Nitro-substituted benzoxazoles having utility as metallurgical extractants

摘要

Nitro-substituted 2-(2-hydroxyphenyl)benzoxazoles of the formula wherein one of R3 and R4 is -NO2 and the other is -H, -NO2 or alkyl of 1 to 20 carbons and R1 and R2 independently are -H or alkyl of 1 to 20 carbons, with the proviso that R1, R2, R3 and R4 contain a total of at least 7 carbons, are acidic, oil soluble compounds having utility for extraction of copper from strongly acidic ore leaches. Excellent selectivity for copper over iron is exhibited by the subject compounds.