Using the data given below, determine the structure of the compound that best fi
ID: 1022193 • Letter: U
Question
Using the data given below, determine the structure of the compound that best fits all the spectral data. Remember to record the answers to all questions.
A research student accidentally discarded her carboxylic acid product in the flammable waste container. She was able to extract her compound from the flammable waste container using a chemically active extraction procedure she learned about in organic chemistry laboratory.
31. How what this student able to recover her acidic product from the waste container?
a. Preformed a liquid-liquid extraction with an acid.
b. Preformed a liquid-liquid extraction with a base.
c. Preformed a liquid-liquid extraction with water.
d. Evaporated off all the flammable liquid and recrystallized the resulting solid.
Once the student was able to recover what she hopes is her acidic compound, she analyzed the compound with GC/MS, UV-VIS, IR, 1H NMH and 13C NMR. She now needs help analyzing her spectral data to determine if the compound she recovered was in fact her acidic compound.
Additional Information:
Molecular Formula: C7H6O2
Mass Spectrum Data: UV-VIS Data:
Molecular Ion (M+) 122 m/z lmax 241 nm
Fragment 105 m/z (base peak) (log10 e 4.1)
Fragment 77 m/z
Answer the following questions.
32. What is the HDI for this acidic compound?
a. 0
b. 1
c. 4
d. 5
33. This compound has an lmax at 241 nm. This implies that the compound contains____________.
a. isolated double bonds
b. one double bond
c. conjugated system
d. no multiple bonds at all
34. The base peak in the mass spectrum for this compound indicated the compound lost a fragment that has an m/z = 17. This fragmentation corresponds to the loss of a(n) __________ group.
a. hydroxyl
b. carbonyl
c. methyl
d. ethyl
35. The large fragmentation at m/z 77 is due to the ______________.
a. benzyl cation
b. acylium cation (R-CºO+)
c. phenyl cation
d. cyclohexyl cation
36. What absorptions in the IR spectrum will help this student determine that she has successfully extraction her acidic compound from the waste container?
a. The peak at 1696 cm-1
b. The broad peak in the range between 2500 – 3400 cm-1.
c. The peaks at 1251 and 1288 cm-1.
d. All of the above
37. The normal range for the carbonyl group of a carboxylic acid in the IR spectrum is 1725 – 1700 cm-1. Why is the carbonyl group of this compound appear at 1696 cm-1?
a. The carbonyl group is in conjugation with the aromatic ring.
b. The oxygen of the carbonyl must be protonated.
c. The carbonyl must be hydrogen bonding with water.
d. That is not the carbonyl peak at 1696 cm-1.
38. What part of this compound gives rise to the peak the furthest downfield (12.79 ppm) in the 1H NMR spectrum?
a. Aromatic protons
b. Proton attached to the oxygen of the hydroxyl group
c. Carbonyl group
d. No protons absorb this far downfield, therefore it must be an impurity
39. The identify of the student’s acidic compound is ____________.
a. acetic acid
b. phenyl acetic acid
c. benzoic acid
d. diphenyl acetic acid
40. Does 13C NMR support your conclusion?
a. Yes, the peak at ~ 170 ppm is the carbon of the carbonyl and the peaks in the range of 128 – 134 ppm are the aromatic carbons.
b. No, there is not enough data on the 13C NMR to support my conclusion.
Explanation / Answer
31. How what this student able to recover her acidic product from the waste container?
b. Preformed a liquid-liquid extraction with a base.
32. HDI of the compound is,
d. 5
33. This compound has an lmax at 241 nm. This implies that the compound contains____________.
c. conjugated system
34. The base peak in the mass spectrum for this compound indicated the compound lost a fragment that has an m/z = 17. This fragmentation corresponds to the loss of a(n) __________ group.
a. hydroxyl
35. The large fragmentation at m/z 77 is due to the ______________.
c. phenyl cation
36. The absorptions in the IR spectrum that will help this student determine that she has successfully extraction her acidic compound from the waste container is,
b. The broad peak in the range between 2500 – 3400 cm-1.
37. The normal range for the carbonyl group of a carboxylic acid in the IR spectrum is 1725 – 1700 cm-1. The carbonyl group of this compound appear at 1696 cm-1 due to,
a. The carbonyl group is in conjugation with the aromatic ring.
38. The part of this compound giving rise to the peak the furthest downfield (12.79 ppm) in the 1H NMR spectrum is,
b. Proton attached to the oxygen of the hydroxyl group
39. The identify of the student’s acidic compound is ____________.
c. benzoic acid
40. The 13C NMR support your conclusion,
a. Yes, the peak at ~ 170 ppm is the carbon of the carbonyl and the peaks in the range of 128 – 134 ppm are the aromatic carbons.
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