• Korean Journal of Materials Research
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• v.31 no.8
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• pp.465-470
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• 2021

Deuterium is a crucial clean energy source required for nuclear fusion and is a future resource needed in various industries and scientific fields. However, it is not easy to enrich deuterium because the proportion of deuterium in the hydrogen mixture is scarce, at approximately 0.016 %. Furthermore, the physical and chemical properties of the hydrogen mixture and deuterium are very similar. Therefore, the efficient separation of deuterium from hydrogen mixtures is often a significant challenge when using modern separation technologies. Recently, to effectively separate deuterium, studies utilizing the 'Kinetic Quantum Sieving Effect (KQS)' of porous materials are increasing. Therefore, in this review, two different strategies have been discussed for improving KQS efficiency for hydrogen isotope separation performance using nanoporous materials. One is the gating effect, which precisely controls the aperture locally by adjusting the temperature and pressure. The second is the breathing phenomenon, utilizing the volume change of the structure from closed system to open system. It has been reported that efficient hydrogen isotope separation is possible using these two methods, and each of these effects is described in detail in this review. In addition, a specific-isotope responsive system (e.g., 2nd breathing effect in MIL-53) has recently been discovered and is described here as well.

• Bulletin of the Korean Chemical Society
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• v.29 no.9
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• pp.1769-1773
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• 2008

fThe kinetics and mechanism of the reactions of Y-O-aryl phenylphosphonochloridothioates with X-pyridines are investigated in acetonitrile at 35.0 ${^{\circ}C}$. The negative value of the cross-interaction constant, $\rho$XY = −0.46, indicates that the reaction proceeds by concerted $S_N2$ mechanism. The observed $k_H/k_D$ values involving d-5 pyridine ($C_5D_5N$) nucleophiles are greater than unity (1.05-1.11). The net primary deuterium kinetic isotope effects, $(k_H/k_D)_{net}$ = 1.28-1.35, excluding the increased $pK_a$ effect of d-5 pyridine are obtained. The transition state with a hydrogen bond between the leaving group Cl and the hydrogen (deuterium) atom in the C-H(D) is suggested for the studied reaction system.

• Analytical Science and Technology
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• v.35 no.5
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• pp.205-211
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• 2022

Deuterium (D) is an isotope with one more neutron number than hydrogen (H). Heavy elements rarely change their chemical properties with little effect even if the number of neutrons increases, but low-mass elements change their vibration energy, diffusion rate, and reaction rate because the effect cannot be ignored, which is called an isotope effect. Recently, in the semiconductor and display industries, there is a trend to replace hydrogen gas (H₂) with deuterium gas (D₂) in order to improve process stability and product quality by using the isotope effect. In addition, as the demand for D₂ in industries increases, domestic gas producers are making efforts to produce and supply D₂ on their own. In the case of high purity D₂, most of them are produced by electrolysis of heavy water (D₂O), and among D₂, hydrogen deuteride (HD) molecules are present as isotope impurities. Therefore, in order to maximize the isotope effect of hydrogen in the electronic industry, HD, which is an isotope impurity of D₂ used in the process, should be small amount. To this end, purity analysis of D₂ for industrial processing is essential. In this study, HD quantitative analysis of D₂ for high purity D₂ purity analysis was established and hydrogen isotope RM (Reference material) was developed. Since hydrogen isotopes are difficult to analyze with general gas analysis instrument, they were analyzed using a high-precision mass spectrometer (Gas/MS, Finnigan MAT271). High purity HD gas was injected into Gas/MS, sensitivity was determined by a signal according to pressure, and HD concentrations in two bottles of D₂ were quantified using the corresponding sensitivity. The amount fraction of HD in each D₂ was (4518 ± 275) μmol/mol, (2282 ± 144) μmol/mol. D₂, which quantifies HD amount using the developed quantitative analysis method, will be manufactured with hydrogen isotope RM and distributed for quality management and maintenance of electronic industries and gas producers in the future.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3811-3816
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• 2013

Nucleophilic substitution reactions of ethyl methyl (2), ethyl propyl (4) and diisopropyl (7) chlorothiophosphates with substituted anilines and deuterated anilines are investigated kinetically in acetonitrile at $55.0^{\circ}C$. A concerted mechanism is proposed based on the selectivity parameters. The deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) are secondary inverse ($k_H/k_D=0.66-0.99$) with 2, primary normal and secondary inverse ($k_H/k_D=0.78-1.19$) with 4, and primary normal ($k_H/k_D=1.06-1.21$) with 7. The primary normal and secondary inverse DKIEs are rationalized by frontside attack involving hydrogen bonded, four-center-type transition state, and backside attack involving in-line-type transition state, respectively. The anilinolyses of ten chlorothiophosphates are examined based on the reactivity, steric effect of the two ligands, thio effect, reaction mechanism, DKIE and activation parameter.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1403-1406
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• 2010

• Bulletin of the Korean Chemical Society
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• v.29 no.10
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• pp.2065-2068
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• 2008

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3274-3278
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• 2012

The kinetic studies on the reactions of phenyl N-phenyl phosphoramidochloridate (8) with substituted anilines ($XC_6H_4NH_2$) and deuterated anilines ($XC_6H_4ND_2$) have been carried out in acetonitrile at $60.0^{\circ}C$. The obtained deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) are huge secondary inverse ($k_H/k_D$ = 0.52-0.69). A concerted mechanism is proposed with a backside attack transition state (TS) on the basis of the secondary inverse DKIEs and the variation trends of the $k_H/k_D$ values with X. The degree of bond formation in the TS is really extensive taking into account the very small values of the DKIEs. The steric effects of the two ligands on the rates are extensively discussed for the aminolyses of the chlorophosphate-type substrates on the basis of the Taft equation.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4403-4407
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• 2011

The nucleophilic substitution reactions of dipropyl chlorothiophosphate (3) with substituted anilines ($XC_6H_4NH_2$) and deuterated anilines ($XC_6H_4ND_2$) are investigated kinetically in acetonitrile at $55.0^{\circ}C$. The obtained deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) are primary normal ($k_H/k_D$ = 1.11-1.35). A concerted mechanism involving predominant frontside nucleophilic attack is proposed on the basis of the primary normal DKIEs and selectivity parameters. Hydrogen bonded, four-center-type transition state is proposed. The steric effects of the two ligands on the anilinolysis rates of various substrates are discussed.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2769-2772
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• 2012

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3783-3786
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• 2011