Hans Nilsson

Sorption of trivalent plutonium onto UO2 and the effect of the solid phase on the Pu oxidation state

Summary A problem with plutonium in sorption studies is its tendency to occur in a mix of oxidation states. This work was a study of the sorption of plutonium on the solid phase UO2 — in a perchlorate medium as a function of pH — where plutonium is kept in its trivalent oxidation state. Experiments also showed that uranium(IV) oxide can reduce Pu(IV) to Pu(III) in an acidic solution and maintain it in that state. It was observed at the same time that the chemically inert solid phases TiO2 and ThO2 possibly increase the rate of disproportionation of Pu(IV) at a pH of about 0.5. In accordance with previous studies MnO2 was found to have an oxidizing effect, converting Pu(IV) into Pu(VI). A comparison is made between the sorption of Th(IV), Pu(III) and Co(II) on UO2 and TiO2, and Pu(VI) on TiO2.

A Synthesis of Optically Active 3-Benzyladipic Acid and Assignment of its Absolute Configuration

Abstract Derivatives of 3-benzyladipic acid are important starting materials for the synthesis of tetracyclines. They are used to construct the D, C, and part of the B rings in one synthetic scheme employed by the Pfizer group,1 who have developed several methods for the synthesis of 5 with the object of permitting the introduction of a variety of substituents in the aromatic D-ring and also at C-6. Apparently only racemic 3-benzyladipic acids were prepared and used by them.

Sorption of Pu(III-IV) onto TiO2: A Preliminary Study

A preliminary study of the sorption of reduced plutonium (III-IV) onto TiO2 has been done under anoxic conditions at varying pH and ionic strength. The first approach was to study tetravalent Pu, but the sorption decreases with time in this case. This is probably due to disproportionation of Pu(IV) at the TiO2 surface, which then acts as a catalyst. A further observation that supports this explanation is that the sorption of Pu(IV) onto the walls of the experimental equipment is in some cases higher than the sorption of (disproportioned) Pu onto the oxide. Pu(III) sorption onto the oxide was also investigated and showed similarities with the previously investigated sorption of Pm(III) in a similar system.