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Why do alkanes have higher boiling point than their ether counterparts?
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Mark
Why do alkanes have higher boiling point than their ether counterparts?
I second that the Van der Waals forces will dominate, because the dipole of the symmetrical ethers is perpendicular to the long axis of the molecule. In this case the number of electrons over a large surface area is going to play a bigger role in holding the molecules together.
Oxygen has the same number of electrons as -CH₂-, but because oxygen is more electronegative, it’s holding those electrons more tightly, making it less polarisable, and reducing the magnitude of the induced dipoles.
I suspect that ᵀ he effect is less apparent for dimethyl ether because the polar C-O bonds play a bigger role because the partial-positive charges on the carbons is not attentispread down the carbon chain, muting it, but remains a concentrated, bare, bright spot of charge, which can interact with the lone pairs on other ether oxygens. Additionally, there is less steric hindrance from the floppy alkyl groups. To prevent this kind of dipole-dipole attraction.
I second that the Van der Waals forces will dominate, because the dipole of the symmetrical ethers is perpendicular to the long axis of the molecule. In this case the number of electrons over a large surface area is going to play a bigger role in holding the molecules together.
Oxygen has the same number of electrons as -CH₂-, but because oxygen is more electronegative, it’s holding those electrons more tightly, making it less polarisable, and reducing the magnitude of the induced dipoles.
I suspect that ᵀ he effect is less apparent for dimethyl ether because the polar C-O bonds play a bigger role because the partial-positive charges on the carbons is not attentispread down the carbon chain, muting it, but remains a concentrated, bare, bright spot of charge, which can interact with the lone pairs on other ether oxygens. Additionally, there is less steric hindrance from the floppy alkyl groups. To prevent this kind of dipole-dipole attraction.
I suspect London forces dominate in the longer hydrocarbons, whereas they are disrupted by the ether bond. For shorter hydrocarbons, the dipole of the O-C bond is greater than the London forces, but this is reversed as the # of carbons increases.
I suspect London forces dominate in the longer hydrocarbons, whereas they are disrupted by the ether bond. For shorter hydrocarbons, the dipole of the O-C bond is greater than the London forces, but this is reversed as the # of carbons increases.
I dont recognize the distinction between observation and theory in your (?) question. The bp data youve tabulated is observational/empirical. The theory is that cooperativity of Van der Wals forced exceeded the energy of the dipole interaction for values on n, where n = # of carbons, with n beingMore
@AdamWorth I believe that your comment is a potential answer, can you please elaborate further, explaining why the Van der Waals forces exceeded the dipole interactions?More
I second that the Van der Waals forces will dominate, because the dipole of the symmetrical ethers is perpendicular to the long axis of the molecule. In this case the number of electrons over a large surface area is going to play a bigger role in holding the molecules together.
Oxygen has the same number of electrons as -CH₂-, but because oxygen is more electronegative, it’s holding those electrons more tightly, making it less polarisable, and reducing the magnitude of the induced dipoles.
I suspect that ᵀ he effect is less apparent for dimethyl ether because the polar C-O bonds play a bigger role because the partial-positive charges on the carbons is not attentispread down the carbon chain, muting it, but remains a concentrated, bare, bright spot of charge, which can interact with the lone pairs on other ether oxygens. Additionally, there is less steric hindrance from the floppy alkyl groups. To prevent this kind of dipole-dipole attraction.
I second that the Van der Waals forces will dominate, because the dipole of the symmetrical ethers is perpendicular to the long axis of the molecule. In this case the number of electrons over a large surface area is going to play a bigger role in holding the molecules together.
Oxygen has the same number of electrons as -CH₂-, but because oxygen is more electronegative, it’s holding those electrons more tightly, making it less polarisable, and reducing the magnitude of the induced dipoles.
I suspect that ᵀ he effect is less apparent for dimethyl ether because the polar C-O bonds play a bigger role because the partial-positive charges on the carbons is not attentispread down the carbon chain, muting it, but remains a concentrated, bare, bright spot of charge, which can interact with the lone pairs on other ether oxygens. Additionally, there is less steric hindrance from the floppy alkyl groups. To prevent this kind of dipole-dipole attraction.
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I suspect London forces dominate in the longer hydrocarbons, whereas they are disrupted by the ether bond. For shorter hydrocarbons, the dipole of the O-C bond is greater than the London forces, but this is reversed as the # of carbons increases.
I suspect London forces dominate in the longer hydrocarbons, whereas they are disrupted by the ether bond. For shorter hydrocarbons, the dipole of the O-C bond is greater than the London forces, but this is reversed as the # of carbons increases.
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