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The H-1
hydrogen-1 (proton) NMR spectrum of methyl methanoate
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Brown's Chemistry Advanced Level Pre-University Chemistry Revision Study
Notes for UK IB KS5 A/AS GCE advanced A level organic chemistry students US
K12 grade 11 grade 12 organic chemistry courses involving molecular
spectroscopy analysing H-1 NMR spectra of methyl methanoate
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H-1 proton NMR spectroscopy -
spectra index
See also
comparing the infrared, mass, 1H and 13C NMR spectra of
the isomers of C2H4O2
TMS is the acronym for tetramethylsilane, formula
Si(CH3)4, whose protons are arbitrarily given
a chemical shift of 0.0 ppm. This is the 'standard' in 1H
NMR spectroscopy and all other proton shifts, called chemical
shifts, depend on the individual (electronic) chemical
environment of the hydrogen atoms in an organic molecule - methyl
methanoate here.
The chemical shifts quoted in ppm on the diagram of
the H-1 NMR spectrum of methyl methanoate represent the peaks of the
intensity of the chemical shifts of (which are often groups of split
lines at high resolution) AND the relative integrated areas under
the peaks gives you the ratio of protons in the different chemical
environments of the methyl methanoate molecule.
Methyl methanoate
(methyl
formate)
C2H4O2,
 ,
,
For more see
Structure and naming of CARBOXYLIC ACIDS and DERIVATIVES,
including isomers
Interpreting the
H-1 NMR spectrum of
methyl methanoate
For relatively simple molecules, the low
or high resolution H-1 NMR spectrum of methyl methanoate
shows two peaks (diagram above).
The hydrogen atoms (protons) of methyl
methanoate occupy 2 different chemical environments so that the
low resolution NMR spectra should show 2 peaks of different H-1
NMR chemical shifts (diagram above for methyl methanoate).
HCOOCH3
Note the ratio 1:3 of the two colours of the protons
in the two chemically different environments
Although there are four hydrogen atoms in the molecule,
there only 2 possible chemical environments for the hydrogen atoms in
methyl methanoate molecule.
The integrated proton ratio integrated 1:3 ratio observed, corresponds with
the structural formula of methyl methanoate.
The two 1H chemical environments in
the methyl methanoate molecule are the methyl group protons (CH3,
3.75 ppm chemical shift) and the CH proton (8.07 ppm chemical
shift).
Neither proton resonance signal is split because
there are no protons on an adjacent carbon atom, the carbon
atoms/protons are separated by an oxygen atom.
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Number of protons 1H
causing splitting |
Splitting pattern produced from the
n+1 rule and the theoretical ratio of line intensities |
| 0
means no splitting |
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1 |
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| 1
creates a doublet |
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1 |
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1 |
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| 2
creates a triplet |
|
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|
1 |
|
2 |
|
1 |
|
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| 3
creates a quartet |
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|
1 |
|
3 |
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3 |
|
1 |
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| 4
creates a quintet |
|
|
1 |
|
4 |
|
6 |
|
4 |
|
1 |
|
|
| 5
creates a sextet |
|
1 |
|
5 |
|
10 |
|
10 |
|
5 |
|
1 |
|
| 6
creates a septet |
1 |
|
6 |
|
15 |
|
20 |
|
15 |
|
6 |
|
1 |
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Comparing the infrared, mass, 1H NMR and 13C NMR
spectra of the 2 isomers of C2H4O2
NOTE: The images are linked to their
original detailed spectral analysis pages AND can be doubled in
size with touch screens to
increase the definition to the original ethanoic acid (acetic
acid) and
methyl methanoate (methyl formate) image sizes. |
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INFRARED SPECTRA:
Apart from the significant differences in the fingerprint region at
wavenumbers 1500 to 400 cm-1, the most striking
difference is the broad O-H stretching band ~3200 cm-1,
found in the infrared spectrum of carboxylic acids, but absent in
the infrared spectrum of esters. |
 |
 |
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MASS SPECTRA: Apart
from the m/z of 60 for the parent molecular ion and m/z 15 ion [CH3]+,
both ethanoic acid and methyl methanoate show few similarities in their mass
spectra. Their base ion peaks are quite different - for ethanoic
acid it is m/z 43 and for methyl methanoate it is m/z 31. |
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1H NMR SPECTRA: The 1H NMR spectra of
ethanoic acid and methyl methanoate are similar with two
'wide-apart' chemical shift singlet peaks in the
integrated proton ratio of 3:1 (meaning 2 different
1H chemical environments). However, although no
splitting is observed, the 1H chemical shifts for the
two molecules are different, those of methyl methanoate are much
closer together. |
 |
 |
|
13C NMR SPECTRA: The 13C NMR spectra of
ethanoic acid and methyl methanoate are similar, both molecules give two
C-13 NMR spectral lines (meaning 2
different 13C chemical environments). |
Key words & phrases:
methyl formate Interpreting the proton H-1 NMR spectra of methyl
methanoate, low resolution & high resolution proton nmr spectra of methyl
methanoate, H-1 nmr spectrum of methyl methanoate, understanding the hydrogen-1
nmr spectrum of methyl methanoate, explaining the line splitting patterns in the
high resolution H-1 nmr spectra of methyl methanoate, revising the H-1 nmr
spectrum of methyl methanoate, proton nmr of methyl methanoate, ppm chemical
shifts of the H-1 nmr spectrum of methyl methanoate, explaining and analyzing
spin spin line splitting in the H-1 nmr spectrum, how to construct the diagram
of the H-1 nmr spectrum of methyl methanoate, how to work out the number of
chemically different protons in the structure of the methyl methanoate organic
molecule, how to analyse the chemical shifts in the hydrogen-1 H-1 proton NMR
spectrum of methyl methanoate using the n+1 rule to explain the spin - spin
coupling ine splitting in the proton nmr spectrum of methyl methanoate deducing
the nature of the protons from the chemical shifts ppm in the H-1 nmr spectrum
of methyl methanoate examining the 1H nmr spectrum of methyl methanoate
analysing the 1-H nmr spectrum of methyl methanoate how do you sketch and
interpret the H-1 NMR spectrum of methyl methanoate
interpreting interpretation of the H-1 proton NMR spectrum of methyl methanoate
methyl formate Molecular structure diagram of the
proton NMR diagram for the 1H NMR spectrum of methyl methanoate. The proton ratio in the
1H NMR spectrum of methyl methanoate. Deducing the number of different chemical
environments of the protons in the methyl methanoate molecule from the 1H chemical shifts
in the hydrogen-1 NMR spectrum of methyl methanoate. Analysing the high resolution 1H NMR
spectrum of methyl methanoate. Analysing the low resolution 1H NMR spectrum of
methyl methanoate. You
may need to know the relative molecular mass of methyl methanoate to deduce the molecular
formula from the proton ratio of the 1H NMR spectrum of methyl methanoate. Revision notes
on the proton NMR spectrum of methyl methanoate. Matching and deducing the structure of
the methyl methanoate molecule from its hydrogen-1 NMR spectrum.
Proton NMR spectroscopy of esters, 1H NMR spectra of methyl methanoate, an
isomer of molecular formula C2H4O2
Links
associated with methyl methanoate
The chemistry of CARBOXYLIC ACIDS and DERIVATIVES
revision notes INDEX
H-1 proton NMR spectroscopy
index
(Please
read 8 points at the top of the 1H NMR index page)
ALL SPECTROSCOPY INDEXES
All Advanced Organic Chemistry Notes
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