Bertybassett
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Hi, I was wondering if someone could please help me with some questions from this nmr paper. Firstly, i'm slightly confused on the meaning of integration traces - how are these used? For 1a.), how do you find the c13 value for the c at a. For 3cii.) how and why is this nucleophilic addition elimination - how is this worked out? For 3d. im struggling to workout the structure. For 3eii, the answer is 12 but wouldn't it be 10 as two groups attached to the "central" c are the same (the c6h5oh groups)? Many thanks https://pmt.physicsandmathstutor.com...y%202%20QP.pdf
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username3249896
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1a) C next to C=O, 20-50 ppm according to the table C of the data sheet
https://filestore.aqa.org.uk/resourc...A-7405-SDB.PDF

3c) It is esterification which is a condensation reaction. It is a nucleophilic addition-elimination reaction. Addition occurs first then elimination so addition-elimination. The nature of the attacking species is nucleophile so nucleophilic addition elimination
https://www.chemguide.co.uk/organicp...es/oxygen.html

3d) Similar to reaction with water, instead of H-O-H you have H-O-CH3. So you have the C-O bond breaking, then you get COOH and COOCH3 groups

https://imgur.com/a/uTz3x79
i showed C in the same environment by same number
total is 12

Your reasoning for 10 peaks is unclear.
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Bertybassett
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Hi, thanks for the reply. For 3d I am still unclear on. What would the reaction with h2o be in the first place? Also, for the question countin the number of carbon environments, surely the two benzene rings on the "right hand side" are both in exactly the same environment. Like when there are two methyl groups attached to the same c in a molecule, both carbons are in the same environment in some cases. Therefore i'm struggling to understand why we count the number of carbon environments in both of these "benzene rings" and adding them together instead of just using one?
(Original post by BobbJo)
1a) C next to C=O, 20-50 ppm according to the table C of the data sheet
https://filestore.aqa.org.uk/resourc...A-7405-SDB.PDF

3c) It is esterification which is a condensation reaction. It is a nucleophilic addition-elimination reaction. Addition occurs first then elimination so addition-elimination. The nature of the attacking species is nucleophile so nucleophilic addition elimination
https://www.chemguide.co.uk/organicp...es/oxygen.html

3d) Similar to reaction with water, instead of H-O-H you have H-O-CH3. So you have the C-O bond breaking, then you get COOH and COOCH3 groups

https://imgur.com/a/uTz3x79
i showed C in the same environment by same number
total is 12

Your reasoning for 10 peaks is unclear.
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username3249896
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(Original post by Bertybassett)
Hi, thanks for the reply. For 3d I am still unclear on. What would the reaction with h2o be in the first place? Also, for the question countin the number of carbon environments, surely the two benzene rings on the "right hand side" are both in exactly the same environment. Like when there are two methyl groups attached to the same c in a molecule, both carbons are in the same environment in some cases. Therefore i'm struggling to understand why we count the number of carbon environments in both of these "benzene rings" and adding them together instead of just using one?
3d) An acid anhydride (RCO)2O + H2O -> 2RCOOH
It is in the second link I gave to you https://www.chemguide.co.uk/organicp...es/oxygen.html
The general case H-O-X is given too

A benzene ring contains 6 carbon atoms. Look at the picture I linked https://imgur.com/a/uTz3x79
carbon atoms 9 are in identical environments
so are carbon atoms 10,11,12

The carbon atoms in a single benzene ring itself are not in identical environments. Look at the surrounding groups on each carbon atom
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