Lithium Isotope Effect Accompanying Electrochemical Insertion of Lithium into Liquid Gallium

2010 ◽  
Vol 65 (5) ◽  
pp. 461-467 ◽  
Author(s):  
Keita Zenzai ◽  
Ayaka Yasui ◽  
Satoshi Yanase ◽  
Takao Oi
Keyword(s):  
Isotope Effect ◽  
Isotope Effects ◽  
Isotope Separation ◽  
Ethylene Carbonate ◽  
Quantitative Agreement ◽  
Liquid Gallium ◽  
Molecular Orbital Calculations ◽  
Lithium Isotope ◽  
Mixed Solution ◽  
Separation Factors

Lithium was electrochemically inserted from a 1 : 2 (v/v) mixed solution of ethylene carbonate (EC) and methylethyl carbonate (MEC) containing 1M LiClO4 into liquid gallium to observe lithium isotope effects accompanying the insertion. It was observed that the lighter isotope 6Li was preferentially fractionated into liquid gallium with the single-stage lithium isotope separation factors S, ranging from 1.005 to 1.031 at 50 °C and 1.003 to 1.024 at 25 °C. The lithium isotope effects estimated by molecular orbital calculations at the B3LYP/6-311G(d) level of theory agreed qualitatively with those of the experiments, but the quantitative agreement of the two was not satisfactory

Lithium Isotope Effect Accompanying Electrochemical Intercalation of Lithium into Graphite

2003 ◽  
Vol 58 (5-6) ◽  
pp. 306-312 ◽  
Author(s):  
Satoshi Yanase ◽  
Wakana Hayama ◽  
Takao Oi
Keyword(s):  
Isotope Effect ◽  
Separation Factor ◽  
Early Stage ◽  
Isotope Separation ◽  
Ethylene Carbonate ◽  
Lithium Ion ◽  
Lithium Isotope ◽  
Mixed Solution ◽  
Electrochemical Intercalation ◽  
Graphite Intercalation

Lithium has been electrochemically intercalated from a 1:2 (v/v) mixed solution of ethylene carbonate (EC) and methylethyl carbonate (MEC) containing 1 M LiClO4 into graphite, and the lithium isotope fractionation accompanying the intercalation was observed. The lighter isotope was preferentially fractionated into graphite. The single-stage lithium isotope separation factor ranged from 1.007 to 1.025 at 25 °C and depended little on the mole ratio of lithium to carbon of the lithium-graphite intercalation compounds (Li-GIC) formed. The separation factor inceased with the relative content of lithium. This dependence seems consistent with the existence of an equilibrium isotope effect between the solvated lithium ion in the EC/MEC electrolyte solution and the lithium in graphite, and with the formation of a solid electrolyte interfaces on graphite at the early stage of intercalation.

Ab initio Molecular Orbital Calculations of Reduced Partition Function Ratios of Hydrated Lithium Ions in Ion Exchange Systems

2001 ◽  
Vol 56 (3-4) ◽  
pp. 297-306 ◽  
Author(s):  
Satoshi Yanase ◽  
Takao Oi
Keyword(s):  
Partition Function ◽  
Ion Exchange ◽  
Molecular Orbital ◽  
Isotope Effects ◽  
Isotope Separation ◽  
Water Molecules ◽  
Molecular Orbital Calculations ◽  
Lithium Isotope ◽  
Lithium Ions ◽  
Additional Water

Abstract Molecular orbital (MO) calculations at the HF/6-31G(d) level were carried out for the aquolithium ions, Li+(H2O)n (n = 3, 4, 5, 6, 8, 10 and 12) and the aquolithium ions interacting with the methyl sul­fonate ion (MeS-), Li+MeS-(H2O)n (n = 0, 3,4, 5, 6, 7, 8 and 10) which were, respectively, intended to be substitutes for lithium species in the solution and resin phases of ion exchange systems for lithium isotope separation. For each of the species considered, at least one optimized structure with no negative frequency was obtained, and the 7Li-to-6Li isotopic reduced partition function ratio (RPFR) was esti­mated for the optimized structure. The solvation number in the primary solvation sphere was four, both in the solution and resin phases; three waters and MeS" formed the primary solvation sphere in the res­ in phase. Additional water molecules moved off to the secondary solvation sphere. It was found that consideration on the primary solvation sphere alone was insufficient for estimations of reduced parti­tion function ratios of aquolithium ions. Although the agreement between the experimentally obtained lithium isotope fractionation and the calculated results is not satisfactory, it is pointed out that the HF/6-31 G(d) level of the theory is usable for elucidation of lithium isotope effects in aqueous ion exchange systems.

Electrochemical Isotope Effect and Lithium Isotope Separation

2009 ◽  
Vol 131 (29) ◽  
pp. 9904-9905 ◽  
Author(s):  
Jay R. Black ◽  
Grant Umeda ◽  
Bruce Dunn ◽  
William F. McDonough ◽  
Abby Kavner
Keyword(s):  
Isotope Effect ◽  
Isotope Separation ◽  
Lithium Isotope

Lithium isotope separation factors of some two‐phase equilibrium systems

1976 ◽  
Vol 64 (4) ◽  
pp. 1828-1837 ◽  
Author(s):  
A. A. Palko ◽  
J. S. Drury ◽  
G. M. Begun
Keyword(s):  
Phase Equilibrium ◽  
Isotope Separation ◽  
Lithium Isotope ◽  
Two Phase ◽  
Separation Factors

Molecular Orbital Estimation of Reduced Partition Function Ratios of Lithium Interacting with Aromatic Hydrocarbons with Condensed Benzene Rings

2003 ◽  
Vol 58 (5-6) ◽  
pp. 325-332 ◽  
Author(s):  
Takao Oi ◽  
Satoshi Yanase
Keyword(s):  
Partition Function ◽  
Molecular Orbital ◽  
Aromatic Hydrocarbons ◽  
Lithium Atom ◽  
Isotope Effects ◽  
Molecular Orbital Calculations ◽  
Lithium Isotope ◽  
Graphene Layers ◽  
Stage Separation ◽  
Benzene Rings

Molecular orbital calculations at the B3LYP/6-311G(d) level were carried out to elucidate the lithium isotope effects accompanying chemical insertion of lithium from 1-methoxybutane solution containing lithium and naphthalene to graphite. The lithium atom between the graphene layers of graphite was modeled as lithium atoms in 1:1 complexes of lithium and simple aromatic hydrocarbons with condensed benzene rings. The 7Li-to-6Li isotopic reduced partition function ratio (RPFR) was found to be a decreasing function of the number of benzene rings adjacent to the benzene ring above which the lithium atom was located, and was “saturated” at 1.04570 at 25 °C. The most plausible lithium species in the 1-methoxybutane solution was a lithium atom interacting with a naphthalene molecule and solvated by a 1-methoxybutane molecule in the contact ion pair manner. Its RPFR value was 1.07126 at 25 °C. The two RPFR values gave a single-stage separation factor of 1.024 for the lithium isotopes, which agreed well with the experimental value of 1.023.

scholarly journals Anomalously large kinetic isotope effect

2007 ◽  
Vol 5 (4) ◽  
pp. 1019-1063 ◽  
Author(s):  
David Krinkin
Keyword(s):  
Isotope Effect ◽  
Kinetic Isotope Effect ◽  
Theoretical Study ◽  
Chemical Elements ◽  
Isotope Effects ◽  
Isotope Separation ◽  
Negative Influence ◽  
Rate Theory ◽  
Kinetic Isotope ◽  
Primary Problem

AbstractActivated diffusion of water between macromolecules in swollen cellulose is accompanied by anomalously high kinetic isotope effects of oxygen. The separation factor of heavy-oxygen water (H218O /H216O) is thousands of permilles instead of tens of permilles according to modern Absolute Rate Theory. This anomalous separation under usual conditions is disguised by the opposing process of very fast equalization to equilibrium through water-filled cellulose pores. This process is quicker by approximately 3 orders of magnitude than diffusion through the cellulose body. As a consequence, this opposition-directed equalization virtually eliminates the results of isotope separation. To reveal this anomaly it is necessary to suppress equalization, which was the primary problem for both discovery of this anomaly and its investigation. The method of investigating the anomalous separation in cellulose was developed with suppression of this negative influence. Discussion of the theoretical nature of the anomalous kinetic isotope effect is presented. This theoretical study would probably permit the discovery and use for isotope separation of the anomalously high isotope effect for other chemical elements, in particular, for those heavier than oxygen.

ADSORPTION EQUILIBRIA OF HYDROGEN, DEUTERIUM, AND THEIR MIXTURES. PART II

1960 ◽  
Vol 38 (1) ◽  
pp. 149-156 ◽  
Author(s):  
D. Basmadjian
Keyword(s):  
Isotope Separation ◽  
Zero Point ◽  
Isosteric Heat ◽  
Quantitative Agreement ◽  
Point Energy ◽  
Adsorption Equilibria ◽  
Separation Factors ◽  
Hydrogen Deuterium ◽  
Vertical Vibrations ◽  
Qualitative Discussion

An investigation has been made of the fundamental factors which determine isotope separation factors on adsorbents, based on hydrogen and deuterium isotherms reported in Part I. Through the use of a semiempirical thermodynamic approach, the binary separation factors α have been related to the single component isotherms (p = f(v)), and these in turn broken down into a number of terms involving the isosteric heat of adsorption q, temperature T, and surface coverage. If the less important contributions are neglected, the treatment leads to the following sequence of approximate relations:[Formula: see text]where ε0 = total vibrational zero-point energy of adsorbed molecules.The rigorous form of equation [I] agrees well with the experimental results, and semi-quantitative agreement with the data is shown by equation [II]. A qualitative discussion of [III] is given. It is suggested that the horizontal zero-point vibrations of the adsorbed species in some cases constitute an important contributing factor in addition to the vertical vibrations previously thought to be solely responsible for differences in isotope behavior.

Temperature Dependence of Lithium Isotope Effects in Ion Exchange Electromigration

1987 ◽  
Vol 42 (7) ◽  
pp. 709-712
Author(s):  
Yasuhiko Fujii ◽  
Morikazu Hosoe ◽  
Okamoto Makoto
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Isotope Effects ◽  
Isotope Separation ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Separation Coefficient ◽  
Lithium Isotope ◽  
Increasing Temperature ◽  
Exchange Membrane

The isotope separation coefficient of lithium electromigration through a cation exchange membrane is determined at 6, 11, 20 and 40 °C . It is found that this coefficient increases with temperature while the slope of the isotope distribution in the band decreases with increasing temperature. These tendencies are opposite to those usually observed in ion exchange chromatography.

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