Equilibria of Several Reactions of Aromatic Amines

Thermochemistry of amines: experimental standard molar enthalpies of formation of some aliphatic and aromatic amines

“…The thermochemical properties of N,N-dimethylaniline have already been given by Pedley et al (7) from reaction calorimetry, D f H°m(l) = (33.5 2 6.3) kJ·mol −1 and from combustion calorimetry, (9) D f H°m(l) = (47.7 2 3.2) kJ·mol −1 {the value of the enthalpy of vaporization, (52.8 2 3.4) kJ·mol −1 , is also reported in this work (9) }. The significant discrepancy between the published results as well as the inaccuracy of the measured quantities for N,N-dimethylaniline encouraged our redetermination.…”

“…(6) This paper follows this course and is concerned with the investigation of branched aliphatic amines and some aromatic amines. The body of thermochemical data for amines is considerable, (7) but the data for branched and aromatic amines are still scarce, and sometimes doubtful, because some properties of key molecules of this row were measured with insufficient accuracy (for N-ethylaniline (8) and N,N-dimethylaniline (9) to about 274 kJ·mol −1 ) or even only assessed (10) (enthalpy of vaporization for tert-alkyl substituted amines). This paper reports thermochemical measurements (combustion calorimetry, transpiration, and d.s.c.)…”

Benchmark Thermochemistry of N-Methylaniline

“…There are also two estimates of Δ l g H m (298.15 K) of N-methylaniline available in the literature. 27,40 The value Δ l g H m (298.15 K) = 53.1 kJ•mol −1 (broadly used in the literature earlier) was estimated 40 by simple approximation of experimental vapor pressures from the static method 35 using the Clausius−Clapeyron equation. But it should be pointed out that we have revealed some inconsistency of the lower data points of this data set in chapter 3.2.…”

Synthesis of N,N-Dimethylaniline from Aniline and Methanol

“…Though the ratio of water is at a minimum in sulfuric acid, the maximum conversion of aniline to the products was not obtained, which is probably due to the weak secondary ionization of sulfuric acid. From the results it is evident that in the absence of acid the formation of methylaniline and dimethylaniline is not possible, although in an earlier publication by Vriens and Hill (1952) dealing with this reaction no mention of any catalyst was made, suggesting that the reaction can proceed in the absence of a catalyst. The present observations are nevertheless in conformity with the results reported earlier in the literature which indicate the need of a catalyst to achieve the reaction.…”

“…(1) and C6H5NH2(g) + 2CH3OH(g) ^C6H5N(CH3)2(g) + 2H20(g) (2) are available (Stull et al, 1969). The standard enthalpy and entropy changes of the above reactions are expected to be independent of temperature for the negligible ACP values (Vriens and Hill, 1952) and the equilibrium constants may be represented by the equation In K°p = -AH0 29$/RT + AS°2 qs/R…”