| Popis: |
The combustion energies of the neutral methyl esters of 1,3-benzenedicarboxylic, 1,4-benzenedicarboxylic, 1,3,5-benzenetricarboxylic, 1,2,4,5-benzenetetracarboxylic, benzenepentacarboxylic, and benzenehexacarboxylic acids have been determined using a static bomb calorimeter. The enthalpies of formation in the crystalline state at 298.15 K have been derived for these six esters. The results are: Neutral methyl ester of the acid −ΔH f o (c) kcal th mol −1 1,3-Benzenedicarboxylic 174.7 ± 0.2 1,4-Benzenedicarboxylic 175.1 ± 0.2 1,3,5-Benzenetricarboxylic 263.2 ± 0.3 1,2,4,5-Benzenetetracarboxylic 342.3 ± 0.3 Benzenepentacarboxylic 427.4 ± 0.4 Benzenehexacarboxylic 504.5 ± 0.5 The results are discussed in terms of the steric effects introduced by carbomethoxy groups substitution in the benzene nucleus. |
