Isotope effects in the diffusion of carbon-12- and carbon-14-substituted molecules in the liquid phase

1969 ◽  
Vol 73 (1) ◽  
pp. 269-270 ◽  
Author(s):  
L. B. Eppstein
Keyword(s):  
Liquid Phase ◽  
Isotope Effects ◽  
Carbon 14

Carbon-14 isotope effects in the 1,3-dipolar addition of N,.alpha.-diphenylnitrone and styrene. Concerted cyclic process

1973 ◽  
Vol 95 (18) ◽  
pp. 6145-6146 ◽  
Author(s):  
Ben M. Benjamin ◽  
Clair J. Collins
Keyword(s):  
Isotope Effects ◽  
Cyclic Process ◽  
Carbon 14

Carbon-14 isotope effects in the formolysis and trifluoroacetolysis of 2-aryl-(aryl-14C)-ethyl p-nitrobenzenesulfonates

1971 ◽  
Vol 12 (13) ◽  
pp. 847-850 ◽  
Author(s):  
Yasuhide Yukawa ◽  
Takashi Ando ◽  
Mitsuru Kawada ◽  
Katsuo Token ◽  
Seung-Geon Kim
Keyword(s):  
Isotope Effects ◽  
Carbon 14

Carbon-14 and deuterium isotope effects in the borderline solvolysis of isopropyl .beta.-naphthalenesulfonate

1982 ◽  
Vol 104 (20) ◽  
pp. 5493-5494 ◽  
Author(s):  
Takashi Ando ◽  
Hiroshi Yamataka ◽  
Shinichi Tamura ◽  
Terukiyo Hanafusa
Keyword(s):  
Isotope Effects ◽  
Carbon 14 ◽  
Deuterium Isotope Effects

Deuterium isotope effects in liquid-liquid phase diagrams: Water + phenol and water + 2-methylpropanoic acid systems

1983 ◽  
Vol 36 (2) ◽  
pp. 215 ◽  
Author(s):  
DV Fenby ◽  
JR Khurma ◽  
ZS Kooner ◽  
RF Smith
Keyword(s):  
Liquid Phase ◽  
Phase Diagrams ◽  
Isotope Effects ◽  
Dispersion Interactions ◽  
Exchange Reactions ◽  
Molar Excess ◽  
Deuterium Isotope Effects ◽  
London Dispersion ◽  
Molar Excess Volumes ◽  
System Water

Phase-separation temperatures Tp have been measured for the systems H2O+C6H5OH, H2O+ C6H5OD, H20+ CsD5OD, D20+ C6H50H, D2O+ C6H5OD, D2O+ C6DsOD, H2O+ (CH3)2CHCO2H and D2O+ (CH3)2CHCO2H. For water+ 2-methylpropanoic acid, the differences in the Tp-x curves for the exchange and no-exchange systems are striking. For water + phenol, on the other hand, the effect of deuterium-exchange reactions on the Tp-x curves is very small. The results for all systems are in accord with the qualitative predictions of the Rabinovich theory, which accounts for deuterium isotope effects in liquid-liquid phase diagrams in terms of hydrogen bond and London dispersion interactions. Molar excess enthalpies and molar excess volumes at 300.15 K are reported for the system water + 2-methylpropanoic acid. The results are compared with those for water + acetic acid.

Carbon-14 and deuterium isotope effects during the [2 + 2] cycloaddition of diphenylketene to styrene

1978 ◽  
Vol 100 (8) ◽  
pp. 2570-2571 ◽  
Author(s):  
Clair J. Collins ◽  
Ben M. Benjamin ◽  
George W. Kabalka
Keyword(s):  
Isotope Effects ◽  
Carbon 14 ◽  
Deuterium Isotope Effects

Carbon-14 and tritium isotope effects in Hofmann degradation of quaternary amines

1964 ◽  
Vol 8 (3-4) ◽  
pp. 379-384 ◽  
Author(s):  
H. Simon ◽  
G. Müllhofer
Keyword(s):  
Isotope Effects ◽  
Carbon 14

Triple isotope effects accompanying evaporation of water: new insights from laboratory experiments

2020 ◽  
Author(s):  
Anna Pierchala ◽  
Kazimierz Rozanski ◽  
Marek Dulinski ◽  
Zbigniew Gorczyca ◽  
Robert Czub
Keyword(s):  
Surface Water ◽  
Liquid Phase ◽  
Laboratory Experiments ◽  
Isotope Effects ◽  
Water Bodies ◽  
Fractionation Factor ◽  
Preparation Methods ◽  
Mass Spectrom ◽  
Health Studies ◽  
Surface Water Bodies

<p>Stable isotopes of hydrogen and oxygen (<sup>2</sup>H and <sup>18</sup>O) are often used for quantification of water budgets of lakes and other surface water bodies, in particular for the assessment of underground components of those budgets [1]. Recent advances in laser spectroscopy enabled simultaneous analyses of <sup>2</sup>H, <sup>18</sup>O and <sup>17</sup>O content in water, with measurement uncertainties comparable (δ<sup>18</sup>O) or surpassing (δ<sup>2</sup>H) those routinely achieved by off-line sample preparation methods combined with conventional IRMS technique [2]. This open up the doors for improving reliability of isotope-aided budgets of surface water bodies by adding third isotope tracer (<sup>17</sup>O). This, however, requires adequate information on triple isotope effects accompanying evaporation of water, in particular the kinetic isotope effect related to evaporation of <sup>1</sup>H<sub>2</sub><sup>17</sup>O isotopologue.</p><p>Here we present the results of dedicated laboratory experiments aimed at quantification of triple isotope effects accompanying evaporation of water under fully developed diffusive sublayer [3]. Identical containers with predefined mass of water of known isotopic composition were placed in an isolated chamber with controlled atmosphere during the experiment (temperature, relative humidity). The chamber was flushed with synthetic air. At regular time intervals (approximately one week) containers were removed one by one from the chamber, the remaining mass of water in the removed container was determined gravimetrically, and stored for subsequent isotope analyses. The flow rate was adjusted at each step of the process to keep humidity inside the chamber constant. Evaporation continued until approximately half of the initial mass of water was removed from the containers. The experiment was repeated under diiferent conditions inside the chamber (two different temperatures and three different values of relative humidty).</p><p>The results of the experiments were interpreted in the framework of Craig-Gordon model of evaporation [3]. It turned out that the assumption often used in the description of isotopic effects accompanying evaporation that liquid phase is isotopically homogeneous during the process, leads to conflicting results for three isotope systems in use. However, if surface enrichment of the liquid phase, different for each heavy isotopologue (<sup>1</sup>H<sup>2</sup>H<sup>16</sup>O, <sup>1</sup>H<sub>2</sub><sup>18</sup>O, <sup>1</sup>H<sub>2</sub><sup>17</sup>O) is included in the model, consistent results for all three isotopes can be achieved, with calculated kinetic fractionation factor for <sup>1</sup>H<sub>2</sub><sup>17</sup>O isotopologue equal 14.76 ± 0.48 ‰,. This value agrees, within the quoted uncertainty, with the value of 14.60 ± 0.30 ‰ obtained by Barkan and Luz [4].  </p><p>Acknowledgements: The presented work was supported by National Science Centre (research grant No. 2016/23/B/ST10/00909) and by the Ministry of Science and Higher Education (project no. 16.16.220.842 B02)</p><p>References:<br>[1]   Rozanski K. Froehlich K. Mook WG. Technical Documents in Hydrology, No. 39, Vol. III, UNESCO, Paris, 2001 117 pp.<br>[2]   Pierchala A, Rozanski K, Dulinski M, Gorczyca Z, Marzec M, Czub R, Isotopes in Environmental and Health Studies, 2019 (55) 290-307.<br>[3]   Horita, J. Rozanski K. Cohen S. 2007. Isotopes in Environmental and Health Studies, 2007 (44) 23-49.<br>[4]   Barkan E. Luz B. Rapid Commun. Mass Spectrom., 2007(21) 2999-3005.</p>

Carbon-14 Isotope Effects in the Beckmann Rearrangement1a

1966 ◽  
Vol 31 (6) ◽  
pp. 1987-1988 ◽  
Author(s):  
I. T. Glover ◽  
V. F. Raaen
Keyword(s):  
Isotope Effects ◽  
Carbon 14
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