Ester problem (1 Viewer)

[thebigticket]

Hi for esters with the same number of carbon atoms in the molecule which side (alkyl group or the anoate) part of the molecule determines the esters boiling point and why?

 

[nightweaver066]

Hi for esters with the same number of carbon atoms in the molecule which side (alkyl group or the anoate) part of the molecule determines the esters boiling point and why?

With carboxylic esters (the ones we look at in our syllabus), they're non-polar so the only IMF between the molecules are dispersion forces.

Increased molecular weight increases dispersion forces meaning greater boiling point so greater chain length (whether it be he alkyl or alkanoate part) leads to a greater boiling point.

 

[thebigticket]

However if you look at the boiling point of esters with same no of carbons such as ethyl butanoate and butyl ethanoate
butyl ethanoate has a slightly higher boiling point - why?

 

[nightweaver066]

However if you look at the boiling point of esters with same no of carbons such as ethyl butanoate and butyl ethanoate
butyl ethanoate has a slightly higher boiling point - why?

Come to think of it, carboxylic esters are actually slightly polar due to C = O bond.

Perhaps the different position of the C = O bond in butyl ethanoate allows for more effective dipole-dipole interactions hence a slightly higher boiling point. I'm not sure though. Ask your teacher or wait for someone else to reply :/

 

[golgo13]

For HSC chem it's about breaking bonds and molecular weight, basically the COO is gonna be uniform, so the breaking point for the rest of it is then determined by the carbon chain after wards. Now the question is which side is the longer carbon chain is to the double bond and that is where u'll find the answer