Isolation and characterisation of the LIX®63 degradation products 5,8-diethyl-6,7-dodecanedione monooxime (keto-oxime) and 5,8-diethyl-6,7-dodecanediol (diol) and regeneration of oxime from keto-oxime

The combination of LIX((R))63 and Versatic 10 possesses desirable metal separation properties, but does result in some degradation of LIX((R))3 oxime. In the present work, a major LIX((R))63 degradation product known to form under extract operating conditions was synthesised, purified and spectroscopically characterised as 5,8-diethyl-6,7-dodecanedione monooxime (keto-oxime). Borohydride-based regeneration of LIX((R))63 oxime from keto-oxime has been demonstrated. A procedure to overcome complications associated with oxime regeneration in the presence of Versatic 10 has been suggested. Another potential LIX((R))63 degradation product, 5,8-diethyl-6,7-dodecanediol (diol) was also synthesised and spectroscopically characterised. Borohydride-based regeneration of LIX((R))63 oxime from keto-oxime would result in the generation of diol from reduction of any associated diketone and acyloin impurities. Crown Copyright (c) 2007 Published by Elsevier B.V. All rights reserved.