Photochemical oxidation of C-14-labelled oxalic acid by cerium(IV) sulfatein acidic solution

Citation
Ja. Van Den Berg et al., Photochemical oxidation of C-14-labelled oxalic acid by cerium(IV) sulfatein acidic solution, S AFR J C-S, 53(2), 2000, pp. 119-124
Citations number
13
Categorie Soggetti
Chemistry
Journal title
SOUTH AFRICAN JOURNAL OF CHEMISTRY-SUID-AFRIKAANSE TYDSKRIF VIR CHEMIE
ISSN journal
03794350 → ACNP
Volume
53
Issue
2
Year of publication
2000
Pages
119 - 124
Database
ISI
SICI code
0379-4350(200009)53:2<119:POOCOA>2.0.ZU;2-F
Abstract
The kinetic parameters for the reaction between C-14-labelled oxalic acid a nd Ce(IV) in a H2SO4 medium were determined in the presence and absence of ultraviolet radiation using a scintillation technique. The thermal reaction was also monitored by the stopped-flow spectrophotometric method. A new re action mechanism based on the behaviour of a photoactive sulfate hydrogen o xalato cerium(IV) ion as an intermediate species prior to the rate-determin ing oxidation step is suggested. The increase in activation energy with an increase in [H+] In the H2SO4 medium is explained in terms of the endotherm ic formation of this intermediate Ce(IV) complex ion.