bond in the unknown compound.
The reaction of the dicarboxylic acid with bromine gave a positive result meaning that the solution turned clear as a result of bromine adding to both sided of the C=C bond. The dicarboxylic acid has a C=C bond.
Problems:
1. The carbonyl that is NOT incorporated into the ring structure has the greater IR stretching frequency. This is because the carbonyl incorporated into the ring structure shares some of its double bond character with the other double bond in the ring, giving it more single bond character. Thus, conjugated double bonds lower the stretching frequency of a carbonyl group by sharing the dipole character of the