1
|
Zhang H, Zhu F, Li X, Cen K, Du C, Tu X. Enhanced hydrogen production by methanol decomposition using a novel rotating gliding arc discharge plasma. RSC Adv 2016. [DOI: 10.1039/c5ra26343c] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hydrogen production from methanol decomposition was performed in a novel direct current (DC) rotating gliding arc (RGA) plasma reactor.
Collapse
Affiliation(s)
- Hao Zhang
- State Key Laboratory of Clean Energy Utilization
- Zhejiang University
- Hangzhou 310027
- China
| | - Fengsen Zhu
- State Key Laboratory of Clean Energy Utilization
- Zhejiang University
- Hangzhou 310027
- China
| | - Xiaodong Li
- State Key Laboratory of Clean Energy Utilization
- Zhejiang University
- Hangzhou 310027
- China
| | - Kefa Cen
- State Key Laboratory of Clean Energy Utilization
- Zhejiang University
- Hangzhou 310027
- China
| | - Changming Du
- School of Environmental Science and Engineering
- Sun Yat-Sen University
- Guangdong 510275
- China
| | - Xin Tu
- Department of Electrical Engineering and Electronics
- University of Liverpool
- Liverpool L69 3GJ
- UK
| |
Collapse
|
2
|
Wang S, Li S, Davidson DF, Hanson RK. Shock Tube Measurement of the High-Temperature Rate Constant for OH + CH3 → Products. J Phys Chem A 2015; 119:8799-805. [PMID: 26230910 DOI: 10.1021/acs.jpca.5b05725] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reaction between hydroxyl (OH) and methyl radicals (CH3) is critical to hydrocarbon oxidation. Motivated by the sparseness of its high-temperature rate constant data and the large uncertainties in the existing literature values, the current study has remeasured the overall rate constant of the OH + CH3 reaction and extended the measurement temperature range to 1214-1933 K, using simultaneous laser absorption diagnostics for OH and CH3 radicals behind incident and reflected shock waves. tert-Butyl hydroperoxide and azomethane were used as pyrolytic sources for the OH and CH3 radicals, respectively. The current study bridged the temperature ranges of existing experimental data, and good agreement is seen between the current measurement and some previous experimental and theoretical high-temperature studies. A recommendation for the rate constant expression of the title reaction, based on the weighted average of the high-temperature data from selected studies, is given by k1 = 4.19 × 10(1)(T/K)(3.15) exp(5270 K/T) cm(3) mol(-1) s(-1) ±30%, which is valid over 1000-2500 K.
Collapse
Affiliation(s)
- Shengkai Wang
- High Temperature Gasdynamics Laboratory, Mechanical Engineering Department, Stanford University, Stanford, California 94305, United States
| | - Sijie Li
- High Temperature Gasdynamics Laboratory, Mechanical Engineering Department, Stanford University, Stanford, California 94305, United States
| | - David F Davidson
- High Temperature Gasdynamics Laboratory, Mechanical Engineering Department, Stanford University, Stanford, California 94305, United States
| | - Ronald K Hanson
- High Temperature Gasdynamics Laboratory, Mechanical Engineering Department, Stanford University, Stanford, California 94305, United States
| |
Collapse
|
3
|
Sangwan M, Yan C, Chesnokov EN, Krasnoperov LN. Reaction CH3 + CH3 → C2H6 Studied over the 292–714 K Temperature and 1–100 bar Pressure Ranges. J Phys Chem A 2015; 119:7847-57. [DOI: 10.1021/acs.jpca.5b01276] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Manuvesh Sangwan
- Department
of Chemistry and Environmental Science, New Jersey Institute of Technology, University Heights, Newark, New Jersey 07102, United States
| | - Chao Yan
- Department
of Chemistry and Environmental Science, New Jersey Institute of Technology, University Heights, Newark, New Jersey 07102, United States
| | | | - Lev N. Krasnoperov
- Department
of Chemistry and Environmental Science, New Jersey Institute of Technology, University Heights, Newark, New Jersey 07102, United States
| |
Collapse
|
4
|
Peukert SL, Michael JV. High-Temperature Shock Tube and Modeling Studies on the Reactions of Methanol with D-Atoms and CH3-Radicals. J Phys Chem A 2013; 117:10186-95. [DOI: 10.1021/jp4059005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- S. L. Peukert
- Chemical
Sciences and Engineering
Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - J. V. Michael
- Chemical
Sciences and Engineering
Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| |
Collapse
|
5
|
A Hierarchical and Comparative Kinetic Modeling Study of C1
− C2
Hydrocarbon and Oxygenated Fuels. INT J CHEM KINET 2013. [DOI: 10.1002/kin.20802] [Citation(s) in RCA: 773] [Impact Index Per Article: 70.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
6
|
Peukert SL, Sivaramakrishnan R, Michael JV. High Temperature Shock Tube Studies on the Thermal Decomposition of O3 and the Reaction of Dimethyl Carbonate with O-Atoms. J Phys Chem A 2013; 117:3729-38. [DOI: 10.1021/jp400613p] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- S. L. Peukert
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439,
United States
| | - R. Sivaramakrishnan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439,
United States
| | - J. V. Michael
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439,
United States
| |
Collapse
|
7
|
|
8
|
Affiliation(s)
- Chen Qu
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University , Atlanta, Georgia, USA
| | - Joel M. Bowman
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University , Atlanta, Georgia, USA
| |
Collapse
|
9
|
Lee PF, Matsui H, Xu DW, Wang NS. Thermal Decomposition and Oxidation of CH3OH. J Phys Chem A 2013; 117:525-34. [DOI: 10.1021/jp309745p] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pei-Fang Lee
- Department of Applied Chemistry, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010,
Taiwan
| | - Hiroyuki Matsui
- Department of Applied Chemistry, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010,
Taiwan
| | - Ding-Wei Xu
- Department of Applied Chemistry, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010,
Taiwan
| | - Niann-Shiah Wang
- Department of Applied Chemistry, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010,
Taiwan
| |
Collapse
|
10
|
Sangwan M, Chesnokov EN, Krasnoperov LN. Reaction CH3 + OH Studied over the 294–714 K Temperature and 1–100 bar Pressure Ranges. J Phys Chem A 2012; 116:8661-70. [DOI: 10.1021/jp305070c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Manuvesh Sangwan
- Department of Chemistry
and Environmental Science, New Jersey Institute of Technology, University Heights, Newark, New Jersey
07102, United States
| | | | - Lev N. Krasnoperov
- Department of Chemistry
and Environmental Science, New Jersey Institute of Technology, University Heights, Newark, New Jersey
07102, United States
| |
Collapse
|
11
|
LÜ YJ, YAN WJ, HU SH, WANG BW. Hydrogen production by methanol decomposition using gliding arc gas discharge. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/s1872-5813(12)60025-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
12
|
Pang GA, Hanson RK, Golden DM, Bowman CT. High-Temperature Measurements of the Rate Constants for Reactions of OH with a Series of Large Normal Alkanes: n-Pentane, n-Heptane, and n-Nonane. ACTA ACUST UNITED AC 2011. [DOI: 10.1524/zpch.2011.0156] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
Rate constants for the overall reactions of OH with n-pentane, n-heptane, and n-nonane were measured in shock tube experiments behind reflected shock waves. Narrow-linewidth laser absorption by OH at 306.7 nm was used in pseudo first-order experiments with temperatures between 869 to 1364 K. tert-Butyl hydroperoxide (TBHP) was used as the OH precursor. Experiments were also performed to study the kinetics of the TBHP decomposition and resulting product chemistry, and an accurate mechanism describing OH precursor chemistry effects was developed to model OH concentration time-history in the n-alkane + OH experiments. The experimental results for the n-alkane + OH rate constant measurements can be expressed as rate constants in Arrhenius form as
k
n-pentane + OH = 2.10 × 10-10 exp(-2038/T[K]) (869–1364 K),
k
n-heptane + OH = 2.43 × 10-10 exp(-1804/T[K]) (869–1364 K),
k
n-nonane + OH = 3.17 × 10-10 exp(-1801/T[K]) (884–1352 K),
each in units of cm3 molecule-1 s-1. The present rate constants measured for OH with n-pentane and n-heptane show agreement within 20% with recent work by Sivaramakrishnan and Michael [J. Phys. Chem. A, 113 (2009) 5047]. The measurements of the rate constant for n-nonane + OH presented here represent the first in the literature to depict the temperature dependence of the rate constant above 800 K. The measurements of each n-alkane + OH rate constant studied were compared with two models in the literature used to estimate the rate constants of n-alkane + OH reactions. The Structure-Activity Relationship of Kwok and Atkinson [Atmos. Environ., 29 (1995) 1685] shows the best agreement with the current data for all three n-alkanes over the entire temperature range studied, demonstrating that this model is capable of predicting the overall rate constants for reactions of OH with n-pentane, n-heptane, and n-nonane for temperatures up to 1364 K.
Collapse
Affiliation(s)
| | - Ronald K. Hanson
- Stanford University, Mechanical Engineering Department, Stanford, CA 94305, U.S.A
| | - David M. Golden
- Stanford University, Department of Mechanical Engineering, Stanford CA 94305, U.S.A
| | | |
Collapse
|
13
|
|
14
|
|
15
|
Lu KW, Matsui H, Huang CL, Raghunath P, Wang NS, Lin MC. Shock Tube Study on the Thermal Decomposition of CH3OH. J Phys Chem A 2010; 114:5493-502. [DOI: 10.1021/jp100535r] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ku-We Lu
- Department of Applied Chemistry, National Chiao Tung University, 1001, Ta Hsuch Road, Hsinchu 30010 Taiwan
| | - Hiroyuki Matsui
- Department of Applied Chemistry, National Chiao Tung University, 1001, Ta Hsuch Road, Hsinchu 30010 Taiwan
| | - Ching-Liang Huang
- Department of Applied Chemistry, National Chiao Tung University, 1001, Ta Hsuch Road, Hsinchu 30010 Taiwan
| | - P. Raghunath
- Department of Applied Chemistry, National Chiao Tung University, 1001, Ta Hsuch Road, Hsinchu 30010 Taiwan
| | - Niann-Shiah Wang
- Department of Applied Chemistry, National Chiao Tung University, 1001, Ta Hsuch Road, Hsinchu 30010 Taiwan
| | - M. C. Lin
- Department of Applied Chemistry, National Chiao Tung University, 1001, Ta Hsuch Road, Hsinchu 30010 Taiwan
| |
Collapse
|
16
|
Vasudevan V, Cook RD, Hanson RK, Bowman CT, Golden DM. High-temperature shock tube study of the reactions CH3 + OH → products and CH3OH + Ar → products. INT J CHEM KINET 2008. [DOI: 10.1002/kin.20334] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
17
|
Jasper AW, Klippenstein SJ, Harding LB. Secondary Kinetics of Methanol Decomposition: Theoretical Rate Coefficients for 3CH2 + OH, 3CH2 + 3CH2, and 3CH2 + CH3. J Phys Chem A 2007; 111:8699-707. [PMID: 17696414 DOI: 10.1021/jp0736950] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Direct variable reaction coordinate transition state theory (VRC-TST) rate coefficients are reported for the (3)CH(2) + OH, (3)CH(2) + (3)CH(2), and (3)CH(2) + CH(3) barrierless association reactions. The predicted rate coefficient for the (3)CH(2) + OH reaction (approximately 1.2 x 10(-10) cm(3) molecule(-1) s(-1) for 300-2500 K) is 4-5 times larger than previous estimates, indicating that this reaction may be an important sink for OH in many combustion systems. The predicted rate coefficients for the (3)CH(2) + CH(3) and (3)CH(2) + (3)CH(2) reactions are found to be in good agreement with the range of available experimental measurements. Product branching in the self-reaction of methylene is discussed, and the C(2)H(2) + 2H and C(2)H(2) + H2 products are predicted in a ratio of 4:1. The effect of the present set of rate coefficients on modeling the secondary kinetics of methanol decomposition is briefly considered. Finally, the present set of rate coefficients, along with previous VRC-TST determinations of the rate coefficients for the self-reactions of CH(3) and OH and for the CH(3) + OH reaction, are used to test the geometric mean rule for the CH(3), (3)CH(2), and OH fragments. The geometric mean rule is found to predict the cross-combination rate coefficients for the (3)CH(2) + OH and (3)CH(2) + CH(3) reactions to better than 20%, with a larger (up to 50%) error for the CH(3) + OH reaction.
Collapse
Affiliation(s)
- Ahren W Jasper
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
| | | | | |
Collapse
|
18
|
Jasper AW, Klippenstein SJ, Harding LB, Ruscic B. Kinetics of the Reaction of Methyl Radical with Hydroxyl Radical and Methanol Decomposition. J Phys Chem A 2007; 111:3932-50. [PMID: 17388366 DOI: 10.1021/jp067585p] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The CH3 + OH bimolecular reaction and the dissociation of methanol are studied theoretically at conditions relevant to combustion chemistry. Kinetics for the CH3 + OH barrierless association reaction and for the H + CH2OH and H + CH3O product channels are determined in the high-pressure limit using variable reaction coordinate transition state theory and multireference electronic structure calculations to evaluate the fragment interaction energies. The CH3 + OH --> 3CH2 + H2O abstraction reaction and the H2 + HCOH and H2 + H2CO product channels feature localized dynamical bottlenecks and are treated using variational transition state theory and QCISD(T) energies extrapolated to the complete basis set limit. The 1CH2 + H2O product channel has two dynamical regimes, featuring both an inner saddle point and an outer barrierless region, and it is shown that a microcanonical two-state model is necessary to properly describe the association rate for this reaction over a broad temperature range. Experimental channel energies for the methanol system are reevaluated using the Active Thermochemical Tables (ATcT) approach. Pressure dependent, phenomenological rate coefficients for the CH3 + OH bimolecular reaction and for methanol decomposition are determined via master equation simulations. The predicted results agree well with experimental results, including those from a companion high-temperature shock tube determination for the decomposition of methanol.
Collapse
Affiliation(s)
- Ahren W Jasper
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | | | | | | |
Collapse
|
19
|
Srinivasan NK, Su MC, Michael JV. High-temperature rate constants for CH3OH + Kr --> products, OH + CH3OH --> products, OH + (CH3)(2)CO --> CH2COCH3 + H2O, and OH + CH3 --> CH) + H2O. J Phys Chem A 2007; 111:3951-8. [PMID: 17388365 DOI: 10.1021/jp0673516] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reflected shock tube technique with multipass absorption spectrometric detection of OH radicals at 308 nm (corresponding to a total path length of approximately 4.9 m) has been used to study the dissociation of methanol between 1591 and 2865 K. Rate constants for two product channels [CH3OH + Kr --> CH3 + OH + Kr (1) and CH3OH + Kr --> 1CH2 + H2O + Kr (2)] were determined. During the course of the study, it was necessary to determine several other rate constants that contributed to the profile fits. These include OH + CH3OH --> products, OH + (CH3)2CO --> CH2COCH3 + H2O, and OH + CH3 --> 1,3CH2 + H2O. The derived expressions, in units of cm(3) molecule(-1) s(-1), are k(1) = 9.33 x 10(-9) exp(-30857 K/T) for 1591-2287 K, k(2) = 3.27 x 10(-10) exp(-25946 K/T) for 1734-2287 K, kOH+CH3OH = 2.96 x 10-16T1.4434 exp(-57 K/T) for 210-1710 K, k(OH+(CH3)(2)CO) = (7.3 +/- 0.7) x 10(-12) for 1178-1299 K and k(OH+CH3) = (1.3 +/- 0.2) x 10(-11) for 1000-1200 K. With these values along with other well-established rate constants, a mechanism was used to obtain profile fits that agreed with experiment to within <+/-10%. The values obtained for reactions 1 and 2 are compared with earlier determinations and also with new theoretical calculations that are presented in the preceding article in this issue. These new calculations are in good agreement with the present data for both (1) and (2) and also for OH + CH3 --> products.
Collapse
Affiliation(s)
- N K Srinivasan
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | | | | |
Collapse
|
20
|
Schofield K, Steinberg M. CH and C2 Measurements Imply a Radical Pool within a Pool in Acetylene Flames. J Phys Chem A 2007; 111:2098-114. [PMID: 17388296 DOI: 10.1021/jp0667689] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Measured CH and C2 profiles show a striking resemblance as a function of time in a series of seven well-characterized fuel-rich (phi=1.2-2.0) non-sooting acetylene flames. This implied commonality and interrelationship are unexpected as these radicals have dissimilar chemical kinetic natures. As a result, a rigorous examination was undertaken of the behavior of each of the hydrocarbon species known to be present, C, CH, CH2, CH3, CH4, CHO, CHOH, CH2O, CH2OH, CH3O, CH3OH, C2, C2H, C2H2, CHCO, CH2CO, and C2O. This emphasized the main region where CH and C2 are observed (50-600 micros) and reduced the kinetic reactions to only those that operate efficiently and are dominant. It was immediately apparent that this region of the flame reflects the nature of a hydrogen flame heavily doped with CO and CO2 and containing traces of hydrocarbons. The radical species, H, OH, O, along with H2, H2O, and O2, form an important controlling radical pool that is in partial equilibrium, and the concentrations of each of the hydrocarbon radicals are minor to this, playing secondary roles. As a result, the dominant fast reactions are those between the hydrocarbons and the basic hydrogen/oxygen radicals. Hydrocarbon-hydrocarbon reactions are unimportant here at these equivalence ratios. CH and C2 are formed and destroyed on a sub-microsecond time scale so that their flame profiles are the reflection of a complex kinetically dynamic system. This is found to be the case for all of the hydrocarbon species examined. As might be expected, these rapidly form steady-state distributions. However, with the exceptions of C, CHO, CHOH, and CH2O, which are irreversibly being oxidized, the others all form an interconnected hydrocarbon pool that is under the control of the larger hydrogen radical pool. The hydrocarbon pool can rapidly adjust, and the CH and C2 decay together as the pool is drained. This is either by continuing oxidation in less rich mixtures, or in richer flames where this is negligible by the onset of hydrocarbon-hydrocarbon reactions. The implications of such a hydrocarbon pool are significant. It introduces a buffering effect on their distribution and provides the indirect connection between CH and C2. Moreover, because they are members of this radical pool, flame studies alone cannot answer questions concerning their specific importance in combustion other than their contributing role to this pool. The presence of such a pool modifies the exactness that is needed for kinetic mechanisms, and knowledge of every species in the system no longer is necessary. Furthermore, as rate constants become refined, it will allow for the calculation of the relative concentrations of the hydrocarbon species and facilitate reduced kinetic mechanisms. It provides an explanation for previous isotopically labeled experiments and illustrates the difficulty of exactly identifying in flames the role of individual species. It resolves the fact that differing kinetic models can show similar levels of accuracy and has implications for sensitivity analyses. It finally unveils the mechanism of the flame ionization detector and has implications for the differing interpretations of diamond formation mechanisms.
Collapse
Affiliation(s)
- Keith Schofield
- Materials Research Laboratory, University of California, Santa Barbara, California 93106-5121, USA.
| | | |
Collapse
|
21
|
Li J, Zhao Z, Kazakov A, Chaos M, Dryer FL, Scire JJ. A comprehensive kinetic mechanism for CO, CH2O, and CH3OH combustion. INT J CHEM KINET 2007. [DOI: 10.1002/kin.20218] [Citation(s) in RCA: 588] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
22
|
Srinivasan NK, Su MC, Michael JV. Reflected shock tube studies of high-temperature rate constants for OH + C2H2 and OH + C2H4. Phys Chem Chem Phys 2007; 9:4155-63. [PMID: 17687465 DOI: 10.1039/b702267k] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reflected shock tube technique with multi-pass absorption spectrometric detection of OH-radicals at 308 nm (corresponding to a total path length of approximately 4.9 m) has been used to study the reactions, OH + C(2)H(2)--> products (1) and OH + C(2)H(4)--> C(2)H(3) + H(2)O (2). The present optical configuration gives a S/N ratio of approximately 1 at approximately 0.5-1.0 x 10(12) radicals cm(-3). Hence, kinetics experiments could be performed at [OH](0) = approximately 4-20 ppm thereby minimizing secondary reactions. OH was produced rapidly from the dissociations of either CH(3)OH or NH(2)OH (hydroxylamine). A mechanism was then used to obtain profile fits that agreed with the experiment to within <+/-5%. The derived Arrhenius expressions, in units of cm(3) molecule(-1) s(-1) are: k(1) = (1.03 +/- 0.24) x 10(-10) exp(-7212 +/- 417 K/T) for 1509-2362 K and k(2) = (10.2 +/- 5.8) x 10(-10) exp(-7411 +/- 871 K/T) for 1463-1931 K. The present study is the first ever direct measurement for reaction (1) at temperatures >1275 K while the present results extend the temperature range for (2) by approximately 700 K. These values are compared with earlier determinations and with recent theoretical calculations. The calculations agree with the present data for both reactions to within +/-10% over the entire T-range.
Collapse
Affiliation(s)
- N K Srinivasan
- Chemistry Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | | | | |
Collapse
|
23
|
Huang L, Dong W, Zhang R, Hou H. Investigation of a new approach to decompose two potent greenhouse gases: photoreduction of SF(6) and SF(5)CF(3) in the presence of acetone. CHEMOSPHERE 2007; 66:833-40. [PMID: 16860846 DOI: 10.1016/j.chemosphere.2006.06.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 06/12/2006] [Accepted: 06/13/2006] [Indexed: 05/11/2023]
Abstract
In this paper, we addressed the utilization of photochemical method as an innovative technology for the destruction and removal of two potent greenhouse gases, SF(6) and SF(5)CF(3). The destruction and removal efficiency (DRE) of the process was determined as a function of excitation wavelength, irradiation time, initial ratio of acetone to SF(5)X (X represented F or CF(3)), initial SF(5)X concentration, additive oxygen and water vapor concentration. A complete removal was achieved by a radiation period of 55min and 120min for SF(6)-CH(3)COCH(3) system and SF(5)CF(3)-CH(3)COCH(3) system respectively under 184.9nm irradiation. Extra addition of water vapor can enhance DRE by approximately 6% points in both systems. Further studies with GC/MS and FT-IR proved that no hazardous products such as S(2)F(10), SO(2)F(2), SOF(2), SOF(4) were generated in this process.
Collapse
Affiliation(s)
- Li Huang
- Institute of Environmental Science, Fudan University, Shanghai 200433, People's Republic of China
| | | | | | | |
Collapse
|
24
|
Han Y, Wang JG, Cheng DG, Liu CJ. Density Functional Theory Study of Methanol Conversion via Cold Plasmas. Ind Eng Chem Res 2006. [DOI: 10.1021/ie060132m] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- You Han
- Key Laboratory of Green Chemical Technology, School of Chemical Engineering, Tianjin University, Tianjin 300072, People's Republic of China
| | - Jian-guo Wang
- Key Laboratory of Green Chemical Technology, School of Chemical Engineering, Tianjin University, Tianjin 300072, People's Republic of China
| | - Dang-guo Cheng
- Key Laboratory of Green Chemical Technology, School of Chemical Engineering, Tianjin University, Tianjin 300072, People's Republic of China
| | - Chang-jun Liu
- Key Laboratory of Green Chemical Technology, School of Chemical Engineering, Tianjin University, Tianjin 300072, People's Republic of China
| |
Collapse
|
25
|
Srinivasan NK, Su MC, Sutherland JW, Michael JV. Reflected Shock Tube Studies of High-Temperature Rate Constants for CH3 + O2, H2CO + O2, and OH + O2. J Phys Chem A 2005; 109:7902-14. [PMID: 16834172 DOI: 10.1021/jp0581330] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The reflected shock tube technique with multipass absorption spectrometric detection of OH-radicals at 308 nm, corresponding to a total path length of approximately 2.8 m, has been used to study the reaction CH3 + O2 CH2O + OH. Experiments were performed between 1303 and 2272 K, using ppm quantities of CH3I (methyl source) and 5-10% O2, diluted with Kr as the bath gas at test pressures less than 1 atm. We have also reanalyzed our earlier ARAS measurements for the atomic channel (CH3 + O2 --> CH3O + O) and have compared both these results with other earlier studies to derive a rate expression of the Arrhenius form. The derived expressions, in units of cm3 molecule(-1) s(-1), are k = 3.11 x 10(-13) exp(-4953 K/T) over the T-range 1237-2430 K, for the OH-channel, and k = 1.253 x 10(-11) exp(-14241 K/T) over the T-range 1250-2430 K, for the O-atom channel. Since CH2O is a major product in both reactions, reliable rates for the reaction CH2O + O2 --> HCO + HO2 could be derived from [OH]t and [O]t experiments over the T-range 1587-2109 K. The combined linear least-squares fit result, k = 1.34 x 10(-8) exp(-26883 K/T) cm3 molecule(-1) s(-1), and a recent VTST calculation clearly overlap within the uncertainties in both studies. Finally, a high sensitivity for the reaction OH + O2 --> HO2 + O was noted at high temperature in the O-atom data set simulations. The values for this obtained by fitting the O-atom data sets at later times (approximately 1.2 ms) again follow the Arrhenius form, k = 2.56 x 10(-10) exp(-24145 K/T) cm3 molecule(-1) s(-1), over the T-range, 1950-2100 K.
Collapse
Affiliation(s)
- N K Srinivasan
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | | | | | | |
Collapse
|
26
|
Srinivasan NK, Su MC, Sutherland JW, Michael JV. Reflected Shock Tube Studies of High-Temperature Rate Constants for OH + CH4 → CH3 + H2O and CH3 + NO2 → CH3O + NO. J Phys Chem A 2005; 109:1857-63. [PMID: 16833517 DOI: 10.1021/jp040679j] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reflected shock tube technique with multipass absorption spectrometric detection of OH radicals at 308 nm has been used to study the reactions OH + CH(4) --> CH(3) + H(2)O and CH(3) + NO(2) --> CH(3)O + NO. Over the temperature range 840-2025 K, the rate constants for the first reaction can be represented by the Arrhenius expression k = (9.52 +/- 1.62) x 10(-11) exp[(-4134 +/- 222 K)/T] cm(3) molecule(-1) s(-1). Since this reaction is important in both combustion and atmospheric chemistry, there have been many prior investigations with a variety of techniques. The present results extend the temperature range by 500 K and have been combined with the most accurate earlier studies to derive an evaluation over the extended temperature range 195-2025 K. A three-parameter expression describes the rate behavior over this temperature range, k = (1.66 x 10(-18))T(2.182) exp[(-1231 K)/T] cm(3) molecule(-1) s(-1). Previous theoretical studies are discussed, and the present evaluation is compared to earlier theoretical estimates. Since CH(3) radicals are a product of the reaction and could cause secondary perturbations in rate constant determinations, the second reaction was studied by OH radical production from the fast reactions CH(3)O --> CH(2)O + H and H + NO(2) --> OH + NO. The measured rate constant is 2.26 x 10(-11) cm(3) molecule(-1) s(-1) and is not dependent on temperature from 233 to 1700 K within experimental error.
Collapse
Affiliation(s)
- N K Srinivasan
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | | | | | | |
Collapse
|