Click on any numbered peak for help in interpreting this spectrum.























The peak occurs at m/e = 43 and is the base peak.  The molecular weight, m/e = 43, is a common fragment seen in when an acetyl group is present (CH3CO.+).
























The peak occurs at m/e = 57.  It represents loss of m/e = 43 from the molecular ion, but is not a common fragment.
























The peak occurs at m/e = 100, which is the molecular weight of the compound, making this the molecular ion (m.+).

























C5H8O2  MW = 100.12 

From the molecular formula, the compound has "2 degrees of unsaturation" (two double bonds, carbonyls or rings).




























The spectrum shows a small molecular ion peak, and a pair of peaks at m/e = 57 and 58.  The peak at m/e = 57 corresponds to loss of m/e = 43, which is the base peak and corresponds to the acylium ion (CH3CO+).  The m/e = 57 fragment corresponds to C3H5O, suggesting the original compound was an ester with this molecular formula.























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Structure:  structure

IUPAC Name:  2-propenyl ethanoate (allyl acetate)

MS Fragments:
fragments

The spectrum shows a small molecular ion peak, and a peak at m/e = 57.  The peak at m/e = 57 corresponds to loss of m/e = 43, which is the base peak and corresponds to the acylium ion (CH3CO+).  The m/e = 57 fragment corresponds to C3H5O, suggesting the original compound was an allyl (-O-CH2CH=CH) or methylvinyl (-O-CH=CHCH3) ester.  Either of these would generate the peak observed at m/e = 41.  Proton or 13 C NMR would readily distinguish between the two possible structures.