[Robin97]

I have to explain the fragmentation patterns of Hexanoic Acid, but i fail to do so.
, i found this Mass Spectrum of Hexanoic Acid online.
I know the peak at m/z=60 is due to a McLafferty fragmentation, but i can't really explain the peaks of m/z=87 and m/z=73.
Could someone please explain this to me?

[Babcock_Hall]

A good place to start is to determine how much mass M^+• lost to make the those two fragments.

[Robin97]

Well according to the loss of the mass I would suggest a ethyl group is lost first (116-29=87) en then a methylene group is lost (87-14=73).
The problem is i can't really understand why that would happen, and what the mechanism is.
I always thought α-cleavages were more important if there is a carbonyl group present.

[Babcock_Hall]

I was a little surprised also, but I consulted Silverstein et al, 4th ed., and they briefly discuss hexanoic acid on page 27.