Benzoic acid derivatives: Evaluation of thermochemical properties with complementary experimental and computational methods

Thermodynamic properties of isomeric iso-butoxybenzoic acids: Experimental and theoretical study

“…Having established a set of G3MP2 enthalpies H 298 for iso-butoxybenzoic acids (see Table S8) we are able now to calculate effects of mutual interactions of carboxyl-group with the iso-butoxy-group on the benzene ring in the ortho-, meta-, and para-position (see Table 5). Similar to our recent results for the isomeric methoxybenzoic acids [7], only strong destabilization was observed for the ortho isomer. Mutual interactions in the meta position seems to be negligible within a few kJmol -1 .…”

“…For this reason, it is important to consider consistency of our new data for iso-butoxybenzoic acids in the context of the available in the literature data for isomeric methoxybenzoic acids [7], as well as with the recent systematic study of 4-n-alkoxybenzoic acids [9]. In the latter paper the sublimation enthalpies were measured by the Knudsen effusion method and adjusted to the reference temperature 298.15 K by using the Domalski and Hearing procedure [30].…”

“…Comparison of the experimental and calculated by G3MP2 and GA gas-phase enthalpies of formation of alkoxybenzoic acids at T = 298.15 K (in kJ·mol -1 ) The disagreement between the theoretical and the experimental values observed for ortho-substituted benzenes have already been observed in our previous study of the enthalpy of formation of 2-methoxybenzoic acid [7], as well as for 1,2-difluorobenzene [34]. In the current work we also observe the disagreement for 2-iso-butoxybenzoic acid.…”

“…The experimental ortho interactions of the methoxy-and iso-butoxy substituent with the carboxyl (see Table 5 [33] and benzene [39] provides the increment H(H→OCH 3 ) = -153.6 kJmol -1 for substitution of an H atom by the methoxy-group in the benzene ring. Likewise, applying the same procedure for the benzoic acid and benzene yields the increment H(H→COOH) = -378.4 kJmol -1 [7]. Introduction of the methoxy and carboxyl substituents into the benzene ring produces three additional increments [7]: (ortho Table 6).…”

“…Likewise, applying the same procedure for the benzoic acid and benzene yields the increment H(H→COOH) = -378.4 kJmol -1 [7]. Introduction of the methoxy and carboxyl substituents into the benzene ring produces three additional increments [7]: (ortho Table 6). These pairwise interactions were calculated (e.g.…”