24154-19-6Relevant academic research and scientific papers
Chemical ionization using CF3+: Efficient detection of small alkanes and fluorocarbons
Dehon, Christophe,Lemaire, Jo?l,Heninger, Michel,Chaput, Aurélie,Mestdagh, Hélène
experimental part, p. 113 - 119 (2011/08/21)
The trifluoromethyl ion CF3+ is evaluated as a chemical ionization (CI) precursor in a compact Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometer. It reacts with alkanes by hydride abstraction allowing characterization and quantification of alkanes up to C4 and cyclic. With larger alkanes fragmentation occurs. Fluorocarbons react by fluoride abstraction. Rate coefficients have been measured for reaction with alkanes, fluoroalkanes, chlorofluoroalkanes as well as several common VOCs. Use of CF3+ for trace analysis in air has been tested on an air sample containing traces of acetone, toluene, benzene and cyclohexane. The results are consistent with those obtained with H3O+ precursor and allow additional cyclohexane quantification.
Mass-Spectrometric Study on Ion-Molecule Reactions of CF3+ with Monosubstituted Benzenes Carrying a Carbonyl Group at Near-Thermal Energies
Tsuji, Masaharu,Aizawa, Masato,Nishimura, Yukio
, p. 1055 - 1063 (2007/10/03)
The gas-phase ion-molecule reactions of CF3+ with five monosubstituted benzenes carrying a carbonyl group (PhCOX: X=H, CH3, C2H5, OCH3, OC2H5) have been studied at near-thermal energies using an ion-beam apparatus. The major product channel for PhCHO, PhCOCH3, and PhCOOCH3 is electrophilic addition to the O-atom leading to initial adduct ions, which are 80.3 - 95.0% of the total product ions. Although no initial adduct ions are observed for PhCOC2H5 and PhCOOC2H5, major product ions are formed by electrophilic addition to the O-atom followed by dissociation and molecular eliminations. The reaction mechanism is discussed based on product ion distributions and semi-empirical calculations of the energies of intermediates and products. The results obtained are compared with reported-ion-cyclotron-resonance data for aliphatic carbonyl compounds.
Mass-Spectrometric Study on Ion-Molecule Reactions of CF3+ with PhX at Near-Thermal Energy
Tsuji, Masaharu,Aizawa, Masato,Nishimura, Yukio
, p. 3497 - 3506 (2007/10/03)
The gas-phase ion-molecule reactions of CF3+ with benzene, toluene, ethylbenzene, styrene, and ethynylbenzene have been studied at near-thermal energy using an ion-beam apparatus.The major product channels are electrophilic addition followed by HF elimination for benzene (93.4+/-2.2percent), toluene (84.3+/-2.4percent) and ethynylbenzene (76.9+/-0.9percent).The dominant product channels for ethylbenzene are electrophilic addition followed by C2H4 and C2H4+HF eliminations (78.9+/-4.7percent), while those for styrene are electrophilic addition followed by one or two HF eliminations and C2H2F2 elimination (91.7+/-0.4percent).Only ethynylbenzene gives an initial adduct ion with a small branching ratio of 6.2+/-0.4percent.As minor product channels, hydride transfer occurs for benzene (6.6+/-2.2percent) and toluene (7.8+/-1.5percent), and charge transfer takes place for toluene (7.9+/-2.0percent), styrene (8.3+/-1.4percent), and ethynylbenzene (6.2+/-0.4percent).The reaction mechanisms are discussed on the basis of product ion distributions and semi-empirical calculations of potential energies of reaction pathways.
13C AND 19F NMR SPECTROSCOPIC STUDY OF SUBSTITUENT EFFECTS IN α,α-DIFLUOROARYLCARBENIUM IONS
Prakash, G. K. Surya,Heiliger, Ludger,Olah, George A.
, p. 33 - 41 (2007/10/02)
In a series of α,α-diarylcarbenium ions 1, one bond 13C-19F coupling constants and the 19F chemical shifts at the cationic center have been used as criteria to follow the extent of fluorine non-bonded electron pair back donation.The electron demand at the cationic center was systematically altered by changing the nature of the substituents on the aryl ring and substituent effects were studied by 13C and 19F NMR spectroscopy.
