[Violagirl]

For my lab, we have to analyze two spectrums for the compounds listed in the subject line. I took notes on potential functional groups for each of the peaks and wanted to see if I could get feedback on if I'm on the right track with it or not. My spectrums are on the bottom.





For the first spectrum, we prepared a solid sample of 4-methoxyacetopheone and a methylene chloride solvent was added too. I got the following for possible peaks:

Between 3006-2853: C-H stretch

1601: Aromatic, C=C stretch

1739:
Ketone: C=O
Ester: C=O?

1460-1340: Alkane, C-H bond

1258, 835, 1418, 2926-methylene chloride


For the second spectrum of biodiesel:

3008:
Alkene, =C-H stretch

3008-2854:
Carboxylic Acid, O-H stretch

1743:
Ketone, C=O stretch

1461-1437
Alkanes, C-H bond

It also asks for where the prescence or appearence of an alcohol would appear from using methanol to prepare the sodium methoxide and glycerol reaction. Since OH's groups typically appear around 3600-3200 and it isn't on the shown spectrum, it isn't present in the Biodiesel right?

[Violagirl]

Ok so have one more question. I have to determine the IR spectrums of three structural isomers of 4-methoxyacetopheone. One is in the form of H3C-Ar-C=O-OCH3 and the other H3C-Ar-O-C=O-CH3.

Hope you know what I mean. In the the first arrangement, the aromatic compound is directly attached to the C. The C is double bonded to an O and single bonded to an O attached to a CH3 group. In the second arrangement, the aromatic compound is attached to an O which is attached to a C. Then the C is double bonded to an O and a methyl group. My question, what's the difference in arrangement between the two? Do both contain esters? If so, how I do I figure out the difference between their IR spectrums? We have to match the spectrum to the isomer and these two have been giving me a hard time lol. 

[napoleon79]

For the first spectrum, we prepared a solid sample of 4-methoxyacetopheone and a methylene chloride solvent was added too. I got the following for possible peaks:

Between 3006-2853: C-H stretch

1601: Aromatic, C=C stretch

1739:
Ketone: C=O
Ester: C=O?

1460-1340: Alkane, C-H bond

1258, 835, 1418, 2926-methylene chloride


For the second spectrum of biodiesel:

3008:
Alkene, =C-H stretch

3008-2854:
Carboxylic Acid, O-H stretch

1743:
Ketone, C=O stretch

1461-1437
Alkanes, C-H bond

If your Biodiesel had hydroxy group. Your biodiesel was not form.

First picture I think it is H3C-Ar-C=O-OCH3
C=O conjunction Ar = 1739 < C=O unconjunction = 1743

1650 - 1601 ---> C=C of Aromatic

second Picture has not peak C=C of Aromatic 1650 - 1601. And It is not OH peak.

[Violagirl]

Thanks so much for your *delete me* That helped me clear up some confusion.