The Fragment Ion C13H9O2 m/z 197 in the Mass Spectra of 2-(2′-R-phenyl)benzoic Acids

1990 ◽  
Vol 43 (1) ◽  
pp. 203 ◽  
Author(s):  
RG Gillis ◽  
QN Porter
Keyword(s):  
Mass Spectrum ◽  
Electron Impact ◽  
Mass Spectra ◽  
Chemical Ionization ◽  
Electron Impact Mass Spectrum ◽  
Benzoic Acids ◽  
Ipso Substitution ◽  
Methane Chemical Ionization ◽  
Electron Impact Mass ◽  
Impact Mass

In the electron impact mass spectrum of 2-(2°-R-phenyl)benzoic acids where R=H, NO2, OCH3, COOH, or Br, an abundant fragment ion m/z 197 is formed by an ipso substitution in which R is expelled as a radical. The structure of the ion m/z 197 has been shown by collision-activated dissociation to be identical with that of the protonated molecule formed by methane chemical ionization of 6H-dibenzo[ b,d ]pyran-6-one.

Oxygen equilibration in the mass spectra of 2-benzoylbenzoic acid

1976 ◽  
Vol 29 (2) ◽  
pp. 301
Author(s):  
MJ Lacey ◽  
JS Shannon
Keyword(s):  
Mass Spectrum ◽  
Benzoic Acid ◽  
Electron Impact ◽  
Mass Spectra ◽  
Chemical Ionization ◽  
Molecular Ions ◽  
Electron Impact Mass Spectrum ◽  
Primary Fragmentation ◽  
Electron Impact Mass ◽  
Impact Mass

Positional integrity of the label is maintained in the molecular ions of 2-ben~oyl[18O]benzoic acid prior to a number of primary fragmentation modes. Positional integrity is also evident for some source and metastable reactions of the protonated molecular ions formed in its chemical ionization (H2) mass spectrum. The (M-Ph)+ ions formed in the electron impact mass spectrum, however, fragment further after complete equilibration of their oxygen atoms.

Spectrométrie de masse du chloro-1 diméthoxy-2,6 naphtalène; comparaison de données théoriques et expérimentales

1983 ◽  
Vol 61 (9) ◽  
pp. 2089-2091 ◽  
Author(s):  
Jean-Claude Richer ◽  
Simone Odiot
Keyword(s):  
Mass Spectrum ◽  
Electron Impact ◽  
Electron Impact Mass Spectrum ◽  
Relative Stabilities ◽  
Spectrométrie De Masse ◽  
Electron Impact Mass ◽  
Impact Mass

In an unambiguous manner we have synthesized 1-chloro-2,6-dimethoxy-d3-naphthalene (5) and examined its electron impact mass spectrum. We report here calculations on the relative stabilities of 1-chloro and 5-chloro-6-methoxy-2-naphthols (4a and 4b) and on the relative stabilities of the O—CH3 bond in the 2 and 6 positions of compound 5. [Journal translation]

Charge exchange mass spectra of some C5H10 isomers

1981 ◽  
Vol 59 (12) ◽  
pp. 1753-1759 ◽  
Author(s):  
Yip Hoi Li ◽  
Jan A. Herman ◽  
Alex. G. Harrison
Keyword(s):  
Electron Impact ◽  
Charge Exchange ◽  
Mass Spectra ◽  
Chemical Ionization ◽  
Relative Energy ◽  
Ionization Mass ◽  
Single Source ◽  
Fragmentation Pathways ◽  
Electron Impact Mass ◽  
Impact Mass

Reagent gas systems are described for use in a single-source chemical ionization mass spectrometer which permit charge exchange mass spectra to be obtained using CS2+•(∼10.2 eV), COS+•(11.2 eV), Xe+•(∼12.5 eV), CO+•(14.0 eV), N2+•(15.3 eV), and Ar+• (15.8 eV) (recombination energies in brackets) as the major reactant ions. Using these reagent gas systems the charge exchange mass spectra of cyclopentane, 1-pentene, 3-methyl-l-butene, 2-methyl-l-butene, 2-pentene, and 2-methyl-2-butene have been obtained. It is shown that these spectra can be used to construct breakdown graphs which adequately depict the relative energy dependences of the fragmentation pathways and rationalize the 70 eV electron impact mass spectra.

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