AN ELECTRON IMPACT STUDY OF SOME C8HI0 ISOMERS

1965 ◽  
Vol 43 (1) ◽  
pp. 211-218 ◽  
Author(s):  
F. Meyer ◽  
P. Haynes ◽  
Stewart McLean ◽  
A. G. Harrison
Keyword(s):  
Mass Spectrum ◽  
Electron Impact ◽  
Mass Spectra ◽  
Major Part ◽  
The Other ◽  
Fragmentation Pattern ◽  
Impact Study ◽  
Deuterium Labelling ◽  
Appearance Potential ◽  
Alkyl Benzenes

The mass spectra of 1-, 2-, and 6-methylspiro[2.4]hepta-1,3-diene have been measured and found to be very similar to the spectra of 7-methylcycloheptatriene and the isomeric alkyl benzenes. It is concluded that in all cases the major part of the fragmentation occurs by identical paths involving identical intermediates. This conclusion is supported by deuterium labelling and appearance potential data. On the other hand the mass spectrum of 2,5-dimethyl-1,5-hexadien-3-yne, an acyclic C8H10 isomer, shows a number of significant differences in its fragmentation pattern. These differences are reflected in the energetics of ion formation and it is concluded that in this case the fragmentation proceeds through different intermediates.

AN ELECTRON IMPACT STUDY OF METHYL PHENYL ETHERS

1964 ◽  
Vol 42 (8) ◽  
pp. 2008-2017 ◽  
Author(s):  
F. Meyer ◽  
A. G. Harrison
Keyword(s):  
Electron Impact ◽  
Methyl Ether ◽  
Mass Spectra ◽  
Impact Study ◽  
Deuterium Labelling ◽  
Appearance Potential ◽  
Phenyl Ethers ◽  
Methyl Phenyl

The mass spectra of anisole, anisole-methoxy-d3, meta and para methylanisole, meta and para methyl-d3-anisole, and meta and para niethylanisole-methoxy-d3 have been recorded. From the deuterium labelling and appearance potential studies, the main fragmentation paths on electron impact have been elucidated. The energetics of formation of the CH3OC7H6+ ion from the methylanisoles, benzyl methyl ether, 7-methoxycycloheptatriene, and the ethylanisoles have been studied.

IONIZATION AND DISSOCIATION OF FORMATE ESTERS BY ELECTRON IMPACT

1963 ◽  
Vol 41 (8) ◽  
pp. 2054-2059 ◽  
Author(s):  
D. Van Raalte ◽  
A. G. Harrison
Keyword(s):  
Formic Acid ◽  
Electron Impact ◽  
Proton Affinity ◽  
Mass Spectra ◽  
Methyl Formate ◽  
Ethyl Formate ◽  
Kcal Mole ◽  
Deuterium Labelling ◽  
Appearance Potential

The mass spectra of methyl formate-d, ethyl formate-d, and isopropyl formate-d are compared with the mass spectra of the undeuterated compounds. By use of the deuterium labelling and appearance potential studies the dissociation reactions leading to a number of the oxygen-containing ions have been elucidated. The proton affinity of formic acid is estimated to be 157 kcal/mole from the appearance potential of the HC(OH)2+ ion in the mass spectra of ethyl formate and isopropyl formate.

AN ELECTRON IMPACT STUDY OF CHLOROMETHYL AND DICHLOROMETHYL DERIVATIVES

1962 ◽  
Vol 40 (9) ◽  
pp. 1730-1737 ◽  
Author(s):  
A. G. Harrison ◽  
T. W. Shannon
Keyword(s):  
Mass Spectrum ◽  
Electron Impact ◽  
Methyl Chloride ◽  
Heat Of Formation ◽  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Mass Spectrometric Method ◽  
Impact Study ◽  
Kcal Mole ◽  
Appearance Potential

The appearance potential of the CH2Cl+ ion has been measured from methyl chloride, dichloromethane, bromochloromethane, and ethyl chloride. The results lead to ΔHf(CH2Cl+) = 230 ± 3 kcal/mole. The heat of formation of CHCl2+ is estimated to be 215 ± 3 kcal/mole from the appearance potential of this ion in the mass spectrum of chloroform and of bromodichloromethane. By the indirect mass spectrometric method ΔHf(CH2Cl) = 29 ± 3 kcal/mole and ΔHf(CHCl2) = 15 ± 3 kcal/mole are obtained. The ionization potentials of a number of chlorine-containing compounds have been measured.

scholarly journals MASS SPECTRA OF SOME FUROQUINOLINE ALKALOIDS

1965 ◽  
Vol 43 (9) ◽  
pp. 2516-2521 ◽  
Author(s):  
D. M. Clugston ◽  
D. B. Maclean
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
The Other ◽  
Methoxyl Group ◽  
Quinoline Ring

The mass spectra of six furoquinoline alkaloids have been recorded and mechanisms have been proposed for their fragmentation upon electron impact. Strong metastable peaks, present in all spectra, have aided in the interpretation of the fragmentation of these alkaloids. The three alkaloids with a methoxyl group in the 8-position of the quinoline ring may be differentiated from the other three by the presence of relatively intense peaks at M-1 and M-29.

scholarly journals Electron Impact Ionization Mass Spectra of 3-Amino 6-Chloro2-methyl Quinazolin-4-(3H)-one Derivative

2021 ◽  
pp. 1-5
Author(s):  
Osarumwense Peter Osarodion ◽  
◽  
Omotade Treasure Ejodamen ◽  
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Impact Ionization ◽  
Cyclic Compound ◽  
Electron Impact Ionization ◽  
Ionization Mass ◽  
Fragmentation Pattern ◽  
Molecular Ion ◽  
Mass Spectral ◽  
Characteristic Fragmentation

Looking at the previous studies on quinazolinones derivatives, only limited information’s are available on their mass spectral along with the preparation of novel quinazolin-4-(3H)-one derivatives The condensation of Methyl-2-amino-4-Chlorobenzoate with acetic anhydride yielded the cyclic compound 2-methyl 7-Chloro-1, 3-benzo-oxazine-4-one (1) which further produce 3-Amino-2-Methyl 7-Chloro quinazolin-4(3H)-ones (2) via the reaction with hydrazine hydrate. The compounds synthesized were unequivocally confirmed by means of Infrared, Nuclear Magnetic Resonance (1H and 13C), Gas Chromatography-Mass spectrophotometry and Elemental analysis. Discussion: The molecular ion of m/z 235 fragments to give m/z 220 by loss of –NH group. The ion of m/z 220 was broken to give m/z 206 by losing CH2 group and fragment to m/z 177 by loss of HCO. This fragmented to m/z 162 by loss of –CH3 group and then m/z 136 by loss of CN group. The loss of O gave m/z 120 which fragment to give m/z 93 by loss of –HCN and finally gave m/z 65 by loss of CO group. Conclusion: The electron impact ionization mass spectra of compound 2show a weak molecular ion peak and a base peak of m/z 235resulting from a cleavage fragmentation. Compound 2 give a characteristic fragmentation pattern. From the study of the mass spectra of compound 2, it was found that the molecular ion had fragmented to the m/z 220. The final fragmentation led to ion of m/z 93 and ion of mass m/z 65, respectively

Mass spectra of new heterocycles: XVI. Electron impact study of alkyl 5-aminothiophene-2-carboxylates

2017 ◽  
Vol 53 (6) ◽  
pp. 913-919 ◽  
Author(s):  
L. V. Klyba ◽  
N. A. Nedolya ◽  
E. R. Sanzheeva ◽  
O. A. Tarasova
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Impact Study

ENERGETICS AND MECHANISM OF HYDRONIUM ION FORMATION BY ELECTRON IMPACT

1963 ◽  
Vol 41 (12) ◽  
pp. 3118-3126 ◽  
Author(s):  
D. Van Raalte ◽  
A. G. Harrison
Keyword(s):  
Water Molecule ◽  
Electron Impact ◽  
Proton Affinity ◽  
Mass Spectra ◽  
Kcal Mole ◽  
Deuterium Labelling ◽  
Ion Formation ◽  
Hydronium Ion

The reactions leading to formation of the hydronium ion in the mass spectra of a number of alcohols and formate esters have been elucidated through a study of appearance potentials and metastable transitions and by the use of deuterium labelling. The results lead to ΔHf(H3O+) = 157 ± 3 kcal/mole corresponding to a proton affinity of the gaseous water molecule of 151 ± 3 kcal/mole.

The isolation of 11-oxotetrahydrorhombifoline from Ormosia coutinhoi and a study of its mass spectrum

1967 ◽  
Vol 45 (7) ◽  
pp. 751-757 ◽  
Author(s):  
Stewart McLean ◽  
A. G. Harrison ◽  
D. G. Murray
Keyword(s):  
Mass Spectrum ◽  
Electron Impact ◽  
Mass Spectra ◽  
Equilibrium Theory ◽  
Side Chain ◽  
Fragmentation Reaction ◽  
Quasi Equilibrium ◽  
Molecular Ion ◽  
Dihydro Derivative ◽  
A Minor

11-Oxotetrahydrorhombifoline (I) has been isolated from the alkaloidal extract of the bark of Ormosia coutinhoi, and its dihydro derivative II has been prepared. An examination of the mass spectra of these compounds and of their 3,3-d2 derivatives has led to the elucidation of the course of the major electron impact induced fragmentations undergone by the molecules. The main fragmentation of I leads to loss of C3H5 from the side chain to form an ion of m/e 221, with a minor path involving a central fission of the molecular ion to form an ion of m/e 150. The mass spectrum of II shows that the loss of C3H7 to form the ion of m/e 221 is a minor process, the main fragmentation reaction involving a central fission to form an ion of m/e 152 analogous to the ion of m/e 150 from I. This change in the spectrum is shown to be consistent with predictions based on the quasi-equilibrium theory of mass spectra.

Synthesis and mass spectra of piperidine and piperazine N-oxyl radicals

1987 ◽  
Vol 52 (9) ◽  
pp. 2266-2273 ◽  
Author(s):  
Viera Kaliská ◽  
Štefan Toma ◽  
Ján Leško
Keyword(s):  
Liquid Crystals ◽  
Electron Impact ◽  
Mass Spectra ◽  
Fragmentation Pattern ◽  
Spin Probes ◽  
Electron Impact Mass ◽  
Impact Mass

It has been found that ultrasound could accelerate the synthesis of piperidine and piperazine N-oxyl radicals. These radicals were investigated for their utilization as spin probes for checking the properties of liquid crystals. Electron impact mass spectra of the N-oxyl radicals were recorded and their fundamental fragmentation pattern was proposed.

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