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Interpreting the
1H NMR spectrum of 1-chloro-2-methylpropane
[Author
©
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
spectroscopy - analysing the
H-1 NMR spectrum of 1-chloro-2-methylpropane
[updated
Mar 11th 2026 *]
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Re-edit
1H NMR spectrum of
(CH3)2CHCH2Cl
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H-1 proton NMR spectroscopy -
spectra index
See also
Comparing infrared, mass, 1H NMR & 13C NMR
spectra of the 4 structural isomers of C4H9Cl
Introductory note on the 1H NMR spectra of 1-chloro-2-methylpropane
Students and teachers please note my explanation of the
proton NMR spectrum of 1-chloro-2-methylpropane is designed for advanced, but
pre-university, chemistry courses.
The chemical shift
δ splitting pattern effects for
1-chloro-2-methylpropane 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-chloro-2-methylprpane 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-chloro-2-methylpropane molecule.
The most common solvent used for investigating the 1H NMR
spectrum of compounds like 1-chloro-2-methylpropane, 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-chloro-2-methylpropane here.
The chemical shifts quoted in ppm on the diagram of
the H-1 NMR spectrum of 1-chloro-2-methylpropane 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-chloro-2-methylpropane molecule.
 ,
 ,
 ,
 ,
1-chloro-2-methylpropane
For more see
Molecular structure, classification and
naming of
halogenoalkanes (haloalkanes)
Interpreting the
H-1 NMR spectrum of 1-chloro-2-methylpropane
In terms of spin-spin coupling from the possible proton magnetic orientations,
for 1-chloro-2-methylpropane I
have only considered the interactions of
non-equivalent protons on adjacent carbon atoms
e.g. -CH2-CH<
For relatively simple molecules, the
low
resolution H-1 NMR spectrum of 1-chloro-2-methylpropane is a
good starting point which will show 3 groups of protons in the
ratio 6:1:2.
The hydrogen atoms (protons) of
1-chloro-2-methylpropane occupy 3
different chemical environments so that the low/high resolution NMR
spectra should show 3 principal peaks of different H-1 NMR chemical shifts (diagram above for
1-chloro-2-methylpropane).
(CH3)2CHCH2Cl
Note the
proton ratio 6:1:2 of the 3 colours of the protons
in the 3 chemically different environments
Chemical shifts
(a) to (c) on the H-1 NMR
spectrum diagram for 1-chloro-2-methylpropane.
Although there are 9 hydrogen atoms in the molecule,
there are only 3 possible different chemical
environments for the hydrogen atoms in 1-chloro-2-methylpropane molecule.
The integrated signal proton ratio
6:1:3 observed
in the high resolution H-1 NMR spectrum, corresponds with
the structural formula of 1-chloro-2-methylpropane.
The high resolution 1H NMR
spectrum of 1-chloro-2-methylpropane
All low and high resolution spectra of
1-chloro-2-methylpropane
show ? groups of proton resonances and in the ? ratio expected from the
formula of 1-chloro-2-methylpropane.
The ppm quoted on the diagram represent the peak
of resonance intensity for a particular proton group in the
molecule of 1-chloro-2-methylpropane - 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-chloro-2-methylpropane below.
So, using the chemical shifts and applying the
n+1 rule to
1-chloro-2-methylpropane
and make some predictions using some colour coding! (In problem
solving you work the other way round!)
(a)
1H
Chemical shift 1.01 ppm, 2 x CH3 protons : (CH3)2CHCH2Cl
This 1H resonance is split by the
adjacent CH
proton into a 1:1 doublet (n+1 = 2).
Evidence for the presence of a CH group
in the molecule of 1-chloro-2-methylpropane
(b)
1H
Chemical shift 1.95 ppm, CH proton : (CH3)2CHCH2Cl
This 1H resonance is split into a nonet
by the adjacent 2 x CH3 and CH2 protons
(n+1 = 9)
Evidence for the presence of a (CH3)2-C-CH2 group
in the molecule of 1-chloro-2-methylpropane
(c)
1H
Chemical shift 3.38 ppm, CH2 protons: (CH3)2CHCH2Cl
This 1H resonance is split by the
adjacent CH
proton into a 1:1 doublet (n+1 = 2).
Evidence for the presence of a CH group
in the molecule of 1-chloro-2-methylpropane
Note the decreasing effect on the
1H chemical shift as the
proton is further from the more electronegative chlorine atom in 1-chloro-2-methylpropane.
Summary of the
1H NMR proton spectrum of 1-chloro-2-methylpropane and extra comments
The ¹H NMR spectrum of 1-chloro-2-methylpropane
(isobutyl chloride) with precision and exam clarity.
Structural
Overview
of 1-chloro-2-methylpropane
Molecular formula: C4H9Cl
Key proton environments:
- One CH2 group adjacent to Cl
- One CH group bonded to two methyls
- Two CH3 groups (methyl branches)
Proton
Chemical Shifts Table
for the 1H NMR spectrum of 1-chloro-2-methylpropane
|
Chemical Shift (δ, ppm) |
Proton Type |
Environment |
Proton
Integration |
Splitting Pattern |
Origin |
| ~3.4, 3.38
ppm |
CH2 |
Adjacent to Cl (–CH2Cl) |
2H |
Doublet |
Deshielded by electronegative
Cl |
| ~1.9, 1.95
ppm |
CH |
Central carbon bonded to two
CH3 and a CH2 |
1H |
Multiplet, nonet
via n+1 rule |
Slightly deshielded, complex
coupling |
| ~1.0, 1.01
ppm |
CH3 |
Two equivalent methyl groups |
6H |
Doublet |
Coupled to adjacent CH |
(CH3)2CHCH2Cl
Note: Exact chemical shifts may vary slightly depending on
solvent and instrument, but the relative positions and patterns
remain consistent.
Common
Misconceptions about
the 1H NMR spectrum of 1-chloro-2-methylpropane
(see also below)
- Assuming all methyls give singlets: In branched
alkanes, methyls often couple with adjacent CH, giving
doublets.
- Overlooking Cl’s effect: Chlorine causes
deshielding, shifting the CH2 peak
downfield (~3.4 ppm).
- Misassigning integration: Students may forget
that two methyls = 6H, not 3H for the same chemical
shift.
Exam Tips
for questions involving
the 1H NMR spectrum of 1-chloro-2-methylpropane
(see also above)
- Start with integration: Match peak areas to
proton counts (2H, 1H, 6H).
- Use chemical shift logic: Electronegative atoms
like Cl shift nearby protons downfield.
- Annotate splitting patterns: Triplet, doublet,
multiplet — explain coupling partners.
- Compare with isomers: Tert-butyl chloride shows
a singlet for 9H — useful contrast.
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).
|
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 |
|
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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 |
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2 |
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1 |
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3
creates a quartet |
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1 |
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3 |
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3 |
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1 |
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4
creates a quintet |
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1 |
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4 |
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6 |
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4 |
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1 |
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5
creates a sextet |
|
1 |
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5 |
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10 |
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10 |
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5 |
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1 |
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6
creates a septet |
1 |
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6 |
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15 |
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20 |
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15 |
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6 |
|
1 |
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Comparing the infrared, mass, 1H NMR and 13C NMR
spectra of the 4 halogenoalkane isomers of C4H9Cl
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 1-chlorobutane,
2-chlorobutane, 1-chloro-2-methylpropane and 2-chloro-2-methylpropane
image sizes. These four molecules
are structural isomers of molecular formula C4H9Cl
and
exemplify the infrared, mass, 1H NMR and 13C NMR spectra of lower
aliphatic halogenoalkanes (haloalkanes, alkyl halides,
chloroalkanes, alkyl chlorides). |
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INFRARED SPECTRA
(above):
Apart from the significant differences in the fingerprint region at
wavenumbers 1500 to 400 cm-1, there are no other
great striking differences, but each could be identified from
its infrared spectrum. The infrared spectrum of
2-chloro-2-methylpropane is noticeably simpler in the
fingerprint region, perhaps due to
the greater symmetry of the molecule. |
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MASS SPECTRA (above):
Theoretically, all four can give the parent molecular ions of
m/z 92 and 94, but they are all relatively tiny peaks.
2-chlorobutane and 2-chloro-2-methylpropane give a base ion peak
of m/z 57. The base ion peak for 1-chlorobutane is m/z 56 and
that of 1-chloro-2-methylpropane is m/z 43. Each gives different
patterns of pairs of m/z values two mass units apart, in the
peak height ratio of 3:1, if the positive fragment contains a
chlorine atom (35Cl or 37Cl) e.g look for
m/z pairs 49/51, 63/65 and 77/79 in their mass spectra. |
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1H NMR SPECTRA
(above): The 1H NMR spectra of all four molecules give different
integrated proton ratios i.e.1-chlorobutane
four peaks of ratio 3:2:2:2; 2-chlorobutane four peaks of
ratio 3:3:2:1,
1-chloro-2-methylpropane three peaks of ratio 6:2:1 and
2-chloro-2-methylpropane gives just one peak '1' (effectively no ratio
involved), so all four molecular structures can be distinguished from each other by their
1H NMR spectra proton ratios, numbers of peaks and (n+1)
rule splitting patterns. |
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13C NMR SPECTRA
(above): The
13C NMR spectra of the four molecules show various numbers of
carbon-13 chemical environments i.e 1-chlorobutane and
2-chlorobutane show four 13C NMR resonances,
1-chloro-2-methylpropane three 13C NMR resonances and
2-chloro-2-methylpropane only two 13C resonances (3 and 2
chemical environments respectively. Therefore
1-chloro-2-methylpropane and 2-chloro-2-methylpropane can be
distinguished from the other three by their number of resonances
in their 13C NMR spectra, but 1-chlorobutane and 2-chlorobutane
cannot be distinguished from each other from their number of 13C
NMR resonance lines - other data would be required. |
Key words & phrases:
C4H9Cl
(CH3)2CH2Cl
Interpreting the proton H-1 NMR spectra of 1-chloro-2-methylpropane, low resolution & high resolution proton
nmr spectra of 1-chloro-2-methylpropane, H-1 nmr spectrum of
1-chloro-2-methylpropane, understanding the
hydrogen-1 nmr spectrum of 1-chloro-2-methylpropane, explaining the line splitting patterns from
spin-spin coupling in the
high resolution H-1 nmr spectra of 1-chloro-2-methylpropane, revising the H-1 nmr spectrum of
1-chloro-2-methylpropane,
proton nmr of 1-chloro-2-methylpropane, ppm chemical shifts of the H-1 nmr spectrum of
1-chloro-2-methylpropane,
explaining and analyzing spin line splitting in the H-1 nmr spectrum, how
to construct the diagram of the H-1 nmr spectrum of 1-chloro-2-methylpropane, how to work out the
number of chemically different protons in the structure of the
1-chloro-2-methylpropane organic
molecule, how to analyse the chemical shifts in the hydrogen-1 H-1 proton NMR
spectrum of 1-chloro-2-methylpropane using the n+1 rule to explain the spin - spin coupling splitting in the proton nmr spectrum of 1-chloro-2-methylpropane deducing the nature of the protons
from the chemical shifts ppm in the H-1 nmr spectrum of 1-chloro-2-methylpropane
examining the 1H nmr spectrum of 1-chloro-2-methylpropane analysing the 1-H nmr spectrum of
1-chloro-2-methylpropane how do you sketch and interpret the H-1 NMR spectrum of
1-chloro-2-methylpropane
interpreting interpretation of the 1H proton spin-spin coupling causing line
splitting in the NMR spectrum of 1-chloro-2-methylpropane
assignment of chemical shifts in the
proton 1H NMR spectrum of 1-chloro-2-methylpropane formula explaining spin-spin coupling for line splitting
of isobutyl
chloride Molecular structure diagram of the
proton NMR diagram for the 1H NMR spectrum of 1-chloro-2-methylpropane. The proton ratio in the
1H NMR spectrum of 1-chloro-2-methylpropane. Deducing the number of different chemical
environments of the protons in the 1-chloro-2-methylpropane molecule from the 1H chemical shifts
in the hydrogen-1 NMR spectrum of 1-chloro-2-methylpropane. Analysing the high resolution 1H NMR
spectrum of 1-chloro-2-methylpropane. Analysing the low resolution 1H NMR spectrum of
1-chloro-2-methylpropane. You
may need to know the relative molecular mass of 1-chloro-2-methylpropane to deduce the molecular
formula from the proton ratio of the 1H NMR spectrum of
1-chloro-2-methylpropane. Revision notes
on the proton NMR spectrum of 1-chloro-2-methylpropane. Matching and deducing the structure of
the 1-chloro-2-methylpropane molecule from its hydrogen-1 NMR spectrum.
Proton NMR spectroscopy of aliphatic
halogenoalkanes haloalkanes alkyl halides alkyl chlorides chloroalkanes,
1H NMR spectra of 1-chloro-2-methylpropane, an isomer of molecular formula
C4H9ClHow do you interpret the H-1 NMR
spectrum of 1-chloro-2-methylpropane How to interpret the H-1 NMR spectrum of
1-chloro-2-methylpropane Explanatory diagram of the chemical shifts of the 1H
H-1 proton NMR spectrum of the 1-chloro-2-methylpropane molecule in terms of its
molecular structure. Listing data of all the chemical shift peaks in ppm in the
proton NMR spectrum of 1-chloro-2-methylpropane. How to explain the H-1 NMR
spectrum of 1-chloro-2-methylpropane. The chemical shifts and integrated
values of the proton ratios in the 1-H NMR spectrum of the
1-chloro-2-methylpropane molecule. How to work out the molecular structure of
the 1-chloro-2-methylpropane molecule from its proton NMR spectrum. The uses and
distinctive features of the proton NMR spectrum of the 1-chloro-2-methylpropane
molecule explained. What does the H-1 proton NMR spectrum chemical shifts tell
us about the structure and properties of the 1-chloro-2-methylpropane molecule?
Links associated
with
1-chloro-2-methylpropane
The chemistry of HALOGENOALKANES (haloalkanes)
revision notes INDEX
The infrared
spectrum of 1-chloro-2-methylpropane (isobutyl
chloride)
The mass
spectrum of 1-chloro-2-methylpropane (isobutyl
chloride)
The C-13
NMR spectrum of 1-chloro-2-methylpropane (isobutyl
chloride)
H-1 proton NMR spectroscopy index
(Please
read 8 points at the top of the 1H NMR index page)
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All Advanced Organic
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