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corrected to specify homologous
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Francesca Francesca
Francesca Francesca
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Why is the boiling point of homologous primary > secondary > tertiary alcohols whilst their solubility in water is the reverse?

From my understanding, for homologous alcohols, primary alcohols have the highest boiling points, because the OH group is the most accessible for other molecules to hydrogen bond to, therefore stronger intermolecular forces result in higher mp/bp.

One the other hand tertiary alcohols have the highest solubility in water because the packed structure of branches means the non-polar part of the molecule is condensed and therefore water near any part of the molecule can receive these hydrogen bonds. Doesn't this mean tertiary alcohols have the most accessible hydrogen bonds and therefore should have the highest melting point too?

Alternatively does this have to do with water being small and alcohols being larger therefore 'access' requirements to hydrogen bonding are different as larger alcohols need to be even closer than water to make a difference therefore the packing is less relevant as even being slightly away from the molecule means failure to access hydrogen bonds but water will be ok with being slightly away.

Why is the boiling point of primary > secondary > tertiary alcohols whilst solubility in water is the reverse?

From my understanding, primary alcohols have the highest boiling points, because the OH group is the most accessible for other molecules to hydrogen bond to, therefore stronger intermolecular forces result in higher mp/bp.

One the other hand tertiary alcohols have the highest solubility in water because the packed structure of branches means the non-polar part of the molecule is condensed and therefore water near any part of the molecule can receive these hydrogen bonds. Doesn't this mean tertiary alcohols have the most accessible hydrogen bonds and therefore should have the highest melting point too?

Alternatively does this have to do with water being small and alcohols being larger therefore 'access' requirements to hydrogen bonding are different as larger alcohols need to be even closer than water to make a difference therefore the packing is less relevant as even being slightly away from the molecule means failure to access hydrogen bonds but water will be ok with being slightly away.

Why is the boiling point of homologous primary > secondary > tertiary alcohols whilst their solubility in water is the reverse?

From my understanding, for homologous alcohols, primary alcohols have the highest boiling points, because the OH group is the most accessible for other molecules to hydrogen bond to, therefore stronger intermolecular forces result in higher mp/bp.

One the other hand tertiary alcohols have the highest solubility in water because the packed structure of branches means the non-polar part of the molecule is condensed and therefore water near any part of the molecule can receive these hydrogen bonds. Doesn't this mean tertiary alcohols have the most accessible hydrogen bonds and therefore should have the highest melting point too?

Alternatively does this have to do with water being small and alcohols being larger therefore 'access' requirements to hydrogen bonding are different as larger alcohols need to be even closer than water to make a difference therefore the packing is less relevant as even being slightly away from the molecule means failure to access hydrogen bonds but water will be ok with being slightly away.

Source Link
Francesca Francesca
Francesca Francesca
  • 19
  • 1
  • 3

Why is the boiling point of primary > secondary > tertiary alcohols whilst solubility in water is the reverse?

From my understanding, primary alcohols have the highest boiling points, because the OH group is the most accessible for other molecules to hydrogen bond to, therefore stronger intermolecular forces result in higher mp/bp.

One the other hand tertiary alcohols have the highest solubility in water because the packed structure of branches means the non-polar part of the molecule is condensed and therefore water near any part of the molecule can receive these hydrogen bonds. Doesn't this mean tertiary alcohols have the most accessible hydrogen bonds and therefore should have the highest melting point too?

Alternatively does this have to do with water being small and alcohols being larger therefore 'access' requirements to hydrogen bonding are different as larger alcohols need to be even closer than water to make a difference therefore the packing is less relevant as even being slightly away from the molecule means failure to access hydrogen bonds but water will be ok with being slightly away.