December 05, 2021, 09:43:20 AM
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Topic: I'm weak with IR and need to identify important peaks in this spectrum.  (Read 4185 times)

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Offline Babcock_Hall

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Hi I know it's been a while but I did more test and came to the conclusion (which was confirmed as correct by my TA) that the liquid product is mesityl oxide, and the solid is 3-nitrobenzoic acid. Just wanted to ass this as a follow up/conclusion to this.
@OP, To what do you assign the broad signal in the vicinity of 2950 wavenumber?
EDT
This sample looks too concentrated to me.
« Last Edit: July 05, 2021, 11:59:34 AM by Babcock_Hall »

Offline xshadow

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This is from a lab to separate an unknown binary mixture. This compound after performing a solubility test, I determined to be a carboxylic acid. I need help in identifying the peaks and determining what they are.

https://imgur.com/a/RXiROtN

Is hard to identify a compound only with IR


Don't see any carboxylic peak. The carboxylic peak are very large, usually over 3200. Not this case.

The 3054 signal is C-H sp2 stretching
The 2998 signal is C-H sp3 stretching

I ' m not sure if the  low signals at 2850 and 2685 can be attributed to an aldehydic group (usually they have two weak  signal at around 2800-2700) . 

It could be....because we know we have a C=O group (1700 signal)

Offline Babcock_Hall

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https://orgchemboulder.com/Spectroscopy/irtutor/nitrosir.shtml
PandHero,

Can you double-check the identities of the two compounds, and also which IR spectrum arises from the solid unknown versus the liquid unknown.  In your spectrum labeled "IR Cont" I see things that are consistent with a carboxylic acid.  In both "IR cont" and "Unknown IR 1" and I see some signals that might arise from a nitro group (see link), but from what you wrote above I thought that the carboxylic acid and nitro groups were part of the same compound.  Some of the signals in the spectrum shown in "IR Cont" are too intense to allow for easy interpretation.

« Last Edit: July 06, 2021, 09:57:18 AM by Babcock_Hall »

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