C. Turrión

Vapour pressures and enthalpies of sublimation of naphthalene and benzoic acid

Abstract Vapour pressures of crystalline naphthalene and benzoic acid, at temperatures near ambient, have been determined using an improved Knudsen effusion technique. From the experimental results the following values have been derived for the enthalpies of sublimation: naphthalene(c): ΔH s (298.15 K) = (72.8 ± 0.3) kJ · mol −1 ; benzoic acid(c): ΔH s (298.15 K) = (90.6 ± 0.2) kJ · mol −1 . Experimental results are compared with literature values.

Thermochemical properties of N-heterocyclic compounds I. Enthalpies of combustion, vapour pressures and enthalpies of sublimation, and enthalpies of formation of pyrazole, imidazole, indazole, and benzimidazole

Abstract The energies of combustion of pyrazole, imidazole, indazole, and benzimidazole have been determined using a static bomb calorimeter. The vapour pressures have been measured over a temperature range of about 20 K by the Knudsen-effusion technique. From the experimental results the following quantities for the four compounds at 298.15 K have been derived: Compound Δ f H m o (cr)/(kJ · mol −1 ) Δ sub H m o /(kJ · mol −1 ) Δ f H m o (g)/(kJ · mol −1 ) Pyrazole 105.4±0.7 74.0±0.4 179.4±0.8 Imidazole 49.8±0.6 83.1±0.2 132.9±0.6 Indazole 151.9±1.3 91.1±0.2 243.0±1.3 Benzimidazole 79.5±1.3 102.2±0.4 181.7±1.4

Thermochemical properties of N-heterocyclic compounds II. Enthalpies of combustion, vapour pressures, enthalpies of sublimation, and enthalpies of formation of 1,2,4-triazole and benzotriazole

Abstract The energies of combustion of 1,2,4-triazole and benzotriazole have been determined using a static bomb calorimeter. The vapour pressures have been measured over a temperature range of about 15 K by the Knudsen effusion technique. From the experimental results the following quantities for the two compounds at 298.15 K have been derived: Compound Δ f H m o (cr) Δ sub H m o Δ f H m o (g) kJ · mol −1 kJ · mol −1 kJ · mol −1 1,2,4-Triazole 108.7±0.4 84.0±0.7 192.7±0.8 Benzotriazole 236.5±1.2 99.0±0.5 335.5±1.3

Thermochemical properties of naphthalene compounds II. Enthalpies of combustion and formation of the 1- and 2-naphthols

Abstract The energies of combustion of 1-naphthoic and 2-naphthoic acids were determined using a static bomb calorimeter. The sublimation vapour pressures were measured in a given temperature range by the Knudsen effusion technique. The formation enthalpies in the crystalline state at 298.15 K and the sublimation enthalpies at the mean temperature of the measurement ranges were derived for the two acids. The values obtained are: −ΔH° f ( c ) kcal th mol −1 −ΔH s kcal th mol −1 1-naphthoic acid 79.71 ± 0.25 −26.38 ± 0.05 (at 350.5 K) 2-naphthoic acid 82.71 ± 0.35 −27.15 ± 0.19 (at 355.6 K) The results are discussed in terms of steric effects arising from the carboxylic group.

Thermochemical properties of N-heterocyclic compounds III. Enthalpies of combustion, vapour pressures and enthalpies of sublimation, and enthalpies of formation of 9H-carbazole, 9-methylcarbazole, and 9-ethylcarbazole

Abstract The energies of combusion of 9H-carbazole, 9-methylcarbazole, and 9-ethylcarbazole have been measured using a static bomb calorimeter. The vapour pressures have been determined over a temperature range of about 15 K by the Knudsen-effusion technique. From the experimental results the following quantities for the three compounds at 298.15 K have been derived: Δ f H m o (cr) Δ sub H m o Δ f H m o (g) Compound kJ · mol−1 kJ · mol−1 kJ · mol1 9H-Carbazole 101.7±2.8 103.3±1.1 205.0±3.0 9-Methylcarbazole 103.7±2.4 95.5±0.3 199.2±2.4 9-Ethylcarbazole 70.6±2.6 99.1±0.3 169.7±2.6

Structural effects on the thermochemical properties of carbonyl compounds I. Enthalpies of combustion, vapour pressures and enthalpies of sublimation, and enthalpies of formation of 2-methylpropanamide, 2,2-dimethylpropanamide, and 1-adamantyl carboxamide

Abstract The energies of combustion of 2-methylpropanamide, 2,2-dimethylpropanamide, and 1-adamantyl carboxamide have been determined using a static bomb calorimeter. The vapour pressures have been measured over a temperature range of about 15 K by the Knudsen-effusion technique. From the experimental results the following quantities for the three compounds, at 298.15 K, have been derived: Compound Δ f H m o (cr) Δ sub H m o Δ f H m o (g) kJ·mol −1 kJ·mol −1 kJ·mol −1 2-Methylpropanamide −368.6 ± 0.9 86.0 ± 0.2 −282.6 ± 0.9 2,2-Dimethylpropanamide −399.7 ± 1.3 86.6 ± 0.4 −313.1 ± 1.4 1-Adamantyl carboxamide −427.0 ± 2.4 108.0 ± 0.5 −319.0 ± 2.5 The structural effects on the thermochemical properties have been studied.

Thermochemistry of p-ethylbenzoic acid

Abstract The energy of combustion of a very pure sample of p -ethylbenzoic acid has been determined using a static bomb calorimeter. The vapour pressures of the acid have been measured over a range of temperatures near 298 K by the Knudsen-effusion technique. From the experimental results the following standard thermochemical quantities, at 298.15 K have been derived for p -C 6 H 4 (C 2 H 5 )CO 2 H:Δ f H m o (cr) = −(454.5 ± 1.9) kJ · mol −1 , Δ sub H m o = (98.9 ± 0.2) kJ · mol −1 , and Δ f H m o (g) = −(355.6 ± 1.9) kJ · mol −1 .

Thermochemical properties of 1,2,4,5-tetramethylbenzene pentamethylbenzene, and hexamethylbenzene

Abstract The energies of combustion of 1,2,4,5-tetramethylbenzene and pentamethylbenzene have been measured using a static bomb calorimeter. The vapour pressures of these compounds and of hexamethylbenzene have been measured over a temperature range of about 15 K by the Knudsen-effusion technique. From the experimental results of this work and our previously published thermochemical quantities the following results, at 298.15 K, for the three polymethylbenzenes studied have been derived: Δ f H m o (cr) Δ sub H m o Δ f H m o (g) kJ·mol −1 kJ·mol −1 kJ·mol −1 1,2,4,5-Tetramethylbenzene −121.7 ± 1.9 74.6 ± 0.3 −47.1 ± 1.9 Pentamethylbenzene −144.6 ± 2.2 77.4 ± 0.4 −67.2 ± 2.2 Hexamethylbenzene −162.4 ± 2.5 85.0 ± 0.2 −77.4 ± 2.5

Thermochemical properties of N-heterocyclic compounds IV. Enthalpies of combustion, vapour pressures and enthalpies of sublimation, and enthalpies of formation of 2-methylimidazole and 2-ethylimidazole

The energies of combustion of 2-methylimidazole and 2-ethylimidazole have been determined using a static bomb calorimeter. The vapour pressures have been measured over a temperature range of about 17 K by the Knudsen-effusion technique. From the experimental results the following quantities for the two compounds at T = 298.15 K have been derived: Download : Download full-size image

Structural effects on the thermochemical properties of organic compounds III. Enthalpies of combustion, vapour pressures and enthalpies of sublimation, and standard enthalpies of formation in the gaseous phase, of adamantane-1-carboxylic acid methyl ester and of adamantane-1-carbonitrile

The energies of combustion of adamantane-1-carboxylic acid methyl ester, and adamantane-1-carbonitrile have been determined using a static bomb calorimeter. The vapour pressures have been measured over a temperature range of about 18 K by the Knudsen-effusion technique. From the experimental results the following quantities for the two compounds, at T = 298.15 K, have been derived: Download : Download full-size image