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Kinetics of the Thermal Decomposition of Dimethylmercury. II. Carbon‐13 Isotope Effect
dc.contributor.authorRussell, Morley E.en_US
dc.contributor.authorBernstein, Richard B.en_US
dc.date.accessioned2010-05-06T23:13:11Z
dc.date.available2010-05-06T23:13:11Z
dc.date.issued1959-03en_US
dc.identifier.citationRussell, Morley E.; Bernstein, Richard B. (1959). "Kinetics of the Thermal Decomposition of Dimethylmercury. II. Carbon‐13 Isotope Effect." The Journal of Chemical Physics 30(3): 613-617. <http://hdl.handle.net/2027.42/71109>en_US
dc.identifier.urihttps://hdl.handle.net/2027.42/71109
dc.description.abstractThe C13 kinetic isotope effect in the pyrolysis of gaseous dimethylmercury has been studied in the presence and absence of cyclopentane inhibitor from 290–375°C for the inhibited and 290–350°C for the uninhibited reactions. The isotopic fractionation factor (S) is defined as the ratio of rate constants for the decomposition of Hg(C12H3)2 vs C12H3HgC13H3. S shows a strong dependence upon the degree of inhibition of the methyl radical chain, which, in turn, is a function of the ratio of cyclopentane to dimethylmercury. S is also a function of the total pressure.The dependence of S upon the degree of inhibition agrees quantitatively with the predictions of the mechanism proposed in I. The pressure effect on the isotope effect is attributed to the unimolecular nature of the rate determining step (Hg☒C bond rupture) and is consistent with the over‐all kinetics.The isotope rate factor in the fully inhibited high‐pressure limit, α, is 1.034±0.002 (essentially independent of temperature over the range studied), compared to a value of 1.011±0.001 for the uninhibited (chain) decomposition.en_US
dc.format.extent3102 bytes
dc.format.extent355597 bytes
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dc.publisherThe American Institute of Physicsen_US
dc.rights© The American Institute of Physicsen_US
dc.titleKinetics of the Thermal Decomposition of Dimethylmercury. II. Carbon‐13 Isotope Effecten_US
dc.typeArticleen_US
dc.subject.hlbsecondlevelPhysicsen_US
dc.subject.hlbtoplevelScienceen_US
dc.description.peerreviewedPeer Revieweden_US
dc.contributor.affiliationumChemistry Department, University of Michigan, Ann Arbor, Michiganen_US
dc.description.bitstreamurlhttp://deepblue.lib.umich.edu/bitstream/2027.42/71109/2/JCPSA6-30-3-613-1.pdf
dc.identifier.doi10.1063/1.1730018en_US
dc.identifier.sourceThe Journal of Chemical Physicsen_US
dc.identifier.citedreferenceM. E. Russell and R. B. Bernstein, J. Chem. Phys. 30, 607 (1959), preceding paper.en_US
dc.identifier.citedreferenceSee A. Maccoll and P. J. Thomas, J. Chem. Phys. 23, 1722 (1955) and Friedman, Bernstein, and Gunning, J. Chem. Phys. 23, 109, 1722 (1955), for a somewhat similar situation in the ethyl bromide pyrolysis.en_US
dc.identifier.citedreferenceM. Dole, Chem. Revs. 51, 266 (1952); C. R. McKinney et al., Rev. Sci. Instr. 21, 724 (1950).en_US
dc.identifier.citedreferenceSee Friedman et al., 2.en_US
dc.identifier.citedreferenceIt was shown [Ph.D. dissertation of M. E. Russell, University of Michigan (1958) available from University Microfilms, Ann Arbor, Michigan] by the tracer technique that essentially none of the carbon in the methane product originated from the cyclopentane, with >98% derived from the DMM decomposed.en_US
dc.identifier.citedreferenceNot shown on the graph are a number of points at higher values of Q (with correspondingly smaller values of S°S°) for which the total pressure was not comparable with the rest of the series.en_US
dc.identifier.citedreferenceIt should be noted that the increase in the isotope effect upon addition of cyclopentane does not occur by virtue of the pressure effect alone; from Table II, the addition of a great excess of SF6SF6 to DMM caused no significant change in the (low) isotope effect of 1.1%.en_US
dc.identifier.citedreferenceThe symbols C and C∗C∗ represent C12C12 and C13,C13, respectively. In order to simplify (without loss of rigor), the original Steps 2 and 1 have been combined as the new Step 1; similarly for the original Steps 3 and 7, giving the new Step 3.en_US
dc.identifier.citedreferenceThe observed positive curvature of the S°S° vs Q curve (Fig. 1) is satisfactorily explained by the hyperbolic form of Eq. (6); however, no attempt at quantitative treatment of data at high Q is warranted in view of the oversimplified reaction mechanism assumed in the present treatment.en_US
dc.identifier.citedreferenceR. B. Bernstein, J. Phys. Chem. 56, 893 (1952); R. E. Weston, Jr., J. Chem. Phys. 26, 975 (1957).en_US
dc.identifier.citedreference(a) J. Bigeleisen, J. Phys. Chem. 56, 823 (1952); (b) J. Bigeleisen, J. Chem. Phys. 17, 675 (1949); (c) N. B. Slater, Proc. Roy. Soc. (London) A194, 112 (1948).en_US
dc.identifier.citedreferenceR. B. Bernstein, J. Chem. Phys. 22, 710 (1954).en_US
dc.identifier.citedreferenceH. S. Gutowsky, J. Chem. Phys. 17, 128 (1949).en_US
dc.identifier.citedreferenceJ. Bigeleisen and M. Wolfsberg, J. Chem. Phys. 21, 1972 (1953); 22, 1264 (1954).en_US
dc.owningcollnamePhysics, Department of


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