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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - The hydrolysis of hydroxamic acid complexants in the presence of non-oxidizing metal ions 1: Ferric ions.
AU - Andrieux, Fabrice Pierre Louis
AU - Boxall, C.
AU - Taylor, R. J.
N1 - The original publication is available at www.springerlink.com
PY - 2007/10
Y1 - 2007/10
N2 - Hydroxamic acids (XHAs) are organic compounds with affinities for cations such as Fe3+, Np4+ and Pu4+ and have been identified as useful reagents in nuclear fuel reprocessing. Acid catalyzed hydrolysis of free XHAs is well known and may impact negatively on reprocessing applications. The hydrolysis of metal-bound XHAs within metal ion-XHA complexes is less understood. With the aid of speciation diagrams, we have modelled UV-visible spectrophotometric kinetic studies of the acid-catalyzed hydrolysis of acetohydroxamic acid (AHA) bound to the model ion Fe(III). These studies have yielded the following information for the hydrolysis of AHA in the Fe(AHA)2+ complex at 293 K: (i) the order with respect to [H+] during the rate determining step, m=0.97, is the same as for the free ligand, indicating a similarity of mechanisms; and (ii) the kinetic rate parameter, k 1=1.02×10−4 dm3⋅mol−1⋅s−1, is greater than that for the free ligand, k 0=1.84×10−5 dm3⋅mol−1⋅s−1 for pH>−0.5, a result that is consistent with a Hammett analysis of the system.
AB - Hydroxamic acids (XHAs) are organic compounds with affinities for cations such as Fe3+, Np4+ and Pu4+ and have been identified as useful reagents in nuclear fuel reprocessing. Acid catalyzed hydrolysis of free XHAs is well known and may impact negatively on reprocessing applications. The hydrolysis of metal-bound XHAs within metal ion-XHA complexes is less understood. With the aid of speciation diagrams, we have modelled UV-visible spectrophotometric kinetic studies of the acid-catalyzed hydrolysis of acetohydroxamic acid (AHA) bound to the model ion Fe(III). These studies have yielded the following information for the hydrolysis of AHA in the Fe(AHA)2+ complex at 293 K: (i) the order with respect to [H+] during the rate determining step, m=0.97, is the same as for the free ligand, indicating a similarity of mechanisms; and (ii) the kinetic rate parameter, k 1=1.02×10−4 dm3⋅mol−1⋅s−1, is greater than that for the free ligand, k 0=1.84×10−5 dm3⋅mol−1⋅s−1 for pH>−0.5, a result that is consistent with a Hammett analysis of the system.
KW - acetohydroxamic acid
KW - ferric ions
KW - complexation
KW - speciation
KW - hydrolysis
KW - kinetics
KW - NUCLEAR-FUEL
KW - BENZOHYDROXAMIC ACID
KW - ORGANIC EXTRACTANTS
KW - IRRADIATED FUELS
KW - HYDROXYLAMINE
KW - SEPARATION
KW - REDUCTION
KW - BEHAVIOUR
KW - KINETICS
KW - POWER
U2 - 10.1007/s10953-007-9183-9
DO - 10.1007/s10953-007-9183-9
M3 - Journal article
VL - 36
SP - 1201
EP - 1217
JO - Journal of Solution Chemistry
JF - Journal of Solution Chemistry
SN - 0095-9782
IS - 10
ER -