|
The Carbon-13 NMR spectrum of propan-2-ol (2-propanol)
CH3CH(OH)CH3
(re-edit)
Doc
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 C-13 NMR spectra of propan-2-ol
Use your
mobile phone in 'landscape' mode?
C-13
NMR spectroscopy - spectra index
Links associated with propan-2-ol
See also
comparing the infrared, mass, 1H NMR and 13C NMR
spectra of the 3 isomers of C3H8O
TMS is the acronym for tetramethylsilane, formula Si(CH3)4,
whose 13C atoms are arbitrarily given a chemical shift of 0.0
ppm. This is the 'standard' in 13C NMR spectroscopy and all other
13C shifts, called chemical shifts, depend on the
individual (electronic) chemical environment of the 13C atoms in
an organic molecule - propan-2-ol here.
Propan-2-ol C3H8O,
,
,
 ,
Interpreting the C-13 NMR
spectrum of propan-2-ol (2-propanol,
isopropyl alcohol)
As you can see from the diagram above there are
2 different chemical shift lines in the C-13 NMR spectrum of
propan-2-ol
indicating 2 different chemical environments of the 3 carbon atoms.
(CH3)2CHOH
or
CH3CH(OH)CH3
(Note the 2 colours indicating the
2 different chemical environment of the carbon atoms in propan-2-ol).
The carbon atoms of the methyl groups i.e.
inhabit the same 13C chemical environment in
propan-2-ol.
Note the decreasing effect on the chemical shift as the
carbon atom is further from the highly electronegative oxygen atoms of propan-2-ol.
The carbon-13 NMR spectra a provides direct evidence of
2 different
carbon atom environments in the propan-2-ol molecule from 2 different chemical
shifts (ppm).
|
Comparing the infrared, mass, 1H NMR and 13C NMR
spectra of the 3 isomers of C3H8O
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 propan-1-ol,
propan-2-ol and methoxyethane image sizes. |
 |
 |
 |
I wasn't able to obtain an infrared
spectrum for methoxyethane, so I've added the infrared spectrum
of ethoxyethane to enable a few comparisons with two aliphatic
alcohols
Comparing the
infrared
spectra of
propan-1-ol,
propan-2-ol and
methoxyethane
Propan-1-ol,
propan-2-ol and methoxyethane
are structural isomers of molecular formula C3H8O
Propan-1-ol,
propan-2-ol and methoxyethane
exemplify infrared spectra of the lower members of the homologous series
of aliphatic alcohols and ethers |
|
INFRARED SPECTRA
(above): There are, as expected, differences in the fingerprint region at
wavenumbers 1500 to 400 cm-1, but most absorptions
for all three molecules are the various C-O and the many C-H
vibrational modes. However, there is one characteristic distinguishing
absorption only present in the infrared spectra of alcohols, but
not in ethers, that is the broad O-H stretching vibration
peaking at ~3350 cm-1. There is also another broad
absorption band (origin?) peaking at ~650 cm-1 in the
alcohol spectra, but not in the ether spectra. |
 |
 |
 |
Comparing the
mass
spectra of
propan-1-ol,
propan-2-ol and
methoxyethane
Propan-1-ol,
propan-2-ol and methoxyethane
are structural isomers of molecular formula C3H8O
Propan-1-ol,
propan-2-ol and methoxyethane
exemplify the mass spectra of the lower members of the homologous series
of aliphatic alcohols and ethers |
|
MASS SPECTRA (above):
The base ion peaks are m/z 45 for propan-2-ol and methoxyethane,
but that of propan-1-ol is m/z 31. Many of the fragmentation
ions are common to all three spectra. The m/z 45 ion is peak is
much smaller in the propan-1-ol spectrum compared to the other
two. |
 |
 |
 |
Comparing the
1H proton NMR
spectra of
propan-1-ol,
propan-2-ol and
methoxyethane
Propan-1-ol,
propan-2-ol and methoxyethane
are structural isomers of molecular formula C3H8O
Propan-1-ol,
propan-2-ol and methoxyethane exemplify the 1H proton NMR spectra of
the lower members of the homologous series of aliphatic alcohols and
ethers |
|
1H NMR SPECTRA (above): The 1H NMR spectra of
all three molecules give different integrated proton ratios for the
different 1H chemical environments i.e. the proton
ratios are as follows: propan-1-ol
3:2:2:1; propan-2-ol 6:1:1 and methoxyethane
3:2:3. Therefore, all three can be distinguished by their
1H NMR spectra. |
 |
|
 |
Comparing the
carbon-13 NMR
spectra of
propan-1-ol,
propan-2-ol and
methoxyethane
Propan-1-ol,
propan-2-ol and methoxyethane
are structural isomers of molecular formula C3H8O
Propan-1-ol,
propan-2-ol and methoxyethane exemplify the carbon-13 NMR spectra of
members of the lower members of the homologous series of aliphatic
alcohols and ethers |
|
13C NMR SPECTRA
(above): The
13C NMR spectra of propan-1-ol and methoxyethane show
three different 13C NMR chemical shifts, but
propan-2-ol can be distinguished from the other two by
exhibiting only two 13C NMR chemical shift lines (the methyl
carbon atoms are in equivalent chemical environments in the
propan-2-ol molecule). You would need other spectral data to
distinguish propan-1-ol and methoxyethane. |
Key words & phrases: 2-propanol isopropyl
alcohol
Interpreting the C-13 NMR spectra of propan-2-ol, C-13 nmr spectrum of
propan-2-ol, understanding the
carbon-13 nmr spectrum of propan-2-ol, explaining the line pattern in the high
resolution C-13 nmr spectra of propan-2-ol, revising the C-13 nmr spectrum of
propan-2-ol, ppm
chemical shifts of the C-13 nmr spectrum of propan-2-ol, how to construct the diagram of
the C-13 nmr spectrum of propan-2-ol, how to analyse the chemical shifts in the
carbon-13 NMR spectrum of propan-2-ol deducing the chemical environment of all the
carbon atoms in propan-2-ol examining the c13 nmr spectrum of propan-2-ol analysing the
13-c nmr spectrum of propan-2-ol how do you sketch and interpret the C-13 NMR
spectrum of propan-2-ol 2-propanol isopropyl alcohol
isomer of molecular formula C3H8O Molecular structure diagram of the
carbon-13 NMR diagram for the 13C NMR spectrum of propan-2-ol 2-propanol. Deducing the number
of different chemical environments of the carbon atoms in the propan-2-ol
2-propanol molecule
from the 13C chemical shifts in the carbon-13 NMR spectrum of propan-2-ol
2-propanol. Revision
notes on the carbon-13 NMR spectrum of propan-2-ol 2-propanol. Matching and deducing the
structure of the propan-2-ol 2-propanol molecule from its 13C NMR spectrum.
Carbon-13 NMR spectroscopy of aliphatic alcohols,
13C NMR spectra of propan-2-ol 2-propanol, an isomer of molecular formula C3H8O Explanatory diagram of the 13C C-13 carbon-13 NMR spectrum of the propan-2-ol 2-propanol molecule in terms of its molecular structure. Listing data of all the chemical shift peaks in ppm in the carbon-13 NMR spectrum of propan-2-ol 2-propanol. How to explain the C-13 NMR spectrum of propan-2-ol 2-propanol. How to deduce the number of different carbon atom environments in the propan-2-ol 2-propanol molecule from its carbon-13 NMR spectrum to help work out the molecular structure of the propan-2-ol 2-propanol molecule. The uses and distinctive features of the carbon-13 NMR spectrum of the propan-2-ol 2-propanol molecule explained. What does the c-13 carbon-13 NMR spectrum tell us about the propan-2-ol 2-propanol molecule?
Links associated
with
propan-2-ol
The chemistry of ALCOHOLS
revision notes INDEX
The infrared spectrum of Propan-2-ol (2-propanol,
isopropyl alcohol)
The mass spectrum of Propan-2-ol (2-propanol,
isopropyl alcohol)
The H-1 NMR spectrum of Propan-2-ol (2-propanol,
isopropyl alcohol)
C-13
NMR spectroscopy index
ALL SPECTROSCOPY INDEXES
All Advanced Organic
Chemistry Notes
Use My Google search site box
Email doc b:
chem55555@hotmail.com
Website content © Dr
Phil Brown 2000+. All copyrights reserved on Doc Brown's advanced
level pre-university organic chemistry revision notes, images,
quizzes, worksheets etc. Copying of website material is NOT
permitted. Exam revision summaries and references to science course specifications
are unofficial. Please email if not happy about anything. |
