April 11, 2021, 11:33:40 PM
Forum Rules: Read This Before Posting


Topic: IR spectra of trans-cinnamic acid vs methyl trans-cinnamate  (Read 380 times)

0 Members and 1 Guest are viewing this topic.

Offline IA97

  • Very New Member
  • *
  • Posts: 1
  • Mole Snacks: +0/-0
IR spectra of trans-cinnamic acid vs methyl trans-cinnamate
« on: September 27, 2020, 07:47:31 PM »
I am comparing the IR spectra of methyl trans-cinnamate and trans-cinnamic acid. For the IR spectrum of methyl trans-cinnamate, aromatic overtones can be seen (2112 cm-1, 1995 cm-1, and 1923 cm-1), while they are not present in the IR spectrum of trans-cinnamic acid. Both of these molecules contain the same aromatic ring, so how come only one of them contains the aromatic overtones? I have attached the relevant spectra. Any help would be much appreciated, thank you!

Offline Babcock_Hall

  • Chemist
  • Sr. Member
  • *
  • Posts: 4600
  • Mole Snacks: +279/-19
Re: IR spectra of trans-cinnamic acid vs methyl trans-cinnamate
« Reply #1 on: September 28, 2020, 08:15:57 AM »
I am not sure of the answer, but I do see weak, unlabeled peaks in the cinnamic acid spectrum in this vicinity.

Sponsored Links