化学学报 ›› 2004, Vol. 62 ›› Issue (24): 2415-2420. 上一篇    下一篇

研究论文

4,6-二甲氧基-2-嘧啶氨基甲酸甲酯的热力学研究

邢军1,2, 谭志诚1, 邸友莹1, 孙晓红3, 孙立贤1, 张涛1   

  1. 1. 中国科学院大连化学物理研究所, 热化学实验室, 大连, 116023;
    2. 大连大学化学与化学工程系, 大连, 116622;
    3. 西北大学化学研究所, 西安, 710069
  • 投稿日期:2004-01-30 修回日期:2004-09-11 发布日期:2014-02-17
  • 通讯作者: 谭志诚,E-mail:tzc@dicp.ac.cn E-mail:tzc@dicp.ac.cn
  • 基金资助:
    国家自然科学基金(No.20373072)资助项目.

Thermodynamic Study of Methyl N-(4,6-Dimethoxypyrimidin-2-yl)carbamate

XING Jun1,2, TAN Zhi-Cheng1, DI You-Ying1, SUN Xiao-Hong3, SUN Li-Xian1, ZHANG Tao1   

  1. 1. Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023;
    2. Department of Chemistry and Chemical Engineering, Dalian University, Dalian 116622;
    3. Department of Chemistry, Northwest University, Xi'an 710069
  • Received:2004-01-30 Revised:2004-09-11 Published:2014-02-17

用精密自动绝热量热计测定了自行合成并提纯的4,6-二甲氧基-2-嘧啶氨基甲酸甲酯在80~380 K温区的摩尔热容.实验结果表明,在345~360 K温区,该化合物有一固-液熔化过程.经两次重复测定,得其熔化温度、摩尔熔化焓以及熔化熵分别为:(357.201±0.080) K, (26.289±0.029) kJ·mol-1和(73.597±0.070) J·mol-1·K-1.通过分步熔化法得到该物质绝对纯样品的熔点为357.449 K.根据热力学关系和热容数据,计算出了该化合物相对于标准参考温度298.15 K的热力学函数.用DSC和TG热分析技术在300~500 K温区对该物质的热力学性质作了进一步研究,得到与绝热量热法一致的固-液熔化过程热力学参数,并得到该化合物蒸发过程的热力学参数:沸点为488.06 K,摩尔蒸发焓为81.73 kJ·mol-1.

关键词: 4,6-二甲氧基-2-嘧啶氨基甲酸甲酯, 绝热量热, 低温热容, 热力学性质, 热分析

The low-temperature heat capacities of the methyl N-(4,6-dimethoxypyrimidin-2-yl)carbamate were measured with an automatic adiabatic calorimeter over the temperature range from 80 to 380 K. A solid-liquid phase transition was observed at Tm=(357.201?0.080) K, and the molar enthalpy and entropy of fusion were determined to be (26.289?0.029) kJ·mol-1 and (73.597?0.070) J·K-1 ·mol-1, respectively. The purity, the real melting point (T1) and the ideal melting point without any impurity or with absolute purity (To) of the compound under investigation were determined to be 99.10 mol%, 357.085 and 357.449 K, respectively, through fractional melting method. The thermodynamic functions relative to the reference temperature 298.15 K were derived based on the heat capacity measurements. Further research on thermodynamic properties of this compound was carried out by means of TG-DTG and DSC techniques. The boiling point and the enthalpy of evaporation for the compound were determined to be 488.06 K and 81.73 kJ·mol-1, respectively.

Key words: methyl N-(4,6-dimethoxypyrimidin-2-yl)carbamate, adiabatic calorimetry, low-temperature heat capacity, thermodynamic function, TG-DTG, DSC