16009-94-2Relevant academic research and scientific papers
Transformations of structural defects in heated model clay precursors by ESR spectroscopy
Horvath, L.,Noethig-Laslo, V.,Bilinski, H.,Foerster, H.
, p. 1061 - 1066 (1990)
In this paper we discuss the broad ESR spectrum at g = 2, which we have observed in model clay compounds exposed to different conditions: (a) aged in the solid form in a closed test tube; (b) heated in an oven in the presence of oxygen; and (c) evacuated
Process for the preparation of oxalic acid and sodium hydrogen oxalate from crude sodium oxalate
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, (2008/06/13)
A process for producing oxalic acid, sodium oxalate or mixtures thereof comprises treating crude sodium oxalate solids or slurry, such as produced by the Bayer process in treating bauxite. The crude sodium oxalate solids or slurry include at least aluminum metal ions as well as other metal ions common to the Bayer process. The removal process comprises: dissolving the crude sodium oxalate in an aqueous solution to form a solution of sodium oxalate; separating insolubles from the solution; passing the solution through an ion exchange column to convert sodium oxalate, the ion exchange column having a bed of cation exchange resin of the acidic type, the solution as it passes over the bed of resin exchanging sodium ions of the sodium oxalate with hydrogen ions of the resin to produce sodium hydrogen oxalate acid, oxalic acid or mixtures thereof depending upon the strength of acidity of the resin, the exchanged sodium ions and the Al metal ions remaining on the bed of resin; and recovering the sodium hydrogen oxalate, oxalic acid or mixtures thereof as the effluent solution from the ion exchange column.
A NUCLEAR MAGNETIC RESONANCE STUDY OF THE MOBILITY OF WATER MOLECULES IN NaHC2O4*H2O
Larsson, K.,Tegenfeldt, J.
, p. 315 - 322 (2007/10/02)
Diffusive dynamical properties of the water molecule in the compound NaHC2O4*H2O have been investigated by 1H NMR, measuring the spin-lattice relaxation time in the rotating frame (T1ρ).A polycrystalline sample was used for measuring this relaxation time as a function of temperature, and a single crystal for measuring orientational dependence.One dynamical process has been found to be responsible for the relaxation: a 180 deg flip motion of H2O about its quasi twofold axis.The activation energy and the pre-exponential factor of the Arrhenius' relation for the correlation time of this motion are 62 kJ mol-1 and 3.5x10-16 s, respectively.Structural influence on the activation energy of the water flip motion is also discussed for five different solid hydrates.
