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Advanced Organic Chemistry: Carbon-13 NMR spectrum of methoxyethane

Interpreting the Carbon-13 NMR spectrum of methoxyethane

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 methoxyethane

See also comparing the infrared, mass, 1H NMR and 13C NMR spectra of the 3 isomers of C3H8O

C3H8O CH3OCH2CH3 C-13 nmr spectrum of methoxyethane analysis of chemical shifts ppm interpretation of 13C chemical shifts ppm of ethyl methyl ether C13 13-C nmr doc brown's advanced organic chemistry revision notes 

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 resonances, called chemical shifts, are measured with respect to the TMS, and depend on the individual (electronic) chemical environment of the 13C atoms in an organic molecule - methoxyethane here.

Methoxyethane  alcohols and ether structure and naming (c) doc b  alcohols and ether structure and naming (c) doc b  alcohols and ether structure and naming (c) doc b  alcohols and ether structure and naming (c) doc b

Interpreting the C-13 NMR spectrum of methoxyethane

As you can see from the diagram above there are 3 different chemical shift lines in the C-13 NMR spectrum of methoxyethane indicating 3 different chemical environments of the 3 carbon atoms of methoxyethane.

CH3OCH2CH3

(Note the 3 different colours indicating the 3 different chemical environments of the carbon atoms in methoxyethane).

13C chemical shifts (a) to (c) on the C-13 NMR spectrum diagram for methoxyethane.

Note the decreasing effect on the 13C chemical shift as the carbon atom is further from the more electronegative oxygen atom methoxyethane.

The carbon-13 NMR spectra provides direct evidence of 3 different carbon atom environments for the 3 carbon atoms in the methoxyethane molecule, deduced from the presence of 3 different 13C 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.

infrared spectrum of ethoxyethane wavenumbers cm-1 functional group detection fingerprint pattern identification of  diethyl ether doc brown's advanced organic chemistry revision notes 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 chemical shift lines. You would need other spectral data to distinguish propan-1-ol and methoxyethane. Two of ethoxyethane's 13C resonances are shifted to higher values due to the influence of the more electronegative oxygen atom (only one large shift for the other two molecules).

Key words & phrases: C3H8O CH3OCH2CH3 Interpreting the C-13 NMR spectra of methoxyethane, C-13 nmr spectrum of methoxyethane, understanding the carbon-13 nmr spectrum of methoxyethane, explaining the line pattern in the high resolution C-13 nmr spectra of methoxyethane, revising the C-13 nmr spectrum of methoxyethane, ppm chemical shifts of the C-13 nmr spectrum of methoxyethane, how to construct the diagram of the C-13 nmr spectrum of methoxyethane, how to analyse the chemical shifts in the carbon-13 NMR spectrum of methoxyethane deducing the chemical environment of all the carbon atoms in methoxyethane examining the c13 nmr spectrum of  methoxyethane analysing the 13-c nmr spectrum of methoxyethane how do you sketch and interpret the C-13 NMR spectrum of methoxyethane interpreting interpretation of the C-13 NMR spectrum of methoxyethane assignment of chemical shifts in the 13C NMR for ethyl methyl ether spectrum of methoxyethane methyl ethyl ether CH3CH2OCH3

isomer of molecular formula C3H8O Molecular structure diagram of the carbon-13 NMR diagram for the 13C NMR spectrum of methoxyethane. Deducing the number of different chemical environments of the carbon atoms in the methoxyethane molecule from the 13C chemical shifts in the carbon-13 NMR spectrum of methoxyethane. Revision notes on the carbon-13 NMR spectrum of methoxyethane. Matching and deducing the structure of the methoxyethane molecule from its 13C NMR spectrum. Carbon-13 NMR spectroscopy of aliphatic ethers, 13C NMR spectra of methoxyethane, an isomer of molecular formula C3H8O


Links associated with methoxyethane

The infrared spectrum of methoxyethane

The mass spectrum of methoxyethane

The H-1 NMR spectrum of methoxyethane

C-13 NMR spectroscopy index

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