Recebido em 26/4/11; aceito em 23/2/12; publicado na web em 25/6/12The stability of N-propylbutanimine (1) was investigated under different experimental conditions. The acid-catalyzed selfcondensation that produced the E-enimine (4) and Z-inimine (5) was studied by experimental analyses and theoretical calculations. Since the calculations for the energy of 5 indicated that it had a lower energy than 4, yet 4 was the principal product, the selfcondensation of 1 must be kinetically controlled.