Thesis (Ph.D.)--Boston University / [delta]'-Pyrazolines were prepared in which one or more of the groups R, Rl, R2, R3 are alkyl or phenyl and the other groups are hydrogen. In addition, the molecule was modified by the use of four other activating groups in the place of the carboxyl group, i.e. -CN, -CONH2 , -COCH3, and -No2. The compounds were decomposed thermally and the kinetics of the decomposition was followed by measuring the volume of nitrogen evolved as a function of time. From the data obtained, the rate constants and energies of activation were calculated. The purpose of the investigation was to determine the effects upon the rate constants and energies of activation produced by the alteration of the molecule at the above-indicated positions. The pyrazolines were prepared by the addition of diazomethane to the appropriate olefin, or by the addition of the appropriate diazoalkane to ethyl methacrylate. [TRUNCATED]