November 26, 2024, 12:18:42 PM
Forum Rules: Read This Before Posting


Topic: Determing chemical formula from IR spec and mass spec  (Read 1423 times)

0 Members and 1 Guest are viewing this topic.

Offline jakel580

  • Very New Member
  • *
  • Posts: 1
  • Mole Snacks: +0/-0
Determing chemical formula from IR spec and mass spec
« on: April 24, 2019, 11:01:53 PM »
The IR spec clearly shows a carbonyl is present, which means an oxygen is present.

The mass spec data shows there is an M+ peak of 142, with no Cl/Br present.

From this data, I'm gathering a formula of C10 H6 O.  (10 X 12 + 6 + 16 =142)  This leads to a degree of unsaturation of 8, which seems fairly high.  I feel as if I'm missing something here and any help would be greatly appreciated, thanks!

Edit:  Forgot about integral scaling in the hnmr, which will change the number of protons.  Thanks anyway!
« Last Edit: April 25, 2019, 12:12:55 AM by jakel580 »

Offline wildfyr

  • Global Moderator
  • Sr. Member
  • ***
  • Posts: 1776
  • Mole Snacks: +203/-10
Re: Determing chemical formula from IR spec and mass spec
« Reply #1 on: April 25, 2019, 07:46:33 AM »
Wouldn't C9H18O make a lot more sense? Unsaturation of 1, which is the carbonyl

Offline rolnor

  • Chemist
  • Sr. Member
  • *
  • Posts: 2299
  • Mole Snacks: +154/-10
Re: Determing chemical formula from IR spec and mass spec
« Reply #2 on: April 25, 2019, 09:44:31 AM »
N-butanol is close but not exact

Offline Babcock_Hall

  • Chemist
  • Sr. Member
  • *
  • Posts: 5707
  • Mole Snacks: +330/-24
Re: Determing chemical formula from IR spec and mass spec
« Reply #3 on: April 25, 2019, 09:56:32 AM »
@OP,

Do you see indications of unsaturated carbons in the 1H spectrum?
« Last Edit: April 26, 2019, 08:22:03 AM by wildfyr »

Offline wildfyr

  • Global Moderator
  • Sr. Member
  • ***
  • Posts: 1776
  • Mole Snacks: +203/-10
Re: Determing chemical formula from IR spec and mass spec
« Reply #4 on: April 26, 2019, 08:20:55 AM »
More like, do you see any unsaturated carbons in the FTIR! I don't. OP where would these show up normally?

This is a pretty simple molecule OP, you can do it!

Sponsored Links