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The standard (p° = 0.1 MPa) molar enthalpies of combustion, ΔcHm°, for crystalline 2-furanacrylic acid, 3-furanacrylic acid, and 3-(2-furyl)-2-propenal and for the liquid 2-furanacrylonitrile were determined, at the temperature 298.15 K, using a static bomb combustion calorimeter. For these compounds, the standard molar enthalpies of phase transition, Δcr,lgHm°, at T = 298.15 K, were determined by Calvet microcalorimetry. For the two crystalline furanacrylic acids the vapour pressures as function of temperature were measured by the Knudsen effusion technique and the standard molar enthalpies of sublimation, ΔcrgHm°, at T = 298.15 K were derived by the Clausius–Clapeyron equation. The results are as follows:  相似文献   

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The standard (p° = 0.1 MPa) molar enthalpies of formation, in the gaseous state, at T = 298.15 K, for 2,5-dimethyl-3-furancarboxylic acid, 3-acetyl-2,5-dimethylfuran, and 4,5-dimethyl-2-furaldehyde were derived from the values of the standard molar enthalpies of formation, in the condensed phase, and the standard molar enthalpies of phase transition from the condensed to the gaseous state. The values of the standard molar enthalpies of formation of the compounds in the condensed phases were calculated from the measurements of the standard massic energies of combustion obtained by static bomb combustion calorimetry. The enthalpies of vaporization/sublimation were measured by Calvet high temperature microcalorimetry. For 2,5-dimethyl-3-furancarboxylic acid the standard enthalpy of sublimation was also calculated, by the application of the Clausius–Clapeyron equation, to the temperature dependence of the vapor pressures measured by the Knudsen effusion technique.
Empty Cell-ΔcHm°(cr,l)/(kJ·mol-1)Δcr,lgHm°/(kJ·mol-1)
CalvetKnudsen
2-Furanacrylic acid (cr)3149.8 ± 0.5103.0 ± 0.7103.3 ± 0.5
3-Furanacrylic acid (cr)3151.5 ± 0.7104.9 ± 1.1106.8 ± 0.5
3-(2-Furyl)-2-propenal (cr)3425.7 ± 1.282.3 ± 0.4
2-Furanacrylonitrile (l)3562.5 ± 1.365.2 ± 0.6
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The standard (p° = 0.1 MPa) molar enthalpies of formation of 2-, 3-, and 4-chloronitrobenzene isomers, in the crystalline state, at T = 298.15 K, were derived from the standard (p° = 0.1 MPa) massic energies of combustion, in oxygen, at T = 298.15 K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of sublimation of the isomers, at T = 298.15 K, were obtained by high temperature Calvet microcalorimetry.
Compound-ΔfHm°(cr,l)/(kJ·mol-1)Δcr,lgHm°(T=298.15K)/kJ·mol-1
CalvetKnudsen
2,5-Dimethyl-3-furancarboxylic acid (cr)600.4 ± 1.599.0 ± 1.7100.9 ± 0.5
3-Acetyl-2,5-dimethylfuran (l)352.1 ± 1.857.5 ± 1.5
4,5-Dimethyl-2-furaldehyde (l)294.5 ± 1.757.7 ± 0.6
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Empty Cell-ΔcUm°(cr)/(kJ · mol?1)-ΔcHm°(cr)/(kJ · mol?1)-ΔcrgHm°/(kJ · mol?1)
2-Chloronitrobenzene2939.5 ± 0.718.7 ± 1.080.9 ± 1.5
3-Chloronitrobenzene2915.8 ± 0.842.4 ± 1.282.5 ± 1.5
4-Chloronitrobenzene2921.7 ± 1.436.5 ± 1.676.2 ± 2.1
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