Why carboxyllic acid have higher boiling points that esters of the similar size?

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Why carboxyllic acid have higher boiling points that esters of the similar size?

2007-03-12 07:32:46 · 2 answers · asked by chaena m 1 in Science & Mathematics ➔ Chemistry

2 answers

The acid hydrogen and the lone pair on oxygen make for a perfect candidate for hydrogen bonding:

RCOO--H∆+ ----∆-O=C(OH)-R

The carboxylic acids form these "dimers" through H-bonding. This raises the intermolecular bonding forces considerably - which is not possible with esters.

The result is a much higher bp.

2007-03-12 07:47:53 · answer #1 · answered by Dr Dave P 7 · 1⤊ 0⤋

Because they can hydrogen bond, and esters can't - they only have dipole-dipole attractions.

2007-03-12 14:38:37 · answer #2 · answered by Gervald F 7 · 1⤊ 0⤋