The hydrolysis of hydroxamic acid complexants in the presence of non-oxidizing metal ions 1: Ferric ions.

Andrieux, Fabrice Pierre Louis and Boxall, C. and Taylor, R. J. (2007) The hydrolysis of hydroxamic acid complexants in the presence of non-oxidizing metal ions 1: Ferric ions. Journal of Solution Chemistry, 36 (10). pp. 1201-1217. ISSN 0095-9782

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Abstract

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.

Item Type: Journal Article
Journal or Publication Title: Journal of Solution Chemistry
Additional Information: The original publication is available at www.springerlink.com
Uncontrolled Keywords: /dk/atira/pure/researchoutput/libraryofcongress/ta
Subjects:
Departments: Faculty of Science and Technology > Engineering
ID Code: 26511
Deposited By: Dr Fabrice PL Andrieux
Deposited On: 27 May 2009 09:23
Refereed?: Yes
Published?: Published
Last Modified: 16 Sep 2019 00:25
URI: https://eprints.lancs.ac.uk/id/eprint/26511

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