Thermodynamic properties of molecular organic crystals containing nitrogen, oxygen, and sulfur II. Molar heat capacities of eight compounds by adiabatic calorimetry

Wit, H. G. M. de; Kruif, C. G. de; Miltenburg, J.C. van

doi:10.1016/0021-9614(83)90095-2

Cited by 51 publications

(18 citation statements)

References 8 publications

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“…The enthalpy of sublimation at 298.15 K was reported by Jimé nez et al (1987). Isobaric heat capacities for solid imidazole (De Wit et al, 1983) were converted to a smooth function via cubic spline and integrated using Mathematica 9.0.1 (Wolfram Research Inc,., 2012). The enthalpy of gaseous imidazole at various temperatures was computed using equations (14) and (15).…”

Section: A3 Acetic Acidmentioning

confidence: 99%

How important is thermal expansion for predicting molecular crystal structures and thermochemistry at finite temperatures?

Heit

Beran

2016

Acta Crystallogr B Struct Sci Cryst Eng Mater

108

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Molecular crystals expand appreciably upon heating due to both zero-point and thermal vibrational motion, yet this expansion is often neglected in molecular crystal modeling studies. Here, a quasi-harmonic approximation is coupled with fragment-based hybrid many-body interaction calculations to predict thermal expansion and finite-temperature thermochemical properties in crystalline carbon dioxide, ice Ih, acetic acid and imidazole. Fragment-based second-order Möller-Plesset perturbation theory (MP2) and coupled cluster theory with singles, doubles and perturbative triples [CCSD(T)] predict the thermal expansion and the temperature dependence of the enthalpies, entropies and Gibbs free energies of sublimation in good agreement with experiment. The errors introduced by neglecting thermal expansion in the enthalpy and entropy cancel somewhat in the Gibbs free energy. The resulting ∼ 1-2 kJ mol(-1) errors in the free energy near room temperature are comparable to or smaller than the errors expected from the electronic structure treatment, but they may be sufficiently large to affect free-energy rankings among energetically close polymorphs.

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Section: A3 Acetic Acidmentioning

confidence: 99%

How important is thermal expansion for predicting molecular crystal structures and thermochemistry at finite temperatures?

Heit

Beran

2016

Acta Crystallogr B Struct Sci Cryst Eng Mater

108

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“…Although the thermochemical properties of MEL and CYA have been investigated in the condensed phase, the gas-phase studies are very limited [32][33][34][35]. Some important questions regarding the intrinsic properties of these two compounds remain unanswered.…”

mentioning

confidence: 99%

Gas-phase acid-base properties of melamine and cyanuric acid

Mukherjee

Ren

2010

J. Am. Soc. Mass Spectrom.

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The thermochemical properties of melamine and cyanuric acid were characterized using mass spectrometry measurements along with computational studies. A triple-quadrupole mass spectrometer was employed with the application of the extended Cooks kinetic method. The proton affinity (PA), gas-phase basicity (GB), and protonation entropy (⌬ p S) of melamine were determined to be 226.2 Ϯ 2.0 kcal/mol, 218.4 Ϯ 2.0 kcal/mol, and 26.2 Ϯ 2.0 cal/mol K, respectively. The deprotonation enthalpy (⌬ acid H), gas-phase acidity (⌬ acid G), and deprotonation entropy (⌬ acid S) of cyanuric acid were determined to be 330.7 Ϯ 2.0 kcal/mol, 322.9 Ϯ 2.0 kcal/mol, and 26.1 Ϯ 2.0 cal/mol K, respectively. The geometries and energetics of melamine, cyanuric acid, and related ionic species were calculated at the B3LYP/6-31ϩG(d) level of theory. The computationally predicted proton affinity of melamine (225.9 kcal/mol) and gas-phase deprotonation enthalpy of cyanuric acid (328.4 kcal/mol) agree well with the experimental results. Melamine is best represented as the imide-like triazine-triamine form and the triazine nitrogen is more basic than the amino group nitrogen. Cyanuric acid is best represented as the keto-like tautomer and the N-H group is the most probable proton donor. (J Am Soc Mass Spectrom 2010, 21, 1720 -1729

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“…Some enthalpies of protonation and proton affinities have been determined using NMR, (4) kinetic methods, (5) electrostatically trained neural networks, (6) and adiabatic calorimetry. (7) Imidazole has also been studied in complexes with various metal ions and as part of histidine using NMR and x-ray crystallography. (8) In this paper, we report the apparent molar volumes V φ and apparent molar heat capacities C p,φ for aqueous imidazole and imidazolium chloride solutions.…”

Section: -9614/02mentioning

confidence: 99%

Thermodynamics for proton dissociation from aqueous imidazolium ion at temperatures from 278.15 K to 393.15 K and at the pressure 0.35 MPa: apparent molar volumes and apparent molar heat capacities of the protonated and neutral imidazole

Jardine

Patterson

Origlia

et al. 2002

The Journal of Chemical Thermodynamics

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Thermodynamic properties of molecular organic crystals containing nitrogen, oxygen, and sulfur II. Molar heat capacities of eight compounds by adiabatic calorimetry

Cited by 51 publications

References 8 publications

How important is thermal expansion for predicting molecular crystal structures and thermochemistry at finite temperatures?

How important is thermal expansion for predicting molecular crystal structures and thermochemistry at finite temperatures?

Gas-phase acid-base properties of melamine and cyanuric acid

Thermodynamics for proton dissociation from aqueous imidazolium ion at temperatures from 278.15 K to 393.15 K and at the pressure 0.35 MPa: apparent molar volumes and apparent molar heat capacities of the protonated and neutral imidazole

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