Studies of the Chemistry of Systems Involving Water, Hydrogen Peroxide and Plutonium (IV) Nitrate in Tri-n-Butyl Phosphate

Author

Lawrence J. Mullins Jr.

Publication Date

5-28-1957

Abstract

The reaction of tri-n-butyl phosphate (TBP), with water and hydrogen peroxide is studied by means of distribution experiments. The solubility of water in TBP-hexane, at low TBP concentrations, is consistent with the premise that H₂O•TBP is the principal solvate species formed at low hydrogen peroxide concentrations. The distribution data at high hydrogen peroxide concentrations indicate that another species such as H₂O₂•TBP is also present. The reaction of hydrogen peroxide with plutonium(IV) nitrate in TBP is studied by a spectrophotometric method. A complex is formed which contains one plutonium atom and two peroxy-oxygen atoms. The formation of the complex can be represented by the following equation: Pu(NO₃)₄•2TBP + H₂O₂•2TBP ⇄ Pu(OO)(NO₃)₂•2TBP + 2(HNO₃•TBP)

If the concentrations are expressed in moles per liter, the equilibrium constant for this reaction at 25°C is 49.7 (±0.5) at a nitric acid concentration of 0.235 M. The precipitation of plutonium peroxide from TBP-hexane solution is demonstrated. The effect of water, nitric acid, and hydrogen peroxide concentrations on the solubility and crystal structure of plutonium peroxide precipitated from TBP solution is investigated. Both the solubility and crystal structure of the precipitate strongly depend on the water and nitric acid concentrations. The face-centered cubic structure of plutonium peroxide is favored by high water and low nitric acid concentrations. The hexagonal platelet structure of plutonium peroxide is favored by low water and high nitric acid concentrations. The data are consistent with the premise that the face-centered cubic structure is a polymeric structure in which (PuOPu)⁺⁶ groups are linked by peroxy-oxygen atoms.

Language

English

Document Type

Dissertation

Degree Name

Chemistry

Level of Degree

Doctoral

Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

John Francis Suttle

Second Committee Member

Jesse LeRoy Riebsomer

Third Committee Member

Robert A. Penneman

Fourth Committee Member

Milton Kahn

Fifth Committee Member

Ernest Lynne Martin

Sixth Committee Member

Thomas T. Castonguay

Recommended Citation

Mullins, Lawrence J. Jr.. "Studies of the Chemistry of Systems Involving Water, Hydrogen Peroxide and Plutonium (IV) Nitrate in Tri-n-Butyl Phosphate." (1957). https://digitalrepository.unm.edu/chem_etds/132