Photostability of hydrophobic amides of pyridinecarboxylic acid as copper extractants from chloride media

The photostability of N-alkyl and N,N-dialkylpyridine-3-carboxamide, and N-alkyl and N,N-dialkylpyridine-2-carboxamide, and their copper complexes were studied. The obtained results indicated the influence of light (UV and vis) on the stability of pyridinecarboxamides. The degree of photodegradation depended on the type of solvent, the presence of water, hydrochloric acid or air in the solution. Also, the structure of compounds (the number and position of the amides group, structure of the amides carbon chain) influenced amides photostability. Products of photofragmentation of amides groups and photosubstitution at the pyridine ring were identified. Influence of ions of copper(II) and chloride during the photodegradation of copper complexes with pyridinecarboxamide was analyzed.