Actinide complexation kinetics: rate and mechanism of dioxoneptunium (V) reaction with chlorophosphonazo III
Abstract
Rates of complex formation and dissociation in NpO{sub 2}{sup +}- Chlorophosphonazo III (2,7-bis(4-chloro-2-phosphonobenzeneazo)-1,8- dihydroxynapthalene-3,6-disulfonic acid)(CLIII) were investigated by stopped-flow spectrophotometry. Also, limited studies were made of the rates of reaction of La{sup 3+}, Eu{sup 3+}, Dy{sup 3+}, and Fe{sup 3+} with CLIII. Rate determining step in each system is an intramolecular process, the NpO{sub 2}{sup +}-CLIII reaction proceeding by a first order approach to equilibrium in the acid range from 0.1 to 1.0 M. Complex formation occurs independent of acidity, while both acid dependent and independent dissociation pathways are observed. Activation parameters for the complex formation reaction are {Delta}H=46.2{+-}0.3 kJ/m and {Delta}S=7{+-} J/mK (I=1.0 M); these for the acid dependent and independent dissociation pathways are {Delta}H=38.8{+-}0.6 kJ/m, {Delta}S=-96{+-}18 J/mK, {Delta}H=70.0{+-} kJ/m, and {Delta}S=17{+-}1 J/mK, respectively. An isokinetic relationship is observed between the activation parameters for CLIII complex formation with NpO{sub 2}{sup +}, UO{sub 2}{sup 2+}, Th{sup 4+}, and Zr{sup 4+}. Rates of CLIII complex formation reactions for Fe{sup 3+}, Zr{sup 4+}, NpO{sub 2}{sup +}, UO{sub 2}{sup 2+}, Th{sup 4+}, La{sup 3+}, Eu{sup 3+}, and Dy{sup 3+} correlate with cation radius rather than charge/radius ratio.
- Authors:
- Publication Date:
- Research Org.:
- Argonne National Lab., IL (United States)
- Sponsoring Org.:
- USDOE Office of Energy Research, Washington, DC (United States)
- OSTI Identifier:
- 436450
- Report Number(s):
- ANL/CHM/PP-87026
ON: DE97002721; TRN: 97:004395
- DOE Contract Number:
- W-31-109-ENG-38
- Resource Type:
- Technical Report
- Resource Relation:
- Other Information: PBD: Dec 1996
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 40 CHEMISTRY; NEPTUNYL COMPLEXES; NEPTUNIUM COMPLEXES; URANYL COMPLEXES; IRON COMPLEXES; ZIRCONIUM COMPLEXES; THORIUM COMPLEXES; LANTHANUM COMPLEXES; EUROPIUM COMPLEXES; DYSPROSIUM COMPLEXES; LIGANDS
Citation Formats
Fugate, G., Feil-Jenkins, J.F., Sullivan, J.C., and Nash, K.L. Actinide complexation kinetics: rate and mechanism of dioxoneptunium (V) reaction with chlorophosphonazo III. United States: N. p., 1996.
Web. doi:10.2172/436450.
Fugate, G., Feil-Jenkins, J.F., Sullivan, J.C., & Nash, K.L. Actinide complexation kinetics: rate and mechanism of dioxoneptunium (V) reaction with chlorophosphonazo III. United States. doi:10.2172/436450.
Fugate, G., Feil-Jenkins, J.F., Sullivan, J.C., and Nash, K.L. Sun .
"Actinide complexation kinetics: rate and mechanism of dioxoneptunium (V) reaction with chlorophosphonazo III". United States.
doi:10.2172/436450. https://www.osti.gov/servlets/purl/436450.
@article{osti_436450,
title = {Actinide complexation kinetics: rate and mechanism of dioxoneptunium (V) reaction with chlorophosphonazo III},
author = {Fugate, G. and Feil-Jenkins, J.F. and Sullivan, J.C. and Nash, K.L.},
abstractNote = {Rates of complex formation and dissociation in NpO{sub 2}{sup +}- Chlorophosphonazo III (2,7-bis(4-chloro-2-phosphonobenzeneazo)-1,8- dihydroxynapthalene-3,6-disulfonic acid)(CLIII) were investigated by stopped-flow spectrophotometry. Also, limited studies were made of the rates of reaction of La{sup 3+}, Eu{sup 3+}, Dy{sup 3+}, and Fe{sup 3+} with CLIII. Rate determining step in each system is an intramolecular process, the NpO{sub 2}{sup +}-CLIII reaction proceeding by a first order approach to equilibrium in the acid range from 0.1 to 1.0 M. Complex formation occurs independent of acidity, while both acid dependent and independent dissociation pathways are observed. Activation parameters for the complex formation reaction are {Delta}H=46.2{+-}0.3 kJ/m and {Delta}S=7{+-} J/mK (I=1.0 M); these for the acid dependent and independent dissociation pathways are {Delta}H=38.8{+-}0.6 kJ/m, {Delta}S=-96{+-}18 J/mK, {Delta}H=70.0{+-} kJ/m, and {Delta}S=17{+-}1 J/mK, respectively. An isokinetic relationship is observed between the activation parameters for CLIII complex formation with NpO{sub 2}{sup +}, UO{sub 2}{sup 2+}, Th{sup 4+}, and Zr{sup 4+}. Rates of CLIII complex formation reactions for Fe{sup 3+}, Zr{sup 4+}, NpO{sub 2}{sup +}, UO{sub 2}{sup 2+}, Th{sup 4+}, La{sup 3+}, Eu{sup 3+}, and Dy{sup 3+} correlate with cation radius rather than charge/radius ratio.},
doi = {10.2172/436450},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Dec 01 00:00:00 EST 1996},
month = {Sun Dec 01 00:00:00 EST 1996}
}
-
A kinetic study of the complexation reaction between the dioxouranium(VI) ion and Arsenazo III
The rates of formation of the 1:1 complexes between the aquo UO/sub 2//sup 2 +/ ion and Arsenazo III were determined in 2.0 M perchloric acid solutions. The kinetic data are consistent with a first-order approach to equilibrium due to the concentration conditions under which the reaction was studied. 14 refs., 2 tabs.