No abstract

The fragmentation of the molecular ions of methyl octadecanoates into methoxycarbonylalkyl ions with m/e 143 and 199 has been investigated. The contributions of three reaction types are determined with esters labelled with 13C at the 8 and 14 positions. The required methyl 8-and 14-13C-octadecanoates have been synthesized by coupling a methoxycarbonylalkanoyl chloride with thiophene, followed by Wolf-Kishner reduction, esterification, introduction of the isotopic carbon atom by acylation, again reduction and desulfurization. IntroductionThe mass spectra of many fatty acid methyl esters have been investigated both at low 1-3 and high resolutions 4 . The fragmentation reactions were investigated for several simple esters by measuring appearance potentials5-8 by means of esters labelled with 13C (Ref. and by investigation of the metastable peaks ll.

No abstract

A number of metastable peaks in the mass spectra of methyl acetate, propionate, butyrate, valerate and hexanoate were investigated. By measuring the kinetic energy of the ions of those peaks 28 degradation reactions of the esters were determined.