HOME PAGE * KS3 SCIENCES * GCSE BIOLOGY CHEMISTRY PHYSICS * ADVANCED LEVEL CHEMISTRY

SPECTROSCOPY INDEXES  *  All Advanced Organic Chemistry Notes  *  [SEARCH BOX]

Advanced Organic Chemistry: Mass spectrum of methyl methanoate

The mass spectrum of methyl methanoate

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 mass spectra of methyl methanoate

See also comparing the infrared, mass, 1H and 13C NMR spectra of the isomers of C2H4O2

mass spectrum of methyl methanoate fragmentation pattern of m/z m/e ions for analysis and identification of methyl formate image diagram doc brown's advanced organic chemistry revision notes 

Methyl methanoate (methyl formate) C2H4O2(c) doc b , (c) doc b , (c) doc b

For more see Structure and naming of CARBOXYLIC ACIDS and DERIVATIVES, including isomers

Interpreting the fragmentation pattern of the mass spectrum of methyl methanoate

[M]+ is the molecular ion peak (M) with an m/z of 60 corresponding to [C2H4O2]+, the original methyl methanoate molecule minus an electron, [HCOOCH3]+.

The minute M+1 peak at m/z 61, corresponds to an ionised methyl methanoate molecule with one 13C atom in it i.e. an ionised methyl methanoate molecule of formula 13C12CH4O2

Carbon consists of ~1% 13C atoms, ethanoic acid has 2 carbon atoms, so about 1 in 50 molecules or fragments may contain a carbon-13 atom.

Identifying the species giving the most prominent peaks (apart from M) in the fragmentation pattern of methyl methanoate.

Parent molecular ion: [HCOOCH3]+

m/z value of [fragment]+ 32 ? 31 30 29 28 15
[molecular fragment]+ [CH4O]+ [H3CO]+ [H2C=O]+ [CHO]+ [CO]+ [CH3]+

Analysing and explaining the principal ions in the fragmentation pattern of the mass spectrum of methyl methanoate

Atomic masses: H = 1;  C = 12;  O = 16

Bond enthalpies = kJ/mol: C-H = 412;  C-O = 360;  C=O  = 743

Possible equations to explain the most abundant ion peaks of methyl methanoate

Formation of m/z 31 ion:

[HCOOCH3]+  ===>  [H3CO]+  +  HCO

C-O bond scission of the parent molecular ion, mass change 60 - 29 = 31.

The m/z 31 ion is the base peak ion, the most abundant and 'stable' ion fragment.

Formation of m/z 29 ion:

[HCOOCH3]+  ===>  [CHO]+  +  OCH3

C-O bond scission in the parent molecular ion, mass change 60 - 31 = 29.

Formation of m/z 28.,30 31 ions:

[H3CO]+  ===>  [H2CO]+  +  H

Hydrogen atom loss from the m/z 31 ion.

This could lose hydrogen to give the m/z 28 ion [CO]+.

Formation of m/z 15 ion:

[HCOOCH3]+  ===>  [CH3]+  +  HCO2

From C-O bond scission, mass change 60 - 45 = 15 .


Comparing the infrared, mass, 1H NMR and 13C NMR spectra of the 2 isomers of C2H4O2

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 ethanoic acid (acetic acid) and methyl methanoate (methyl formate) image sizes.

INFRARED SPECTRA: Apart from the significant differences in the fingerprint region at wavenumbers 1500 to 400 cm-1, the most striking difference is the broad O-H stretching band ~3200 cm-1, found in the infrared spectrum of carboxylic acids, but absent in the infrared spectrum of esters.

MASS SPECTRA: Apart from the m/z of 60 for the parent molecular ion and m/z 15 ion [CH3]+, both ethanoic acid and methyl methanoate show few similarities in their mass spectra. Their base ion peaks are quite different - for ethanoic acid it is m/z 43 and for methyl methanoate it is m/z 31. The mass spectrum of methyl methanoate has very prominent peaks for m/z ions 31 and 32 and a complete absence of m/z ions 42, 43 and 45.

1H NMR SPECTRA: The 1H NMR spectra of ethanoic acid and methyl methanoate are similar with two 'wide-apart' chemical shift singlet peaks in the integrated proton ratio of 3:1 (meaning 2 different 1H chemical environments).

13C NMR SPECTRA: The 13C NMR spectra of ethanoic acid and methyl methanoate are similar, both molecules give two C-13 NMR spectral lines (meaning 2 different 13C chemical environments).


Key words & phrases: methyl formate image diagram on how to interpret and explain the mass spectrum of methyl methanoate m/z m/e base peaks, image and diagram of the mass spectrum of methyl methanoate, details of the mass spectroscopy of methyl methanoate,  low and high resolution mass spectrum of methyl methanoate, prominent m/z peaks in the mass spectrum of methyl methanoate, comparative mass spectra of methyl methanoate, the molecular ion peak in the mass spectrum of methyl methanoate, analysing and understanding the fragmentation pattern of the mass spectrum of methyl methanoate, characteristic pattern of peaks in the mass spectrum of methyl methanoate, relative abundance of mass ion peaks in the mass spectrum of methyl methanoate, revising the mass spectrum of methyl methanoate, revision of mass spectroscopy of methyl methanoate, most abundant ions in the mass spectrum of methyl methanoate, how to construct the mass spectrum diagram for abundance of fragmentation ions in the mass spectrum of methyl methanoate, how to analyse the mass spectrum of methyl methanoate, how to describe explain the formation of fragmented ions in the mass spectra of methyl methanoate equations for explaining the formation of the positive ions in the fragmentation of the ionised molecule of methyl methanoate recognising the base ion peak of methyl methanoate interpreting interpretation the mass spectrum of methyl methanoate methyl formate

Stick diagram of the relative abundance of ionised fragments in the fingerprint pattern of the mass spectrum of methyl methanoate. Table of the m/e m/z values and formula of the ionised fragments in the mass spectrum of methyl methanoate. The m/e m/z value of the molecular ion peak in the mass spectrum of methyl methanoate.  The m/e m/z value of the base ion peak in the mass spectrum of methyl methanoate. Possible examples of equations showing the formation of the ionised fragments in methyl methanoate. Revision notes on the mass spectrum of methyl methanoate. Matching and deducing the structure of the methyl methanoate molecule from its mass spectrum. Mass spectroscopy of esters, mass spectra of methyl methanoate, an isomer of molecular formula C2H4O2


Links associated with methyl methanoate

The chemistry of CARBOXYLIC ACIDS and DERIVATIVES revision notes INDEX

Mass spectroscopy index

ALL SPECTROSCOPY INDEXES

All Advanced Organic Chemistry Notes

Use My Google search site box

Email doc b: chem55555@hotmail.com

TOP OF PAGE

 Doc Brown's Chemistry 

*

jobs and opportunities for teenagers best high street shop or best online deals currys pc consumer products computer deals world argos amazon internet deals for students john lewis hobbies and leisure products for teen years dell acer samsung raycon best selling footwear fashion bargains for teenagers bose sony asus huawei HP microsoft in-ear headphones earbuds downloadable games ipad desktop computer laptop computer for school college university students educational college university course opportunities for teenagers latest video games consoles apple iphone online download video games for teenagers google high end mobile phones cell phone bargain health products and advice for teenagers smartphone xiaomi computer laptops desktop pc deals for students oppo high tech products jewellery for teenage girls latest fashion in trainers personal care and beauty products for teenagers latest fashion in shoes best selling fashion clothes clothing bargains for teenagers latest fashion in mobile phones cell phones Nintendo games consoles internet music film entertainment deals subscriptions advice on teenage health conditions

TOP OF PAGE