Journal Articles (before-1995)

Permanent URI for this collectionhttp://localhost:4000/handle/123456789/16938

Browse

Author: search.filters.author.Sherwood, J. N.Subject: search.filters.subject.Self-diffusion

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Self-diffusion and Conduction in Hydrogen-Bonded Solids: Part 1.—Labile Proton Diffusion in Pivalic Acid
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (4), 1972) Hood, G. M.; Lockhart, N. C.; Sherwood, J. N.
    A study has been made of the self-diffusion of labile protons in the plastic phase of pivalic acid using (CH3)3CCOO3H as the tracer. The carboxyl protons diffuse approximately 103 times more rapidly than the molecules and with a significantly different activation energy. Both differences arc confirmed by high-resolution n.m.r. measurements. Conductimctric measurements show that the proton migration is not accompanied by an equivalent charge transport. This leads to the conclusion that the proton migrates via an exchange mechanism which involves molecular rotation.
  • No Thumbnail Available
    Item
    Self-diffusion and Conduction in Hydrogen Bonded Solids: Part 2.—Self-diffusion of C6H514COOH and C6H5COO3H in Single Crystals of Benzoic Acid
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (3), 1972) McGhie, A. R.; Sherwood, J. N.
    A study has been made of the self-diffusion of the labelled species C6H514COOH and C6H5COO3H in single and polycrystallinc specimens of benzoic acid. The two tracers diffuse in a similar manner in the latter where grain-boundary diffusion may predominate. In the pure single crystals the tritium tracer diffuses more rapidly than the 14-carbon tracer and by a different mechanism. The 14-carbon labelled tracer diffuses with the characteristics of molecular vacancy self-diffusion. From a consideration of the effects of ambient conditions and the residual concentration of water in the samples, it is concluded that the rapid tritium diffusion process is extrinsic in nature and that it is a consequence of the exchange of the labile proton with included water coupled with the interstitial diffusion of the water molecule in the lattice.