Decomposition reaction rate of BCl3-CH4-H2 in the gas phase
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| 024 | 7 | 0 | |a 10.1007/s00214-015-1698-3 |2 doi |
| 035 | |a (NATIONALLICENCE)springer-10.1007/s00214-015-1698-3 | ||
| 245 | 0 | 0 | |a Decomposition reaction rate of BCl3-CH4-H2 in the gas phase |h [Elektronische Daten] |c [Yan Liu, Kehe Su, Qingfeng Zeng, Laifei Cheng, Litong Zhang] |
| 520 | 3 | |a The decomposition reaction rate of the BCl3+CH4+H2 gas-phase reaction system in preparing boron carbide or boron was investigated based on the most favorable reaction pathways proposed in Liu et al. (Struct Chem 23:1677, 2012). The rate constants of all the elementary reactions were evaluated with the variational transition-state theory in which the necessary vibrational frequencies for the stationary points as well as the selected points along the minimum energy paths (MEPs) were calculated with density functional theory B3PW91/6-311G(d,p) and the energies were refined with the accurate model chemistry method G3(MP2). For the elementary reaction associated with a transition state, the MEP was obtained with the intrinsic reaction coordinates, while for that without a transition state, the relaxed potential energy surface scan was employed to obtain the MEP. The rate constants were calculated for temperatures within 200-2000K and fitted into three-parameter Arrhenius expressions. The reaction rate was investigated by using the COMSOL software to solve numerically the coupled differential rate equations. The results show that reactants are consumed with a fast process and the consumption rate increases with increasing temperature. The concentration, consistent with the thermodynamics computations, of the reactants achieves a constant of consuming completely with the extension of time. The concentrations of precuts BC and C also increase with increasing temperature, and the concentration of B is always larger than BC in the temperature range of 1200-1600K. Thus, the rich boron product is easy to form and to deposit at higher temperatures. However, the difference in concentrations (logarithm values) between BC and B becomes smaller with the increasing temperature. This result is also consistent with the experimental conclusion of Ye et al. (Mater Rev 24:108, 2010). The logarithm of the decreasing rate for CH4 and the reciprocal temperature have excellent linear relationship at 700-2000K with a correlation coefficient of 0.9999. The slope of the line corresponds to an apparent activation energy 208.4kJmol−1, which is comparable with the energy barrier (238.6kJmol−1) of the rate control reaction. The logarithm of the decreasing rate for BCl3 and the reciprocal temperature also have an excellent linear relationship in two temperature ranges 700-1600 and 1700-2000K, predicting that the reaction follows obviously two different kinetics mechanisms. The correspondence apparent activation energies are 201.7 and 378.3kJmol−1, respectively. | |
| 540 | |a Springer-Verlag Berlin Heidelberg, 2015 | ||
| 690 | 7 | |a Decomposition reaction |2 nationallicence | |
| 690 | 7 | |a Variational transition-state theory |2 nationallicence | |
| 690 | 7 | |a Rate constant |2 nationallicence | |
| 700 | 1 | |a Liu |D Yan |u Key Laboratory of Dual-Use Materials, Weinan Normal University, 714099, Weinan, Shaanxi, People's Republic of China |4 aut | |
| 700 | 1 | |a Su |D Kehe |u Key Laboratory of Space Applied Physics and Chemistry of the Ministry of Education, School of Natural and Applied Sciences, Northwestern Polytechnical University, 710072, Xi'an, Shaanxi, People's Republic of China |4 aut | |
| 700 | 1 | |a Zeng |D Qingfeng |u National Key Laboratory of Thermostructure Composite Materials, Northwestern Polytechnical University, 710072, Xi'an, Shaanxi, People's Republic of China |4 aut | |
| 700 | 1 | |a Cheng |D Laifei |u National Key Laboratory of Thermostructure Composite Materials, Northwestern Polytechnical University, 710072, Xi'an, Shaanxi, People's Republic of China |4 aut | |
| 700 | 1 | |a Zhang |D Litong |u National Key Laboratory of Thermostructure Composite Materials, Northwestern Polytechnical University, 710072, Xi'an, Shaanxi, People's Republic of China |4 aut | |
| 773 | 0 | |t Theoretical Chemistry Accounts |d Springer Berlin Heidelberg |g 134/8(2015-08-01), 1-9 |x 1432-881X |q 134:8<1 |1 2015 |2 134 |o 214 | |
| 856 | 4 | 0 | |u https://doi.org/10.1007/s00214-015-1698-3 |q text/html |z Onlinezugriff via DOI |
| 898 | |a BK010053 |b XK010053 |c XK010000 | ||
| 900 | 7 | |a Metadata rights reserved |b Springer special CC-BY-NC licence |2 nationallicence | |
| 908 | |D 1 |a research-article |2 jats | ||
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| 950 | |B NATIONALLICENCE |P 856 |E 40 |u https://doi.org/10.1007/s00214-015-1698-3 |q text/html |z Onlinezugriff via DOI | ||
| 950 | |B NATIONALLICENCE |P 700 |E 1- |a Liu |D Yan |u Key Laboratory of Dual-Use Materials, Weinan Normal University, 714099, Weinan, Shaanxi, People's Republic of China |4 aut | ||
| 950 | |B NATIONALLICENCE |P 700 |E 1- |a Su |D Kehe |u Key Laboratory of Space Applied Physics and Chemistry of the Ministry of Education, School of Natural and Applied Sciences, Northwestern Polytechnical University, 710072, Xi'an, Shaanxi, People's Republic of China |4 aut | ||
| 950 | |B NATIONALLICENCE |P 700 |E 1- |a Zeng |D Qingfeng |u National Key Laboratory of Thermostructure Composite Materials, Northwestern Polytechnical University, 710072, Xi'an, Shaanxi, People's Republic of China |4 aut | ||
| 950 | |B NATIONALLICENCE |P 700 |E 1- |a Cheng |D Laifei |u National Key Laboratory of Thermostructure Composite Materials, Northwestern Polytechnical University, 710072, Xi'an, Shaanxi, People's Republic of China |4 aut | ||
| 950 | |B NATIONALLICENCE |P 700 |E 1- |a Zhang |D Litong |u National Key Laboratory of Thermostructure Composite Materials, Northwestern Polytechnical University, 710072, Xi'an, Shaanxi, People's Republic of China |4 aut | ||
| 950 | |B NATIONALLICENCE |P 773 |E 0- |t Theoretical Chemistry Accounts |d Springer Berlin Heidelberg |g 134/8(2015-08-01), 1-9 |x 1432-881X |q 134:8<1 |1 2015 |2 134 |o 214 | ||