| Popis: |
Constant-current coulometry has been applied to the titration of barbituric acid derivatives, i.e., sodium phenobarbital, sodium, seconal, sodium barbital, and sodium sandoptal. The titrant is generated mercury (II). The titration may be performed in aqueous potassium nitrate-acetone, or aqueous sodium perchlorateacetone solutions. The most sensitive systems are the partially nonaqueous ones, with both supporting electrolytes giving similar results. Comparable results also were obtained at room temperature and at 37°. Considerable evidence has been obtained to support the theory that mercury(II) is not generated directly in these media, but is formed from the disproportionation of mercury (I) into the element and mercury(II). Qualitative tests proved the presence of all three species in the titration medium. Structural analysis of the compound formed in the coulometry cell was performed, and with sodium phenobarbital the evidence indicates that a polymeric compound containing continuous Hg-N linkages is formed. The evidence for the other compounds is less conclusive, probably because a mixture of products is formed in the titration cell. |
