1993 Volume 30 Issue 3 Pages 232-238
The coordination and complexation behavior of Zr-dibutylphosphate was investigated by 31P-NMR measurement, in order to clarify the mechanism of the previously reported phenomena that the precipitates once formed at low HDBP/Zr mole ratio of 2 in an organic solution disappears with increasing HDBP/Zr. As the results of 31P-NMR spectrum measurements, following two steps were identified. (1) Species having Zr : DBP=1:3 immediately reacts with free HDBP to form species having Zr: DBP=1:4 with increasing HDBP/Zr, (2) Under the presence of higher HDBP/Zr concentration, species having more DBPs than 4 to one Zr are observed. DBP- (or HDBP) ligands in these species bridge two Zr ions to form three-dimensional net-work structure and have an interaction with HDBP in the solvent. Consequently, the mechanism was elucidated for the re-dissolution of Zr-DBP precipitates with sufficient free HDBP producing highly viscous oilyliquid.
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