Kinetic and product studies of the thermal decomposition of dimethylsilane in a single-pulse shock tube and in a stirred flow reactor

Rickborn, S. F.; Rogers, David; Ring, M. A.; O’Neal, H. E.

doi:10.1021/j100275a011

Cited by 23 publications

(14 citation statements)

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“…As mentioned previously, just a few studies have been devoted to the kinetics of the thermal decomposition of cyclopentane [25,27]. Tsang E a = E D + E SE (13) where E D represents the activation energy involved in the disproportionation of two alkyl free radicals and E SE represents the strain energy of the cyclic transition state. The latter was taken to be 6.3…”

Section: Cyclopentanementioning

confidence: 99%

Detailed Kinetic Study of the Ring Opening of Cycloalkanes by CBS-QB3 Calculations

et al. 2006

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This work reports a theoretical study of the gas phase unimolecular decomposition of cyclobutane, cyclopentane and cyclohexane by means of quantum chemical calculations. A biradical mechanism has been envisaged for each cycloalkane, and the main routes for the decomposition of the biradicals formed have been investigated at the CBS-QB3 level of theory. Thermochemical data (∆H°f, S°, C°p) for all the involved species have been obtained by means of isodesmic reactions. The contribution of hindered rotors has also been included. Activation barriers of each reaction have been analyzed to assess the 1 energetically most favorable pathways for the decomposition of biradicals. Rate constants have been derived for all elementary reactions using transition state theory at 1 atm and temperatures ranging from 600 to 2000 K. Global rate constant for the decomposition of the cyclic alkanes in molecular products have been calculated. Comparison between calculated and experimental results allowed to validate the theoretical approach. An important result is that the rotational barriers between the conformers, which are usually neglected, are of importance in decomposition rate of the largest biradicals. Ring strain energies (RSE) in transition states for ring opening have been estimated and show that the main part of RSE contained in the cyclic reactants is removed upon the activation process.

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Section: Cyclopentanementioning

confidence: 99%

Detailed Kinetic Study of the Ring Opening of Cycloalkanes by CBS-QB3 Calculations

et al. 2006

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“…Several studies have been reported on the pyrolysis of dimethylsilane (DMS) under different conditions, such as static flow, 1 stirred flow and shock tube, 2,3 and high-pressure thermal decomposition. 4 Although the products varied, one discovery in common is that both a free-radical process and a molecular elimination mechanism are operative in the pyrolysis of DMS.…”

Section: Introductionmentioning

confidence: 99%

Unraveling the complex chemistry using dimethylsilane as a precursor gas in hot wire chemical vapor deposition

Toukabri

Shi

2014

Phys. Chem. Chem. Phys.

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The gas-phase reaction chemistry when using dimethylsilane (DMS) as a source gas in a hot-wire chemical vapor deposition (CVD) process has been studied in this work. The complex chemistry is unraveled by using a soft 10.5 eV single photon ionization technique coupled with time-of-flight mass spectrometry in combination with the isotope labelling and chemical trapping methods. It has been demonstrated that both free-radical reactions and those involving silylene/silene intermediates are important. The reaction chemistry is characterized by the formation of 1,1,2,2-tetramethyldisilane (TMDS) from dimethylsilylene insertion into the Si-H bond of DMS, trimethylsilane (TriMS) from free-radical recombination, and 1,3-dimethyl-1,3-disilacyclobutane (DMDSCB) from the self dimerization of either dimethylsilylene or 1-methylsilene. At low filament temperatures and short reaction time, silylene chemistry dominates. The free-radical reactions become more important with increasing temperature and time. The same three products have been detected when using tantalum and tungsten filaments, indicating that changing the filament material from Ta to W does not affect much the gas-phase reaction chemistry when using DMS as a source gas in a hot-wire CVD reactor.

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“…Although the formation of CH 4 via molecular elimination has never been reported in the pyrolysis of TriMS, it has been observed when using monomethylsilane 31,32 and dimethylsilane 33,34 in pyrolysis. The results from the pyrolysis of monomethylsilane showed that, out of the three elimination channels, i.e., 1,1-H 2 , 1,2-H 2 , and CH 4 elimination, the dissociation yield to eliminate CH 4 only accounted for 6%.…”

Section: A Formation Of Methane and Other Small Hydrocarbon Moleculesmentioning

confidence: 99%

Effect of trimethylsilane pressure on hot-wire chemical vapor deposition chemistry using vacuum ultraviolet laser ionization mass spectrometry

Toukabri

Shi

2013

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Detecting free radicals during the hot wire chemical vapor deposition of amorphous silicon carbide films using single-source precursors J. Vac. Sci. Technol. A 24, 542 (2006); 10.1116/1.2194023 Vacuum ultraviolet mass-analyzed threshold ionization spectroscopy of hexafluorobenzene: The Jahn-Teller effect and vibrational analysisIn this study, the authors investigated the effect of sample pressure on the reaction chemistry of trimethylsilane (TriMS) in the hot-wire chemical vapor deposition (CVD) process. The secondary gasphase reaction products were examined in a reactor with varying TriMS pressures. The reaction products were analyzed using a laser ionization source with a vacuum ultraviolet wavelength of 118 nm, coupled with mass spectrometry. By increasing TriMS pressure, methane formation was observed. To our knowledge, this is the first successful use of either open-chain alkylsilanes or four-membered-ring (di)silacyclobutane molecules as an independent precursor gas in the hot-wire CVD reactor to achieve methane formation. Our results showed that methane was formed mainly from the radical chain reactions with minor contributions from molecular elimination. The increase in the sample pressure also led to the formation of other small hydrocarbon molecules including acetylene, ethene, propyne, and propene. The formation of hydrogen molecules was enhanced when the sample pressure was increased. In addition, the change in the sample pressure had a direct effect on the radical recombination and disproportionation reactions. This is reflected in the different behavior assumed by the main products from these two types of reactions, i.e., tetramethylsilane, hexamethyldisilane from the former, and three methyl-substituted disilacyclobutanes from the latter. The trapping of free radicals resulting from the in-situ produced ethene and propene molecules is responsible for the observed difference.

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Kinetic and product studies of the thermal decomposition of dimethylsilane in a single-pulse shock tube and in a stirred flow reactor

Cited by 23 publications

References 0 publications

Detailed Kinetic Study of the Ring Opening of Cycloalkanes by CBS-QB3 Calculations

Detailed Kinetic Study of the Ring Opening of Cycloalkanes by CBS-QB3 Calculations

Unraveling the complex chemistry using dimethylsilane as a precursor gas in hot wire chemical vapor deposition

Effect of trimethylsilane pressure on hot-wire chemical vapor deposition chemistry using vacuum ultraviolet laser ionization mass spectrometry

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