Abstract: The method of fuzzy mathematies is used in elustering N,N'-disubstituted amides RCON(R')R" in terms of their behaviour in extraction of U(Ⅵ),Pu(Ⅳ)and HNO₃. The fuzzy clustering results indicate that the extraetion behaviour of N,N'-disubstituted amides are determined by the substitutents R,R' and R"in amides,among these the role of R is more important.The study shows the feasibility of applying the fuzzy mathematies method to study the relationship between the structure and extraction behaviour of the extraetants.

Key words: amide, extraction, fuzzy cluster analysis, uranium, plutonium