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Thermodynamic properties of isomeric ethyl esters of 2-cyano-3- [5- (2,3,4-nitrophenyl) -2-furan] acrylic acid
Authors: R.V. Kos, I.B. Sobechko, Y.I. Horak, V.V. Sergeev, L.V. Goshko
Number of views: 358
The thermodynamic properties of isomeric ethyl esters of 2-cyano-3- [5- (2,3,4- nitrophenyl)- 2-furan] acrylic acid were determined for the first time. Using temperature dependences of vapor pressure, which were determined via effusion method by Knudsen, the sublimation enthalpies (in kJ mol-1) of the ethyl ester of 2-cyano- 3-[5- (2-nitrophenyl)- 2-furan] acrylic acid, ethyl ester of 2-cyano-3- [5-(3- nitrophenyl)- 2-furan] acrylic acid, and ethyl ester of 2-cyano-3- [5-(4- nitrophenyl)- 2-furan] acrylic acid were calculated to be equal to ΔsubН402.5-422.1 = 139.3 ± 6.1, ΔsubН430.2-448.4 = 142.7 ± 7.1, and ΔsubН430.4-452.4 =176.0 ± 9.6, respectively. Using bomb calorimetry method, the values of combustion energy, the enthalpies of combustion and formation in condensed state (in kJ mol-1) of the ethyl ester of 2-cyano- 3-[5-(2-nitrophenyl)- 2-furan] acrylic acid, 2-cyano- 3-[5- (3-nitrophenyl)- 2-furan] acrylic acid, and 2-cyano-3- [5-(4-nitrophenyl)- 2-furan] acrylic acid were calculated to be equal to ΔUс298 = -7758.4 ± 4.7, ΔсН0298 = -7763.3 ± 4.7, ΔfH0298 = -247.8 ± 4.7; ΔUс298 = -7728.8 ± 6.3, ΔсН0298 = -7735.0 ± 6.3, ΔfH0298 = -277.4 ± 6.3; and ΔUс298 = -7700.2 ± 8.9, ΔсН0298 = -7705.2 ± 8.9, ΔfH0298 = -306.0±8.9, respectively. The values of the enthalpy of formation in gaseous state (in kJ mol-1) were calculated based on the values of the sublimation enthalpies at 298 K for ethyl ester of 2-cyano- 3-[5-(2-nitrophenyl)- 2-furan] acrylic acid, ethyl ester of 2-cyano- 3-[5-(3-nitrophenyl)- 2-furan] acrylic acid, and ethyl ester of 2-cyano-3- [5-(4-nitrophenyl)- 2-furan] acrylic acid as follows: ΔfH0298 = -100 ± 11, ΔsubН0298 = 147.2 ± 9.8; ΔfH0298 = -124 ± 13, ΔsubН0298 = 153 ± 11; and ΔfH0298 = -120 ± 14, ΔsubН0298 =186 ± 15, respectively.