Solution Found!
N-Methylpyrrolidine has a boiling point of 81 °C, and
Chapter 23, Problem 39SP(choose chapter or problem)
N-Methylpyrrolidine has a boiling point of \(81^{\circ} \mathrm{C}\), and piperidine has a boiling point of \(106^{\circ} \mathrm{C}\).
(a) Explain this large difference (\(25^{\circ} \mathrm{C}\)) in boiling point for these two isomers.
(b) Tetrahydropyran has a boiling point of \(88^{\circ} \mathrm{C}\), and cyclopentanol has a boiling point of \(141^{\circ} \mathrm{C}\). These two isomers have a boiling point difference of \(53^{\circ} \mathrm{C}\). Explain why the two oxygen-containing isomers have a much larger boiling point difference than the two amine isomers.
(c) N,N-Dimethylformamide has a boiling point of \(150^{\circ} \mathrm{C}\), and N-methylacetamide has a boiling point of \(206^{\circ} \mathrm{C}\), for a difference of \(56^{\circ} \mathrm{C}\). Explain why these two nitrogen-containing isomers have a much larger boiling point difference than the two amine isomers. Also explain why these two amides have higher boiling points than any of the other four compounds shown (two amines, an ether, and an alcohol).
Equation Transcription:
Text Transcription:
81^{o}C
106^{o}C
25^{o}C
88^{o}C
141^{o}C
53^{o}C
150^{o}C
206^{o}C
56^{o}C
N-CH_3
81^{o}C
88^{o}C
H-C-N
CH_3
CH_3
150^{o}C
N-H
106^{o}C
OH
141^{o}C
CH_{3}-C-N
CH_3
206^{o}C
Questions & Answers
QUESTION:
N-Methylpyrrolidine has a boiling point of \(81^{\circ} \mathrm{C}\), and piperidine has a boiling point of \(106^{\circ} \mathrm{C}\).
(a) Explain this large difference (\(25^{\circ} \mathrm{C}\)) in boiling point for these two isomers.
(b) Tetrahydropyran has a boiling point of \(88^{\circ} \mathrm{C}\), and cyclopentanol has a boiling point of \(141^{\circ} \mathrm{C}\). These two isomers have a boiling point difference of \(53^{\circ} \mathrm{C}\). Explain why the two oxygen-containing isomers have a much larger boiling point difference than the two amine isomers.
(c) N,N-Dimethylformamide has a boiling point of \(150^{\circ} \mathrm{C}\), and N-methylacetamide has a boiling point of \(206^{\circ} \mathrm{C}\), for a difference of \(56^{\circ} \mathrm{C}\). Explain why these two nitrogen-containing isomers have a much larger boiling point difference than the two amine isomers. Also explain why these two amides have higher boiling points than any of the other four compounds shown (two amines, an ether, and an alcohol).
Equation Transcription:
Text Transcription:
81^{o}C
106^{o}C
25^{o}C
88^{o}C
141^{o}C
53^{o}C
150^{o}C
206^{o}C
56^{o}C
N-CH_3
81^{o}C
88^{o}C
H-C-N
CH_3
CH_3
150^{o}C
N-H
106^{o}C
OH
141^{o}C
CH_{3}-C-N
CH_3
206^{o}C
ANSWER:
Solution:
Step 1
N-Methylpyrrolidine has a boiling point of 81 °C whereas piperidine has a boiling point of 106 °C due to higher polarity. In piperidine N-H bond, it forms H-bonding. As N is more electronegative thus the molecule is polar due to presence of N-H bond.But in case of N-Methylpyrrolidine there is no polar bond. This results a difference of boiling point (25oC)of the two isomers.
