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The H-1
hydrogen-1 (proton) NMR spectrum of propanone (acetone)
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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 propanone
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H-1 proton NMR spectroscopy -
spectra index
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 - propanone here.
The chemical shifts quoted in ppm on the diagram of
the H-1 NMR spectrum of propanone 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 propanone molecule.
propanone
(acetone, dimethyl ketone), C3H6O,
 ,
 ,
 ,
Interpreting the
H-1 NMR spectrum of
propanone (acetone)
For relatively simple molecules, the low
resolution H-1 NMR spectrum of propanone is a good starting point.
The hydrogen atoms (protons) of propanone occupy
only one chemical environments so that the low resolution NMR
spectra should show just 1 peak for a H-1 NMR chemical shifts (diagram above for
propanone).
CH3COCH3
or
(CH3)2C=O
The high resolution spectrum
of propanone
All low and high resolution spectra of propanone
just
show one groups of protons and no splitting observed.
All 6 protons of propanone are equivalent to
each other i.e. they all exist in the same chemical
environment.
The C=O group separates the two groups of
methyl protons and so inhibits the spin - spin coupling,
hence no resonance line splitting, so the H-1 NMR resonance
at 2.16 ppm occurs as a singlet.
|
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 |
|
|
|
|
|
|
1 |
|
|
|
|
|
|
| 1
creates a doublet |
|
|
|
|
|
1 |
|
1 |
|
|
|
|
|
| 2
creates a triplet |
|
|
|
|
1 |
|
2 |
|
1 |
|
|
|
|
| 3
creates a quartet |
|
|
|
1 |
|
3 |
|
3 |
|
1 |
|
|
|
| 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 |
Key words & phrases: acetone
Interpreting the proton H-1 NMR spectra of propanone, low resolution & high resolution proton
nmr spectra of propanone, H-1 nmr spectrum of propanone, understanding the
hydrogen-1 nmr spectrum of propanone, explaining the line splitting patterns in the
high resolution H-1 nmr spectra of propanone, revising the H-1 nmr spectrum of
propanone,
proton nmr of propanone, ppm chemical shifts of the H-1 nmr spectrum of
propanone,
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 propanone, how to work out the
number of chemically different protons in the structure of the propanone organic
molecule, how to analyse the chemical shifts in the hydrogen-1 H-1 proton NMR
spectrum of propanone using the n+1 rule to explain the spin - spin coupling ine
splitting in the proton nmr spectrum of propanone deducing the nature of the protons
from the chemical shifts ppm in the H-1 nmr spectrum of propanone
examining the 1H nmr spectrum of propanone analysing the 1-H nmr spectrum of
propanone how do you sketch and interpret the H-1 NMR spectrum of propanone
acetone
Links associated
with propanone
The chemistry of ALDEHYDES and KETONES
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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