Professor Hanack began his first independent research work on organofluorine chemistry. At the same time he developed a great interest in special topics of stereochemistry, mostly in the field of conformational analysis. During this time he wrote one of the first books on conformation analysis, Conformation Theory (1969).
He very soon switched to physical organic chemistry, which remained his prime interest for the first half of his research period. He led a vigorous research team specializing in physical organic chemistry, which culminated in the first generation of 'vinyl cations' by the solvolysis of homoallenyl and homopropargyl systems (1964). The research on physical organic chemistry rewarded him with the discovery of super leaving groups, trifluoromethanesulfonates and nonafluoromethanesulfonates, for the generation of vinyl cations. Later on it was also possible for the first time to prove even the existence of an alkynyl cation. The first book on Vinyl Cations was published in 1979 together with P. Stang, Z. Rappoport and L. R. Subramanian (Academic Press). Simultaneously Professor Hanack pursued research on several other topics such as the synthesis and cycloaddition reactions of perfluoroalkylsulfones and the synthesis of fluorinated pyrethroids, an important class of insecticides.
Professor Hanack is a strong believer of new ideas and percepts and that scientific goals are best approached in a multidisciplinary way. From 1978