| 2-甲基-2-丁醇的低温热容和热力学性质 |
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| 引用本文： | 童波a,b 谭志诚a,c 王韶旭c. 2-甲基-2-丁醇的低温热容和热力学性质[J]. 中国化学, 2008, 26(9): 1561-1566. DOI: 10.1002/cjoc.200890282 |
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| 作者姓名： | 童波a b 谭志诚a c 王韶旭c |
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| 作者单位： | a中国科学院大连化学物理研究所热化学实验室, 辽宁 大连 116023； ;a中国科学院研究生院, 北京 100049； ;C大连交通大学环境与化学工程学院，辽宁 大连 116028 ; |
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| 摘 要： | 本文用精密自动绝热量热仪测定了2-甲基-2-丁醇在80～305 K温区的热容，从热容曲线(Cp-T) 发现三个固－固相变和一个固－液相变, 其相变温度分别为T = 146.355, 149.929, 214.395, 262.706 K。从实验热容数据用最小二乘法得到以下四个温区的热容拟合方程。在80～140K温区, Cp,m = 39.208 + 8.0724X - 1.9583X2 + 10.06X3 + 1.799X4 - 7.2778X5 + 1.4919X6, 折合温度X = (T –110) / 30; 在 155 ～ 210 K温区, Cp,m = 70.701 + 10.631X + 12.767X2 + 0.3583X3 - 22.272X4 - 0.417X5 + 12.055X6, X = (T –182.5) /27.5; 在220 ～ 250 K温区, Cp,m = 99.176 + 7.7199X - 26.138X2 + 28.949X3 + 0.7599X4 - 25.823X5 + 21.131X6, X = (T – 235)/15; 在 270～305 K温区, Cp,m =121.73 + 16.53 X- 1.0732X2 - 34.937X3 - 19.865X4 + 24.324X5 + 18.544X6, X = (T –287.5)/17.5。从实验热容计算出相变焓分别为0.9392, 1.541, 0.6646, 2.239 kJ×mol-1; 相变熵分别为6.417, 10.28, 3.100, 8.527 J×K-1×mol-1。根据热力学函数关系式计算出80～305 K温区每隔5 K的热力学函数值 [HT –H298.15]和 [ST –S298.15]。
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| 关 键 词： | 2-甲基-2-丁醇 热容 相变 热力学性质 |
| 收稿时间： | 2008-01-25 |
| 修稿时间： | 2008-03-10 |
Low Temperature Heat Capacities and Thermodynamic Properties of 2‐Methyl‐2‐butanol |
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| Bo TONG,Zhi‐Cheng TAN,Shao‐Xu WANG. Low Temperature Heat Capacities and Thermodynamic Properties of 2‐Methyl‐2‐butanol[J]. Chinese Journal of Chemistry, 2008, 26(9): 1561-1566. DOI: 10.1002/cjoc.200890282 |
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| Authors: | Bo TONG Zhi‐Cheng TAN Shao‐Xu WANG |
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| Affiliation: | 1. Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China;2. Graduate School of the Chinese Academy of Sciences, Beijing 100049, China;3. College of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian, Liaoning 116028, China;4. Tel.: 0086‐0411‐84379199;5. Fax: 0086‐0411‐84685940 |
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| Abstract: | The low‐temperature heat capacity Cp,m of 2‐methyl‐2‐butanol was precisely measured in the temperature range from 80 to 305 K by means of a small sample automated adiabatic calorimeter. Three solid‐solid phase transitions and one solid‐liquid phase transition were found at T=146.355, 149.929, 214.395 and 262.706 K from the experimental Cp‐T curve, respectively. The dependence of heat capacity on temperature was fitted to the following polynomial equations with a least square method. In the temperature range of 80 to 140 K, Cp,m=39.208+8.0724X?1.9583X2+10.06X3+1.799X4?7.2778X5+1.4919X6, X= (T?110)/30; in the temperature range of 155 to 210 K, Cp,m=70.701+10.631X+12.767X2+0.3583X3?22.272X4?0.417X5+12.055X6, X= (T?182.5)/27.5; in the temperature range of 220 to 250 K, Cp,m=99.176+7.7199X?26.138X2+28.949X3+0.7599X4?25.823X5+21.131X6, X= (T?235)/15; and in the temperature range of 270 to 305 K, Cp,m=121.73+16.53X?1.0732X2?34.937X3?19.865X4+24.324X5+18.544X6, X= (T?287.5)/17.5. The molar enthalpies of these transitions were determined to be 0.9392, 1.541, 0.6646 and 2.239 kJ·mol?1, respectively. The molar entropies of these transitions were determined to be 6.417, 10.28, 3.100 and 8.527 J·K?1·mol?1, respectively. The thermodynamic functions [HT?H298.15] and[ST?S298.15], were derived from the heat capacity data in the temperature range of 80 to 305 K with an interval of 5 K. |
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| Keywords: | 2‐methyl‐2‐butanol heat capacity phase transition thermodynamic property |
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