Interaction reactions between 5-dodecylsalicylaldoxime and 5-nonylsalicylaldoxime, the active components of LIX 622 and LIX 622N, respectively, and I-tridecanol and isotridecanol-N in toluene at 301 K have been studied by vapour pressure osmometry. The osmometric results have been numerically treated and interpreted in terms of the formation of 1: 1 species for which the formation constants have been evaluated. Finally, the osmometric behaviour of commercial reagents containing the salicylaldoxime derivatives and isotridecanol-N has been also studied and interpreted on the basis of the model of interactions of their components previously derived. (c) 2007 Elsevier B.V. All rights reserved.