The reactions of anilines with 4-methylphenyl and 4-chlorophenyl 2,4-dinitrophenyl carbonates (MPDNPC and C1PDNPC, respectively) and the latter substrate with secondary alicyclic (SA) amines are subjected to a kinetic study in 44 wt % ethanol-water solution, at 25.0 °C, and an ionic strength of 0.2 M (KCl). The reactions are studied by following spectrophotometrically (360 nm) the release of 2,4-dinitrophenoxide anion. Under amine excess, pseudo-first-order rate coefficients (k[sub obsd]) are found. Plots of k[sub obsd] vs [amine] are linear and pH-independent, with slope k[sub N]. The Brønsted-type plots (log k[sub N] vs pK[sub a] of aminium ions) are linear, with slopes β = 0.68 and 0.66 for the reactions of anilines with MPDNPC and ClPDNPC, respectively, and β = 0.44 for the reactions of SA amines with ClPDNPC. The magnitude of the slope for the latter reaction indicates that its mechanism is concerted. The slope values for the reactions of anilines are in the borderline between stepwise and concerted mechanisms. The sensitivity of logk[sub N] to the basicity of the nonleaving group (β[sub nlg]) is ca. -0.7 for the reactions of anilines, in agreement with that found for the SA reactions (β[sub nlg] ca. -0.6). These results suggest that the reactions of anilines are concerted, although it is also possible that both mechanisms (stepwise and concerted) operate simultaneously. By comparison of the reactions under investigation between them and with similar aminolyses, the following conclusions can be drawn: (i) ClPDNPC is more reactive than MPDNPC toward the two amine series. (ii) The change of water to aqueous ethanol destabilizes a zwitterionic tetrahedral intermediate. (iii) The change of the nonleaving group from MeO to 4-methylphenoxy or 4-chlorophenoxy also destabilizes this intermediate. [ABSTRACT FROM AUTHOR]