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Interpreting
and explaining the
H-1 hydrogen-1 (proton) NMR spectrum of 1,3-dioxane
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©
Dr Phil Brown PhD:
Doc Brown's advanced level organic chemistry exam revision notes
suitable for students of UK A level chemistry courses & US K12 grade
11, grade 12 and AP honors chemistry courses: Molecular
spectrometry - analysing the 1H NMR spectra of 1,3-dioxane
[spectra page updated
April 3rd 2026 *]
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H-1 proton NMR spectroscopy -
spectra index
Introductory note on the 1H NMR spectra of 1,3-dioxane
Students and teachers please note my explanation of the
proton NMR spectrum of 1,3-dioxane is designed for advanced, but
pre-university, chemistry courses.
The chemical shift
δ splitting pattern effects for
1,3-dioxane are
confined to a proton spin-spin
coupling effects analysed using the n+1 rule for adjacent
non-equivalent proton fields (n is the number of neighbouring
protons in a non-equivalent different chemical environment for the
1,3-dioxane molecule).
It is assumed that the integrated intensities of the
δ
chemical shifts give the ratio of the protons in the different
non-equivalent chemical environments of the 1,3-dioxane molecule.
The most common solvent used for investigating the 1H NMR
spectrum of compounds like 1,3-dioxane , is CDCl3 and other
deuterated solvents to avoid confusion with a 1H NMR
signal, 2D (2H) has a different chemical
shift.
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 resonances, called chemical shifts, are measured
with respect to the TMS, and depend on the
individual (electronic) chemical environment of the hydrogen atoms
in an organic molecule - 1,3-dioxane here.
The chemical shifts quoted in ppm on the diagram of
the H-1 NMR spectrum of 1,3-dioxane 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 1,3-dioxane molecule.
 Interpreting the
H-1 NMR spectrum of
1,3-dioxane
In terms of spin-spin coupling from the possible proton magnetic orientations,
for 1,3-dioxane I
have only considered the interactions of
non-equivalent protons on adjacent carbon atoms
e.g. R-CH2-CH2-X,
protons.
For relatively simple molecules, the low
resolution H-1 NMR spectrum of 1,3-dioxane is a good starting point
(low resolution diagram above).
The hydrogen atoms (protons) of 1,3-dioxane occupy
3
different chemical environments so that the low resolution NMR
spectra should show 3 principal
1H peaks of different H-1 NMR chemical shifts
in the proton ratio of 2:4:2, observed as an integrated proton
ratio of 1:2:1 (diagram above for
1,3-dioxane).
Chemical shifts (a) to (c) on the H-1 NMR
spectrum diagram for 1,3-dioxane.
Although there are 8 hydrogen atoms in the molecule,
there are only 3 possible different chemical
environments for the hydrogen atoms in 1,3-dioxane molecule.
The integrated signal proton ratio 1:2:1 observed
in the high resolution H-1 NMR spectrum, corresponds with
the structural formula of 1,3-dioxane.
The high resolution 1H NMR
spectrum of 1,3-dioxane
The high resolution spectra of 1,3-dioxane
shows 3 groups of proton resonances and in the 1:2:1 ratio expected from the
structural
formula of 1,3-dioxane.
The ppm quoted on the diagram represent the peak
of resonance intensity for a particular proton group in the
molecule of 1,3-dioxane - since the peak' is at the apex of a band of
H-1 NMR resonances due to spin - spin coupling field splitting effects - see high resolution
notes on 1,3-dioxane below.
So, using the chemical shifts and applying the
n+1 rule to
1,3-dioxane
and make some predictions using some colour coding! (In problem
solving you work the other way round!)
(a) 1H
Chemical shift 1.78 ppm, CH2 protons furthest from the oxygen
atoms
This resonance is split into a 1:4:6:4:1
quintet by the adjacent CH2 protons on either
side (n+1 = 5).
Evidence for the presence of a CH2-CHx-CH2 grouping
in the molecule of 1,3-dioxane
(b) 1H
Chemical shift 3.91 ppm, 2 x CH2 protons nearest on either
side of the oxygen atoms
This resonance is split by the adjacent
CH2 protons into a 1:2:1 triplet (n+1 = 3)
Evidence for the presence of a 2nd CH2 group
in the molecule of 1,3-dioxane
(c) 1H
Chemical shift 4.85 ppm, CH2 protons between the oxygen
atoms.
This resonance is not split because
there are no protons on an adjacent atom, these protons
are 'isolated' between the oxygen atoms.
From the proto ratio and molecular
formula, gives evidence for the presence of a 3rd group
of CH2 protons in the molecule of 1,3-dioxane
The splitting pattern from proton
spin-spin coupling effects is analysed using the n+1 rule for
adjacent non-equivalent proton fields (n is the number of
neighbouring protons in a non-equivalent different chemical
environment) and applied to the 1H NMR spectrum of
1,3-dioxane .
|
Number of directly adjacent protons 1H
causing splitting |
Splitting pattern produced from the
n+1 rule on spin-spin coupling 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:
C4H8O2
Interpreting the proton H-1 NMR spectra of 1,3-dioxane, low resolution & high resolution proton
nmr spectra of 1,3-dioxane, H-1 nmr spectrum of 1,3-dioxane, understanding the
hydrogen-1 nmr spectrum of 1,3-dioxane, explaining the line splitting patterns from
spin-spin coupling in the
high resolution H-1 nmr spectra of 1,3-dioxane, revising the H-1 nmr spectrum of
1,3-dioxane,
proton nmr of 1,3-dioxane, ppm chemical shifts of the H-1 nmr spectrum of
1,3-dioxane,
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 1,3-dioxane, how to work out the
number of chemically different protons in the structure of the 1,3-dioxane organic
molecule, how to analyse the chemical shifts in the hydrogen-1 H-1 proton NMR
spectrum of 1,3-dioxane using the n+1 rule to explain the spin - spin coupling ine
splitting in the proton nmr spectrum of 1,3-dioxane deducing the nature of the protons
from the chemical shifts ppm in the H-1 nmr spectrum of 1,3-dioxane
examining the 1H nmr spectrum of 1,3-dioxane analysing the 1-H nmr spectrum of
1,3-dioxane
how do you sketch and interpret the H-1 NMR spectrum of 1,3-dioxane interpreting
interpretation of the 1H proton spin-spin coupling causing line splitting in the
NMR spectrum of 1,3-dioxane
assignment of chemical shifts in the
proton 1H NMR spectrum of 1,3-dioxane formula explaining spin-spin coupling for
line splitting for 1,3-dioxane meta-dioxane m-dioxane
ether functional group
How do you interpret the H-1 NMR spectrum of
1,3-dioxane How to interpret
the H-1 NMR spectrum of 1,3-dioxane Explanatory diagram of the chemical
shifts of the 1H H-1 proton NMR spectrum of the 1,3-dioxane
molecule in terms of its molecular structure. Listing data of all the chemical shift peaks in ppm in the
proton NMR spectrum of 1,3-dioxane . How to explain the H-1 NMR spectrum of
1,3-dioxane . The chemical shifts and integrated values of the proton ratios in the 1-H NMR
spectrum of the 1,3-dioxane molecule. How to work out the molecular
structure of the 1,3-dioxane molecule from its proton NMR spectrum. The uses
and distinctive features of the proton NMR spectrum of the
1,3-dioxane
molecule explained. What does the H-1 proton NMR spectrum chemical
shifts tell us about the
structure and properties of the 1,3-dioxane
molecule? explaining the spin-spin proton coupling effects in the 1H
NMR spectrum of 1,3-dioxane . interpretation
diagram explaining the proton splitting pattern produced from the
n+1 rule and the theoretical ratio of chemical shift
δ and values of
intensities for the proton NMR spectrum lines of 1,3-dioxane
Links associated
with
1,3-dioxane
The infrared spectrum of 1,2-dioxane (a
cyclic peroxide), not available?
The infrared spectrum of 1,3-dioxane (a cyclic ether)
The infrared spectrum of 1,4-dioxane (a cyclic ether)
The mass spectrum of 1,2-dioxane (a
cyclic peroxide), not available?
The mass spectrum of 1,3-dioxane (a cyclic ether)
The mass spectrum of 1,4-dioxane (a cyclic ether)
The H-1
spectrum of 1,2-dioxane (a cyclic peroxide)
The H-1
spectrum of 1,3-dioxane (a cyclic ether)
The H-1
spectrum of 1,4-dioxane (a cyclic ether)
The C-13
spectrum of 1,2-dioxane (a cyclic peroxide)
The C-13
spectrum of 1,3-dioxane (a cyclic ether)
The C-13
spectrum of 1,4-dioxane (a cyclic ether)
H-1 proton NMR spectroscopy index
(Please
read 8 points at the top of the 1H NMR index page)
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