Organic constituents of cruds in Cu solvent extraction circuits.: II. Photochemical and acid hydrolytic reactions of alkaryl hydroxyoxime reagents

Two reagents—5-dodecylsalicylaldoxime (DSAO) and 2-hydroxy-5-nonyl-acetophenone oxime (HNAPO)—used in the commercial solvent extraction of copper ions from ore-leach solutions were subjected to UV photolysis. The products were examined by thin layer chromatograph (TLC) and UV-visible and infrared (IR) spectroscopy for comparison with compounds previously identified in interfacial `crud' found in copper solvent extraction. Similar analyses were made for products of the reaction of the same reagents with concentrated sulfuric acid. Photolysis with a UV lamp gave complete degradation of the reagents within 12 h. Copper complexes of the reagents were virtually unchanged after 30 h exposure to the UV lamp. Products included polymers which retained carbonyl functions, but not the hydroxyl function. Additional oily and crystalline products precipitated from the heptane solutions; these low solubility products exhibited aliphatic carboxylic acid functions, similar to the unidentified polar compounds found in `crud'. TLC analyses of the photolysis solutions on silica gel gave large immobile fractions, which was also similar to some `crud' organics. Photolysis products were responsible for marked decreases in the interfacial tensions between heptane solutions of the reagents and water. Products from reaction of the reagents with concentrated sulfuric acid had also lost the hydroxyl function. These products were also immobile in TLC analysis. Neither the photolysis nor the acid hydrolysis reactions gave the expected benzisoxazoles or benzoxazoles as major products.