The mass spectrometric behaviour of 1,2-epoxy-1-phenyl-2-ethoxy-3,3,3-trifluoropropane (1), 1,2-epoxy-1-phenyl-2-ethoxy-3,3-difluoro-3-chloropropane (2) and 2,3-epoxy-1-cyclohexyl-3-ethoxy-4,4,4-trifluorobutane (3) has been studied by means of electron impact and fast atom bombardment experiments, The decomposition pathways of odd electron molecular ions and protonated molecules have been studied by means of metastable ion spectra, Specific fragmentation channels are present for the three compounds; while for all the compounds C2H5O. loss is highly favoured for 2 the ethyl radical loss becomes predominant, This has been justified by formation of a chloronium cation, Compound 3 only exhibits a product ion related to cleavage of the oxirane ring, suggesting that the lack of conjugation leads to labilisation of the oxirane ring, The protonated molecules partially decompose according to the structure of the alkoxycarbenium ion already proposed in the condensed phase, In the case of 1 the hydroxyl localisation on C(2) has also been evidenced.
The mass spectrometric behaviour of some halogen-containing epoxyethers
FAVRETTO, DONATA;
1997
Abstract
The mass spectrometric behaviour of 1,2-epoxy-1-phenyl-2-ethoxy-3,3,3-trifluoropropane (1), 1,2-epoxy-1-phenyl-2-ethoxy-3,3-difluoro-3-chloropropane (2) and 2,3-epoxy-1-cyclohexyl-3-ethoxy-4,4,4-trifluorobutane (3) has been studied by means of electron impact and fast atom bombardment experiments, The decomposition pathways of odd electron molecular ions and protonated molecules have been studied by means of metastable ion spectra, Specific fragmentation channels are present for the three compounds; while for all the compounds C2H5O. loss is highly favoured for 2 the ethyl radical loss becomes predominant, This has been justified by formation of a chloronium cation, Compound 3 only exhibits a product ion related to cleavage of the oxirane ring, suggesting that the lack of conjugation leads to labilisation of the oxirane ring, The protonated molecules partially decompose according to the structure of the alkoxycarbenium ion already proposed in the condensed phase, In the case of 1 the hydroxyl localisation on C(2) has also been evidenced.
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