loooooooooool0
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One question I have :

A carbon-13 NMR spectrum of an alcohol with molecular formula C4 H10 O

It has three peaks so 3 different carbon enviroments. I thought it would be butan-2-ol but mark scheme says 2-methyl-propan-1-ol.

One peak at 65, two at 20.

Explain why thanks x
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Nuttyy
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Need to know where the peaks are. Send the entire Q
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loooooooooool0
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One is at 65, and two at 20.
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Appazap
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(Original post by loooooooooool0)
I tend to find NMR Spec questions difficult when working out molecular structures.

One question I have :

A carbon-13 NMR spectrum of an alcohol with molecular formula C4 H10 O2

It has three peaks so 3 different carbon enviroments. I thought it would be butan-2-ol but mark scheme says 2-methyl-propan-2-ol.

Explain why thanks x
edit: is it a diol?
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loooooooooool0
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(Original post by Appazap)
have you looked at the splitting pattern
It's C NMR not high res? They're all singlets?
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loooooooooool0
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(Original post by Appazap)
edit: is it a diol?
nah
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yazoo12uk
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what spec you doing
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loooooooooool0
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#8
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(Original post by yazoo12uk)
what spec you doing
edexcel
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Appazap
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I think butan-2-ol has 4 carbon enviornments?
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wantodothebest
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#10
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I got 3 methyl propanol not 2 methyl
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wantodothebest
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#11
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Wait not I got 2... you always read from the alcohol group right?
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FP5
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(Original post by Appazap)
have you looked at the splitting pattern
Splitting pattern only applies to proton NMR.

As for your question, if there are three peaks then there are 3 carbon environments.

Peak at 65 shows the presence of a C-O bond.
Peaks at roughly 20 show presence C-C bonds.

If the answer says that it is 2-methyl-propan-2-ol, then it cannot have the molecular formula of C4H10O2, as there is only one oxygen atom in 2-methyl-propan-2-ol.

Please post or provide a link to the question, thanks.
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loooooooooool0
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(Original post by FP5)
Splitting pattern only applies to proton NMR.

As for your question, if there are three peaks then there are 3 carbon environments.

Peak at 65 shows the presence of a C-O bond.
Peaks at roughly 20 show presence C-C bonds.

If the answer says that it is 2-methyl-propan-2-ol, then it cannot have the molecular formula of C4H10O2, as there is only one oxygen atom in 2-methyl-propan-2-ol.

Please post or provide a link to the question, thanks.
sorry I meant one O. and it's within my CGP edexcel book, page 233
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yazoo12uk
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Can u send the full question cuz u might be missing something
The molecular formula is C4 H10 02
But the answer only gives one oxygen
Did you calculate the molecular formula yourself cuz c4 h10 02 is the characteristic general formula of carboxylic acid
Are u sure its not c4 h10 0 or C4 H9 0H
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loooooooooool0
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#15
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(Original post by yazoo12uk)
Can u send the full question cuz u might be missing something
The molecular formula is C4 H10 02
But the answer only gives one oxygen
sorry I mistyped, it ways C4 H10 O
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FP5
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(Original post by loooooooooool0)
sorry I meant one O. and it's within my CGP edexcel book, page 233
Sorry that doesn't help me because I don't have the textbook

Any chance you could post a picture of the question?
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marupe
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(Original post by Appazap)
I think butan-2-ol has 4 carbon enviornments?
exactly. 2-methylpropan-1-ol has two carbons in the same environment (the two end carbons) which will give a peak at 20, the middle carbon attached to these also at 20ppm and the C-O carbon at ~65ppm
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Appazap
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(Original post by marupe)
exactly. 2-methylpropan-1-ol has two carbons in the same environment (the two end carbons) which will give a peak at 20, the middle carbon attached to these also at 20ppm and the C-O carbon at ~65ppm
yeah 2-methylpropan-1-ol does make sense
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