Photostability of hydroxyoxime extractants of metals 2. Photo-isomerization and photo-degradation of 2-hydroxy-5-methylbenzophenone (Z)-oxime

Photo-isomerization of fluvoxamine in aqueous solutions

“…The oxime isomerization can be induced by temperature, light, H + and OH − ions, and a solvent [25]. Examples of photo-isomerization of compounds, 2-hydroxy-5-methylbenzophenone (E)-and (Z)-oximes with the oxime moiety in their structures exposed to a full spectrum of UV light were reported [23,26]. During the irradiation, the (E)-and (Z)-isomers of individual compounds were converted to (Z)-and (E)-isomers, respectively.…”

Degradation of organothiophosphorous extractant Cyanex 301

“…Our studies indicated that hydroxyoximes extractant degraded under the exposure to light and the rate of photodegradation was influenced by temperature, the presence of water and sulphuric acid [15][16][17][18][19]. Similar tests were performed for hydrophobic esters and amides of pyridine-3-carboxylic acid and pyridine-3,5-dicarboxylic acid.…”

Photo‐degradation of hydrophobic esters of pyridinecarboxylic acids as copper extractants from chloride media and their copper complexes

“…When water and hydrochloric acid was added to the solution, the flow of gas formed bubbles which mixed the aqueous and hydrocarbon phases. Photo‐degradation was carried out in the same way as previous studies of other derivatives of pyridinecarboxylic acid,18 individual model hydroxyoximes, and commercial hydroxyoxime extractants 13–17…”

“…The resistance of the extractants to light is important during industrial operations when extraction and stripping are carried out with open mixers and settlers in countries where exposure to light is unavoidable. Previous studies indicated that hydroxyoxime extractants degraded on exposure to light and the rate of photo‐degradation was influenced by temperature, and the presence of water and sulfuric acid 13–17. The initial results of photo‐degradation of 2‐ethylhexylpyridine‐3‐carboxylate and N , N ′‐bis(2‐ethylhexyl)pyridine‐3,5‐dicarboxamide indicated that UV light degrades these compounds, though they are more stable than the hydroxyoxime extractants.…”