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.

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.

Metastable Dissociation of CH5+ Ions in the Methane Mass Spectrum

1969 ◽  
Vol 24 (12) ◽  
pp. 1959-1963
Author(s):  
I Mastan ◽  
V Mercea
Keyword(s):  
Mass Spectrum ◽  
Mass Spectrometer ◽  
Cross Sections ◽  
Mass Spectrometric ◽  
Collision Induced Dissociation ◽  
Spectrometric Method ◽  
Mass Spectrometric Method ◽  
Pass Through ◽  
Straight Lines

AbstractThe main dissociation channels of the CH5+ ion, i. e. have been investigated by a mass spectrometric method. The pressure dependences of the ratios I14,90/I17 and I13,26/I17, in the range from 4,4·10-4 to 1·10-4 Torr, were plotted. The two ratios depend linearly on the pressure in the mass spectrometer analyzer. Since the two straight lines do not pass through the origine the conclusion is drawn that, for both dissociation channels of the CH5+ ion, besides the collision-induced transitions, spontaneous transitions, i. e. pure metastable transitions, take place. The spontaneous dissociations constants (λ1 = 7,5·105 sec-1 , λ2 = 5,2·104 sec-1) and collision-induced dissociation cross-sections (σ1 = 5,25 · 10-16 cm2 , σ2 = 3,2·10-16 cm2) have been estimated. These results are discussed and compared with those reported by other authors.

Mass Spectrometric Identification of 2-Mercaptobenzothiazole Sulfenamide Accelerators in Rubber Vulcanizates

1973 ◽  
Vol 46 (4) ◽  
pp. 1035-1043 ◽  
Author(s):  
A. S. Hilton ◽  
A. G. Altenau
Keyword(s):  
Mass Spectrum ◽  
Solvent Extraction ◽  
Sample Preparation ◽  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Mass Spectrometric Method ◽  
Sample Tube ◽  
Fragment Ions ◽  
Amine Fragment ◽  
Mass Spectrometric Identification

Abstract The identification of accelerators in rubber vulcanizates has traditionally been a difficult and tedious task. The mass spectrometric method described in this paper offers a simple and expedient approach to the identification of 2-mercaptobenzothiazole sulfenamides. Neither complicated sample preparation nor solvent extraction of the vulcanizates is required as in the more common methods employed. Only about one-half gram of vulcanizate is needed for the analysis. The sample tube is attached to the mass spectrometer, heated for 15–20 min at 150–200° C and then the mass spectrum of the volatiles is recorded. The characteristic amine fragment ions are utilized for identification of the amine portion while the presence of benzothiazole is indicated by a peak at m/e=135. Spectra obtained from analysis of seven vulcanizates containing different accelerators are presented and the results discussed. The identification of the accelerator in a competitor's tread is also discussed.

Tandem Mass Spectrometric Evaluation of Core Structures of Aromatic Compounds after Catalytic Deoxygenation

2017 ◽  
Author(s):  
Xueming Dong
Keyword(s):  
Aromatic Compounds ◽  
Supported Catalyst ◽  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Mass Spectrometric Method ◽  
Aromatic Rings ◽  
Tandem Mass Spectrometric ◽  
Catalytic Deoxygenation ◽  
Oxygen Atoms

Catalytic deoxygenation of coal enhances the stability and combustion performance of coal-derived liquids. However, determination of the selectivity of removal of oxygen atoms incorporated in or residing outside of aromatic rings is challenging. This limits the ability to evaluate the success of catalytic deoxygenation processes. A mass spectrometric method, in-source collision-activated dissociation (ISCAD), combined with high resolution product ion detection, is demonstrated to allow the determination of whether the oxygen atoms in aromatic compounds reside outside of aromatic rings or are part of the aromatic system, because alkyl chains can be removed from aromatic cores via ISCAD. Application of this method for the analysis of a subbituminous coal treated using a supported catalyst revealed that the catalytic treatment reduced the number of oxygen-containing heteroaromatic rings but not the number of oxygen atoms residing outside the aromatic rings.<br>

Tandem Mass Spectrometric Evaluation of Core Structures of Aromatic Compounds after Catalytic Deoxygenation

2017 ◽  
Author(s):  
Xueming Dong
Keyword(s):  
Aromatic Compounds ◽  
Supported Catalyst ◽  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Mass Spectrometric Method ◽  
Aromatic Rings ◽  
Tandem Mass Spectrometric ◽  
Catalytic Deoxygenation ◽  
Oxygen Atoms

Catalytic deoxygenation of coal enhances the stability and combustion performance of coal-derived liquids. However, determination of the selectivity of removal of oxygen atoms incorporated in or residing outside of aromatic rings is challenging. This limits the ability to evaluate the success of catalytic deoxygenation processes. A mass spectrometric method, in-source collision-activated dissociation (ISCAD), combined with high resolution product ion detection, is demonstrated to allow the determination of whether the oxygen atoms in aromatic compounds reside outside of aromatic rings or are part of the aromatic system, because alkyl chains can be removed from aromatic cores via ISCAD. Application of this method for the analysis of a subbituminous coal treated using a supported catalyst revealed that the catalytic treatment reduced the number of oxygen-containing heteroaromatic rings but not the number of oxygen atoms residing outside the aromatic rings.<br>

scholarly journals Mass Spectrometric Calibration Procedure for Real-Time Detection of Lighter Hydrocarbons

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2123
Author(s):  
Makuachukwu F. Mbaegbu ◽  
Puspa L. Adhikari ◽  
Ipsita Gupta ◽  
Mathew Rowe
Keyword(s):  
Real Time ◽  
Mass Spectrometer ◽  
Calibration Procedure ◽  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Mass Selection ◽  
Mass Spectrometric Method ◽  
Mass Spectrometers ◽  
Drilling Rig

Determining gas compositions from live well fluids on a drilling rig is critical for real time formation evaluation. Development and utilization of a reliable mass spectrometric method to accurately characterize these live well fluids are always challenging due to lack of a robust and effectively selective instrument and procedure. The methods currently utilized need better calibration for the characterization of light hydrocarbons (C1–C6) at lower concentrations. The primary goal of this research is to develop and optimize a powerful and reliable analytical method to characterize live well fluid using a quadruple mass spectrometer (MS). The mass spectrometers currently being used in the field have issues with detection, spectra deconvolution, and quantification of analytes at lower concentrations (10–500 ppm), particularly for the lighter (<30 m/z) hydrocarbons. The objectives of the present study are thus to identify the detection issues, develop and optimize a better method, calibrate and QA/QC the MS, and validate the MS method in lab settings. In this study, we used two mass spectrometers to develop a selective and precise method to quantitatively analyze low level lighter analytes (C1–C6 hydrocarbons) with masses <75 m/z at concentrations 10–500 ppm. Our results suggest that proper mass selection like using base peaks with m/z 15, 26, 41, 43, 73, and 87, respectively, for methane, ethane, propane, butane, pentane, and hexane can help detect and accurately quantify hydrocarbons from gas streams. This optimized method in quadrupole mass spectrometer (QMS) will be invaluable for early characterization of the fluid components from a live hydrocarbon well in the field in real time.

scholarly journals Development of a mass spectrometric method to quantitate platelet activating factor in mouse urine.

1989 ◽  
Vol 30 (12) ◽  
pp. 1977-1981
Author(s):  
E Benfenati ◽  
D Macconi ◽  
M Noris ◽  
G Icardi ◽  
L Bettazzoli ◽  
...  
Keyword(s):  
Platelet Activating Factor ◽  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Mass Spectrometric Method ◽  
Mouse Urine

Mass spectrometric method of analysing saturated cyclic sulphides

1969 ◽  
Vol 9 (1) ◽  
pp. 73-82
Author(s):  
Y BRODSKII ◽  
R KHMELNITSKII ◽  
A POLYAKOVA
Keyword(s):  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Mass Spectrometric Method
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