19270-10-1Relevant articles and documents
Thermal dissociation of acetophenone molecular ions activated by infrared radiation
Sena, Marcelo,Riveros, Jose M.
, p. 4384 - 4391 (1997)
The thermal dissociation of the molecular ions of acetophenone (C6H5COCH3?+ → C6H5CO+ + ?CH3) and acetophenone-d3 (C6H5COCD3?+ → C6H5CO+ + ?CD3) induced by broad band infrared radiation has been studied in the cell of an FT-ICR spectrometer. Rate constants in the range of 0.5-10 s-1 have been obtained for the system of ions exposed to a radiation source equivalent to blackbody temperatures between 1100 and 1600 K. The unimolecular dissociation is almost pressure independent in the 4 × 10-8 to 5 × 10-7 Torr range indicating that the most important mechanism is of a noncollisional nature. Activation energies obtained from Arrhenius-type plots yield 46.6 ± 2.0 kJ mol-1 for acetophenone and 44.9 ± 2.2 kJ mol-1 for acetophenone-d3. The dissociation process has been modeled by a Monte Carlo simulation and by numerical solution of the master equation of a process which takes into account interaction with the background radiation field through absorption and emission. These calculations reveal that meaningful activation energies can be obtained from these experiments even though the exact radiance viewed by the ions is not known. Solution of the master equation reveals that the experimental activation energies are consistent with a dissociation energy of 80.5 kJ mol-1 for the acetophenone molecular ion. This result is used to derive a heat of formation of 745 kJ mor-1 for the C6H5CO+ ion.
Synthesis of oxazoles by silver catalysed oxidative decarboxylation-cyclization of α-oxocarboxylates and isocyanides
Ma, Yiyang,Yan, Zhiyuan,Bian, Changliang,Li, Ke,Zhang, Xiaowen,Wang, Mengfan,Gao, Xinlong,Zhang, Heng,Lei, Aiwen
supporting information, p. 10524 - 10527 (2015/06/25)
A silver catalysed synthesis of oxazoles by the oxidative decarboxylation-cyclization of α-oxocarboxylates and isocyanides was developed. This method provided a novel strategy to construct oxazole rings compared to traditional methods. Mechanistic investigations such as operando IR, EPR and radical inhibition experiments were carefully done and confirmed the acyl cation and Ag(ii) as the intermediates in this transformation, and the involvement of a radical decarboxylative process.
Determination of the Enthalpies of Formation of C6H5CH2O·, p-CH3OC6H4CH2O·, and C6H5CHOH Radicals by Photoionization Mass Spectrometry
Ponomarev,Takhistov,Orlov
, p. 1774 - 1776 (2007/10/03)
The enthalpies of formation (kJ mol-1) of PhCH2O· (125), p-CH3OC6H4CH2O· (-37), and PhCHOH radicals (28) were determined from the energies of appearance of the corresponding fragment ions. The reliability of these data is confirmed by the coincidence of the experimental results with those calculated by the method of isodesmic reactions.
