Shock-tube study of the decomposition of octamethylcyclotetrasiloxane and hexamethylcyclotrisiloxane

2020 ◽  
Vol 234 (7-9) ◽  
pp. 1395-1426 ◽  
Author(s):  
Paul Sela ◽  
Sebastian Peukert ◽  
Jürgen Herzler ◽  
Christof Schulz ◽  
Mustapha Fikri
Keyword(s):  
Mass Spectrometry ◽  
Shock Tube ◽  
High Repetition Rate ◽  
Rate Coefficients ◽  
Gas Chromatography Mass Spectrometry ◽  
High Concentration ◽  
Gas Phase Chemistry ◽  
Reflected Shock ◽  
Flight Mass Spectrometry ◽  
Phase Chemistry

AbstractShock-tube experiments have been performed to investigate the thermal decomposition of octamethylcyclotetrasiloxane (D4, Si4O4C8H24) and hexamethylcyclotrisiloxane (D3, Si3O3C6H18) behind reflected shock waves by gas chromatography/mass spectrometry (GC/MS) and high-repetition-rate time-of-flight mass spectrometry (HRR-TOF-MS) in a temperature range of 1160–1600 K and a pressure range of 1.3–2.6 bar. The main observed stable products were methane (CH4), ethylene (C2H4), ethane (C2H6), acetylene (C2H2) and in the case of D4 pyrolysis, also D3 was measured as a product in high concentration. A kinetics sub-mechanism accounting for the D4 and D3 gas-phase chemistry was devised, which consists of 19 reactions and 15 Si-containing species. The D4/D3 submechanism was combined with the AramcoMech 2.0 (Li et al., Proc. Combust. Inst. 2017, 36, 403–411) to describe hydrocarbon chemistry. The unimolecular rate coefficients for D4 and D3 decomposition are represented by the Arrhenius expressions ktotal/D4(T) = 2.87 × 1013 exp(−273.2 kJ mol−1/RT) s−1 and ktotal/D3(T) = 9.19 × 1014 exp(−332.0 kJ mol−1/RT) s−1, respectively.

Shock-tube study of the decomposition of tetramethylsilane using gas chromatography and high-repetition-rate time-of-flight mass spectrometry

2018 ◽  
Vol 20 (16) ◽  
pp. 10686-10696 ◽  
Author(s):  
P. Sela ◽  
S. Peukert ◽  
J. Herzler ◽  
M. Fikri ◽  
C. Schulz
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Shock Tube ◽  
Repetition Rate ◽  
High Repetition Rate ◽  
High Repetition ◽  
Reflected Shock ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Tube Study

The decomposition of tetramethylsilane was studied in shock-tube experiments in a temperature range of 1270–1580 K and pressures ranging from 1.5 to 2.3 bar behind reflected shock waves combining GC/MS and HRR-TOF-MS.

Shock Tube Studies of the Reactions of Hydrogen Atoms. I. The Reaction H + NH3 → H2 + NH2

1974 ◽  
Vol 52 (7) ◽  
pp. 1171-1180 ◽  
Author(s):  
John E. Dove ◽  
Wing S. Nip
Keyword(s):  
Shock Tube ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
High Concentration ◽  
Hydrogen Atoms ◽  
Elementary Reactions ◽  
Temperature Range ◽  
Reflected Shock ◽  
Branched Chain ◽  
Chain Explosion

The partial equilibrium state following the branched-chain explosion of shock-heated rich H2/O2/diluent mixtures contains a high concentration of H atoms. The conditions under which this state can be used as a source of H atoms for the study of elementary reactions have been investigated. A small amount of NH3 was added to H2/O2/inert gas mixtures in order to measure the rate of the reaction H + NH3 → H2 + NH2. The pseudo-first order decay of NH3 in an approximately ten-fold excess of H atoms was followed by a time-of-flight mass spectrometer which sampled from the reflected shock region in a shock tube. The rate coefficient for this reaction, determined over the temperature range 1500–2150 °K, is 1013.44±0.10 exp −(17 400 ± 1 300 cal mol−1)/RT cm3 mol−1 s−1.It is pointed out that, under certain stated conditions, the method can also be extended to study the rates of elementary reactions involving O atoms and OH radicals. From our experiments, upper limits on the rate coefficients of the reactions OH + NH3 → H2O + NH2 and O + NH3 → OH + NH2 over the temperature range 1620–1920 °K are 8 × 109T0.08 exp (−1100/RT) and 1 × 1013 exp (−6600/RT), respectively.

Mass Spectrometry and Gas-Phase Chemistry of Anilines

ChemInform ◽  
2007 ◽  
Vol 38 (30) ◽  
Author(s):  
Marcos N. Eberlin ◽  
Daniella Vasconcellos Augusti ◽  
Rodinei Augusti
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Gas Phase Chemistry ◽  
Phase Chemistry

Rate coefficients for interstellar gas-phase chemistry

1993 ◽  
Vol 89 (13) ◽  
pp. 2193 ◽  
Author(s):  
Bertrand R. Rowe ◽  
Andr� Canosa ◽  
Ian R. Sims
Keyword(s):  
Gas Phase ◽  
Rate Coefficients ◽  
Interstellar Gas ◽  
Gas Phase Chemistry ◽  
Phase Chemistry

scholarly journals Identification of the designer benzodiazepine 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine (flualprazolam) in an anesthesia robbery case

2019 ◽  
Vol 38 (1) ◽  
pp. 269-276 ◽  
Author(s):  
Zhenhua Qian ◽  
Cuimei Liu ◽  
Jian Huang ◽  
Qingqing Deng ◽  
Zhendong Hua
Keyword(s):  
Mass Spectrometry ◽  
Analytical Data ◽  
Drug Market ◽  
Gas Chromatography Mass Spectrometry ◽  
Designer Drug ◽  
New Psychoactive Substances ◽  
Psychoactive Substances ◽  
Flight Mass Spectrometry ◽  
Emerging Compounds ◽  
Analytical Properties

Abstract Purpose This publication reports analytical properties of the designer benzodiazepine 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine (flualprazolam) seized in an anesthesia robbery case. Methods The target compound was identified by liquid chromatography–quadrupole time-of-flight-mass spectrometry (LC–QTOF-MS), gas chromatography–mass spectrometry (GC–MS), and nuclear magnetic resonance (NMR) spectroscopy. Results We could obtain detailed analytical data of flualprazolam—a new designer benzodiazepine available on the designer drug market. Conclusions More designer benzodiazepines have been detected and seized on the illegal drug scene as new psychoactive substances during the last 5 years. In this study, we presented analytical data of flualprazolam to assist forensic laboratories that encounter these newly emerging compounds in casework. This is the first report on this compound in illegal products.

scholarly journals A modular, multi-diagnostic, automated shock tube for gas-phase chemistry

2019 ◽  
Vol 90 (6) ◽  
pp. 064104 ◽  
Author(s):  
Mark E. Fuller ◽  
Mal Skowron ◽  
Robert S. Tranter ◽  
C. Franklin Goldsmith
Keyword(s):  
Shock Tube ◽  
Gas Phase ◽  
Gas Phase Chemistry ◽  
Phase Chemistry
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