Please wait a minute...
Acta Physico-Chimica Sinica  2009, Vol. 25 Issue (12): 2417-2421    DOI: 10.3866/PKU.WHXB20091120
Article     
Enthalpy of Formation, Heat Capacity and Entropy of Melamine
LIU Peng, XIONG Wei, HU Shan-Zhou, LI Xi, TAN Zhi-Cheng
Deparment of Chemistry, School of Sciences, Wuhan University of Technology, Wuhan 430070, P. R. China; Thermochemisty Laboratory and China Ionic Liquid Laoratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning Province, P. R. China
Download:   PDF(263KB) Export: BibTeX | EndNote (RIS)      

Abstract  

The thermodynamic properties of melamine were studied by multiple thermochemical methods. A bomb combustion calorimeter was used to determine the combustion heat of melamine at 298.15 K. According to the results, we calculated the standard molar enthalpy of combustion and standard molar enthalpy of formation of melamine: △cHΘm=(-2455.17±4.65) kJ·mol-1; △fHΘm =(-763.38±5.16) kJ·mol-1. The bond enthalpy of C≈N (between single bond and double bond) in melamine was then estimated to be 458.30 kJ·mol -1 according to the ralationship between bond enthalpy and combustion enthalpy. This value is larger than that of C—N but smaller than that of C=N. Heat capacity measurements were carried out in a small sample adiabatic calorimeter from 80 to 385 K. We obtained △fHΘm at different temperatures between 80 and 385 K using the heat capacity data. Through calculation with the values of heat capacity, the relationship between the standard molar enthalpy of formation and temperature is also presented as a functional equation. We also measured the thermol stability of melamine by the thermogravimetry-differential scanning calorimetry (TG-DSC) technique, which showed a thermal decomposition peak at 603.37 K for the DSC curve.



Key wordsHeat capacity      Melamine      Combustion heat      Adiabatic calorimeter     
Received: 10 July 2009      Published: 28 September 2009
MSC2000:  O642  
Corresponding Authors: LIU Peng     E-mail: chemliup@whut.edu.cn
Cite this article:

LIU Peng, XIONG Wei, HU Shan-Zhou, LI Xi, TAN Zhi-Cheng. Enthalpy of Formation, Heat Capacity and Entropy of Melamine. Acta Physico-Chimica Sinica, 2009, 25(12): 2417-2421.

URL:

http://www.whxb.pku.edu.cn/Jwk_wk/wlhx/10.3866/PKU.WHXB20091120     OR     http://www.whxb.pku.edu.cn/Jwk_wk/wlhx/Y2009/V25/I12/2417

[1] WANG Li, SHI He-Xia, WANG Wen-Yuan, SHI Hong, SHAO Xiang. Identifying the Hydrogen Bonding Patterns of Melamine and Melem Self-Assemblies on Au(111) Surface[J]. Acta Physico-Chimica Sinica, 2017, 33(2): 393-398.
[2] JIN Cheng-Wei, WANG Ye, XU Su-Ling, ZHANG Jian-Jun. Synthesis, Crystal Structures and Thermochemical Properties of Ternary Rare Earth Complexes Based on 3,4-Diethoxybenzoic Acid and 2,2'-Bipyridine[J]. Acta Physico-Chimica Sinica, 2016, 32(9): 2232-2240.
[3] ZHANG Xiao-Ye, XUE Bin, CHENG Ze, TAN Zhi-Cheng, SHI Quan. Low Temperature Heat Capacities of Uracil and 5-Bromouracil[J]. Acta Physico-Chimica Sinica, 2015, 31(3): 412-418.
[4] ZHENG Ling, FAN Ben-Han, BU Xiao-Xue, PAN Yi, DONG Jia-Xin, GUAN Wei. Study on Thermodynamic Properties of Ionic Liquid 1-Ethyl-3-methylimidazolium Alanine[J]. Acta Physico-Chimica Sinica, 2015, 31(11): 2036-2042.
[5] LU Jian-Jian, YING Zong-Rong, LIU Xin-Dong, ZHAO Shuang-Sheng. Preparation of Cross-Linked Porous Carbon Nanofiber Networks by Electrospinning Method and Their Electrochemical Capacitive Behaviors[J]. Acta Physico-Chimica Sinica, 2015, 31(11): 2099-2108.
[6] GAO Xiao-Han, XU Pei, DUAN Wen-Chao, LÜ Xue-Chuan, TAN Zhi-Cheng, LU Qiang. Low-Temperature Heat Capacity and Thermodynamic Functions of Ho(NO3)3(C2H5O2N)4·H2O[J]. Acta Physico-Chimica Sinica, 2013, 29(10): 2123-2128.
[7] ZHANG Guo-Chun, ZHOU Chun-Sheng, GAO Sheng-Li. Low Temperature Heat Capacities and Standard Molar Enthalpy of Formation of the Coordination Compound Zn(Met)3(NO3)2·H2O(s)(Met=L-α-Methionine)[J]. Acta Physico-Chimica Sinica, 2013, 29(10): 2129-2134.
[8] LI Shang, WANG Jia-Tang, CHEN Rui-Xin, ZHAO Wei, QIAN Liu, PAN Mu. Catalytic Performance of Heat-Treated Fe-Melamine/C and Fe-g-C3N4/C Electrocatalysts for Oxygen Reduction Reaction[J]. Acta Physico-Chimica Sinica, 2013, 29(04): 792-798.
[9] LIU Bei-Ping, TAN Zhi-Cheng. Thermodynamic Properties of Nd(Gly)2Cl3·3H2O and Pr(Ala)3Cl3·3H2O[J]. Acta Physico-Chimica Sinica, 2013, 29(01): 17-22.
[10] CHEN Zhong-Xiu, CAO Chen, DENG Shao-Ping. Chaotrope-Assisted Color Visualization Mechanism and Thermodynamics Involved in Molecular Recognition of Melamine by Bolaamphiphiles Embedded in Polydiacetylene Vesicles[J]. Acta Physico-Chimica Sinica, 2012, 28(06): 1320-1328.
[11] WANG Wen-Qing, SHEN Xin-Chun, WU Ji-Lan, GONG Yan, SHEN Guo-Hua, ZHAO Hong-Kai. Heat Capacity and DC-Magnetic Susceptibility Evidence for the Asymmetry of Electron Spin-Flip Phase Transition of N+H…O- Bond in Chiral Alanine Crystal[J]. Acta Physico-Chimica Sinica, 2012, 28(04): 773-780.
[12] WANG Wen-Qing, SHEN Xin-Chun, GONG Yan. Cryogenic Magnetic Transition of D- and L-Alanine: Magnetic Field Dependence of Specific Heat and DC Magnetic Susceptibility[J]. Acta Physico-Chimica Sinica, 2010, 26(10): 2597-2603.
[13] XU Fen, QIU Shu-Jun, LIANG Jian-Guo, WU Rui-Hua, SUN Li-Xian, LI Fen. Low Temperature Heat Capacity and Thermal Analysis of Caffeine, Theophylline and Aminophylline[J]. Acta Physico-Chimica Sinica, 2010, 26(08): 2096-2102.
[14] LV Xue-Chuan, TAN Zhi-Cheng, GAO Xiao-Han. Synthesis and Thermochemical Properties of New Ternary Lanthanum Complex La(Glu)(Im)6(ClO4)3·4HClO4·4H2O[J]. Acta Physico-Chimica Sinica, 2009, 25(10): 1945-1950.
[15] ZHONG Ai-Guo, WU Jun-Yong, YAN Hua, JIN Yan-Xian, DAI Guo-Liang, JIANG Hua-Jiang, PAN Fu-You, LIU Shu-Bin. Structure, UV-Vis Spectroscopy and Reactivity Properties of MelamineMetal(II) Complexes[J]. Acta Physico-Chimica Sinica, 2009, 25(07): 1367-1372.