化学学报 ›› 1993, Vol. 51 ›› Issue (11): 1059-1065. 上一篇    下一篇

研究论文

mezo-和d, l-2, 3-二氯丁烷气态生成焓的测定

何俊;安绪武;胡日恒   

  1. 中国科学院化学研究所
  • 发布日期:1993-11-15

Measurements of enthalpies of formation of 2, 3-dichlorobutane in gaseous state

HE JUN;AN XUWU;HU RIHENG   

  • Published:1993-11-15

本文用直接量热法测量了298.15K时meso-和d, l-2, 3-二氯丁烷的液态蒸发焓值以及其混合物的液态燃烧焓值, 得到了它们的标准气态生成焓值, 考察了二氯烷烃分子内氯原子间的相互影响和相互作用对其气态生成焓值的影响。

关键词: 生成焓, 焓, 量热法, 氯丁烷

Two samples of pure mezo- and d, l-2,3-dichlorobutanes were obtained from their mixture by fractional distn., and their enthalpies of vaporization at 25?were measured by using an LKB-8721-3 vaporization calorimeter, they are 38.41 ?0.07 (mezo-) and 39.73 ?0.05 (d, l-) kJ/mol, resp. A mixture sample with (mezo-/ d, l-) = 1.34/1 was used for combustion experiments, its enthalpies of combustion at 25?were determine by using a rotating bomb combustion calorimeter with a tantanum lined bomb, as -2519.74 ?1.06 kJ/mol. By using the literature's enthalpies of isomerism between the liquid meso- and d, l-2,3-dichlorobutanes, -1.13 ?0.21 kJ/mol, measured by the equilibrium method, enthalpies of combustion of meso- and d, l-2,3-dichlorobutanes were obtained. Then enthalpies of formation of both in gaseous state were derived as, -202.34 ?1.72 (meso-) and -202.15 ?1.72 (d, l-) kJ/mol, resp. According to the following equation: a,b-C4H8Cl2(g) + n-C4H10(g) = a-C4H9Cl + b-C4H9Cl + DHr; the enthalpies of reaction are derived as +5.3(meso-) and +5.5(d, l-) kJ/mol, which are closed with that of 1,2-dichlorobutane. The determine enthalpies of formation of the meso- and d, l-2,3-dichlorobutanes also coincide with the calculation results of the authors' "Electrostatic Bond Energy Scheme".

Key words: ENTHALPY OF FORMATION, ENTHALPY, CALORIMETRY

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