Isotope separation in chemical reactions of vibrationally excited molecules

Gordiet︠s︡, B. F.; Mamedov, Sh. S.

doi:10.1070/qe1975v005n09abeh011907

“…The voltage of the discharge was controlled by the transformer up to 9 kV and a 50 Hz glow discharge was applied between two stainless steel electrodes, spaced 50 cm apart. The conditions for discharge were as follows: discharge pressure was 0.27 to 1.33 kPa, discharge voltage was 3 to 9 kV, discharge current was 0.5 to 5 mA, and total gas flow rate was 10 to 200 cm 3 /min (at 101.3 kPa, 293.15 K). Carbon isotopic contents of products relative to those of reactants were measured by quadru-pole mass spectrometer.…”

Section: Methodsmentioning

confidence: 99%

“…However, the enrichment coefficient is rather low contrary to our expected values based on the theoretical predictions. [3][4][5] The other thing which has to be noticed here is the consistent relations among enrichment coefficients in products such as:…”

Section: Enrichment Coefficientsmentioning

confidence: 99%

“…[3][4][5][6][7][8][9][10][11][12] Theoretical analyses have shown its attractive potential that in such process the reaction yield and enrichment factor are relatively high and the energy expenditure per separated atom is quite low. [3][4][5][6] And a few experimental studies have shown a high isotope enrichment potential. [7][8][9] Much of this early work is reviewed by Rich and Bergman. 11)…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Carbon and Oxygen Isotope Separation by Plasma Chemical Reactions in Carbon Monoxide Glow Discharge

Mori

¹

,

Akatsuka

²

,

Suzuki

³

2001

Journal of Nuclear Science and Technology

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The separation of carbon and oxygen isotopes in CO glow discharge has been studied. The isotope enrichment in the products was measured by quadru-pole mass spectrometer. The reaction yield and empirical formula of solid phase products were determined by the gas-volumetric analysis. The stable products obtained in our experiment are CO 2 and solid polymers formed on the discharge wall. The polymer consists of both carbon and oxygen and the oxygen/carbon mole ratio in the polymer is 0.35±0.05. The isotope enrichment coefficients show a strong negative dependence on discharge current though the relative reaction yields have an opposite tendency. Consequently, the maximum isotope enrichment coefficients for 13 C in wall deposit of 2.31 and for 18 O in CO 2 of 1.37 are obtained when the discharge current and the reaction yields are minimum in our experimental range. The experimental results of isotope enrichment have been compared with theoretical values estimated by an analytical model of literature. The dilution mechanism of the isotope enrichment of stable products is inferred from the isotopic distributions of 13 C and 18 O in products and theoretical predictions for isotope enrichment.

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“…Some studies on isotope effect in the vibrational kinetics have also been reported. However, those studies are devoted mainly to the isotope disproportion in vibrationally excited molecules 11,13,16,17) and a few studies have been made on the isotope enrichment in reaction products: McLaughlin et al calculated the 15 N isotope enrichment of NO which is formed in the N 2 /O 2 discharge 18) and Akulintsev et al calculated the 13 C isotope enrichment of CO 2 and C products which are formed through the reaction CO(v)+CO(w)→CO 2 +C in the vibrationally excited CO molecules. 12) In the Akulintsev's study, however, the successive reactions of CO 2 and C products with other species and electron impact reactions were not considered.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Carbon Isotope Separation by Plasma Chemical Reactions in Carbon Monoxide Glow Discharge

Mori

¹

,

Akatsuka

²

,

Suzuki

³

2002

Journal of Nuclear Science and Technology

View full text Add to dashboard Cite

The separation of carbon isotopes in CO glow discharge has been studied, in which the formation of stable products enriched in 13 C is analyzed by the numerical simulation of kinetic model. Vibrational kinetics and vibrationally induced chemical reaction of CO molecules are considered in the kinetic model as well as electron impact reactions and isotope scrambling reactions of isotopically enriched products. The reaction yield and final isotope enrichment of the stable products are derived as a function of mean electron energy. When mean electron energy is 2.1 eV in the case of Maxwellian electron energy distribution and 3.3 eV in the case of Druyvesteyn one, the kinetic model can reproduce experimental isotope enrichment of precipitated carbon atoms in discharge reactor. The calculation suggests optimum mean electron energy of the plasma for isotope separation as 1.0 eV and, in this case, it is expected that 13 C enrichment coefficient for precipitated carbon atoms is about 10 and its reaction yield is about 0.5%.

show abstract

“…Some studies on isotope effect in the vibrational kinetics have also been reported. However, those studies are devoted mainly to the isotope disproportion in vibrationally excited molecules 11,13,16,17) and a few studies have been made on the isotope enrichment in reaction products: McLaughlin et al calculated the 15 N isotope enrichment of NO which is formed in the N 2 /O 2 discharge 18) and Akulintsev et al calculated the 13 C isotope enrichment of CO 2 and C products which are formed through the reaction CO(v)+CO(w)→CO 2 +C in the vibrationally excited CO molecules. 12) In the Akulintsev's study, however, the successive reactions of CO 2 and C products with other species and electron impact reactions were not considered.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Carbon Isotope Separation by Plasma Chemical Reactions in Carbon Monoxide Glow Discharge.

Mori

¹

,

Akatsuka

²

,

Suzuki

³

2002

J. Nucl. Sci. Technol.

1

0

View full text Add to dashboard Cite

The separation of carbon isotopes in CO glow discharge has been studied, in which the formation of stable products enriched in 13 C is analyzed by the numerical simulation of kinetic model. Vibrational kinetics and vibrationally induced chemical reaction of CO molecules are considered in the kinetic model as well as electron impact reactions and isotope scrambling reactions of isotopically enriched products. The reaction yield and final isotope enrichment of the stable products are derived as a function of mean electron energy. When mean electron energy is 2.1 eV in the case of Maxwellian electron energy distribution and 3.3 eV in the case of Druyvesteyn one, the kinetic model can reproduce experimental isotope enrichment of precipitated carbon atoms in discharge reactor. The calculation suggests optimum mean electron energy of the plasma for isotope separation as 1.0 eV and, in this case, it is expected that 13 C enrichment coefficient for precipitated carbon atoms is about 10 and its reaction yield is about 0.5%.

show abstract

Isotope separation in chemical reactions of vibrationally excited molecules

Cited by 25 publications

References 0 publications

Carbon and Oxygen Isotope Separation by Plasma Chemical Reactions in Carbon Monoxide Glow Discharge

Carbon and Oxygen Isotope Separation by Plasma Chemical Reactions in Carbon Monoxide Glow Discharge

Numerical Analysis of Carbon Isotope Separation by Plasma Chemical Reactions in Carbon Monoxide Glow Discharge

Numerical Analysis of Carbon Isotope Separation by Plasma Chemical Reactions in Carbon Monoxide Glow Discharge.

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