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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: jakel580 on April 24, 2019, 11:01:53 PM

Title: Determing chemical formula from IR spec and mass spec
Post by: jakel580 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!

Title: Re: Determing chemical formula from IR spec and mass spec
Post by: wildfyr on April 25, 2019, 07:46:33 AM

Wouldn't C9H18O make a lot more sense? Unsaturation of 1, which is the carbonyl

Title: Re: Determing chemical formula from IR spec and mass spec
Post by: rolnor on April 25, 2019, 09:44:31 AM

N-butanol is close but not exact

Title: Re: Determing chemical formula from IR spec and mass spec
Post by: Babcock_Hall on April 25, 2019, 09:56:32 AM

@OP,

Do you see indications of unsaturated carbons in the ¹H spectrum?

Title: Re: Determing chemical formula from IR spec and mass spec
Post by: wildfyr 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!