大学化学 >> 2023, Vol. 38 >> Issue (1): 169-173.doi: 10.3866/PKU.DXHX202201025

化学实验 上一篇    下一篇

沸点升高法测化合物相对分子量实验的改进

熊辉(), 吴贝娜, 范子鑫, 郑子豪, 静恩哲, 莫婉玲, 龚跃法   

  • 收稿日期:2022-01-16 录用日期:2022-03-21 发布日期:2022-04-02
  • 通讯作者: 熊辉 E-mail:xionghui@mail.hust.edu.cn
  • 基金资助:
    华中科技大学教学研究项目(2019028);湖北高校省级教学研究项目(2018078)

Improvement in the Measurement Method for the Relative Molecular Weight of Compounds Based on Boiling Point Elevation

Hui Xiong(), Beina Wu, Zixin Fan, Zihao Zheng, Enzhe Jing, Wanling Mo, Yuefa Gong   

  • Received:2022-01-16 Accepted:2022-03-21 Published:2022-04-02
  • Contact: Hui Xiong E-mail:xionghui@mail.hust.edu.cn

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摘要：

物理化学手段测化合物分子量是基础化学实验中的经典实验方法，也是本科生化学实验中重要的一项训练。现有的测量方法存在实验体系不环保、实验误差大、操作步骤难以控制且实验时间长等缺陷。基于实验的绿色化理念以及“两性一度”的教学要求，对现有沸点升高法测分子量的实验方法进行探索：以异丙醇代替环己烷(丙酮)作为溶剂、苯甲酸代替萘作为溶质，采用水浴与电热棒双重加热的方式，配置数字千分温度计提高测量精度。改进后实验试剂绿色环保、设备操作简单、装置抗干扰能力强、方法重现性好且测量误差减小。立足基础，落实高阶，重视挑战，加强了学生对稀溶液依数性的理解，培养了他们实践创新的思维。

关键词: 沸点升高法, 分子量测定, 实验改进, 异丙醇, 苯甲酸

Abstract:

The physicochemical method is a classic experimental method in basic chemistry and also an important component of experimental training in undergraduate chemistry courses. However, existing measurement methods exhibit some drawbacks in terms of a lack of environmental protection of the experimental system, introduction of experimental errors, difficulty with controlling the operation steps, and a long experimental time. Based on green chemistry experiments and advanced, innovative, and challenging teaching requirements, the existing boiling point elevation method for measuring the molecular weight of compounds was explored. In the experiment, isopropanol instead of cyclohexane (acetone) was used as the solvent, benzoic acid instead of naphthalene was used as the solute, a water bath and electric heating rod were used for double heating, and a digital micrometer thermometer was affixed to the apparatus to improve the measurement accuracy. With these experimental improvements, the reagent was green, equipment was easy to operate, anti-interference ability of the device was strong, experimental reproducibility was good, and measurement error was reduced. Based on the foundation, the implementation of high-level, attach importance to challenges, the students' understanding of the number dependence of dilute solution is strengthened, and their practical and innovative thinking is cultivated.

Key words: Boiling point elevation method, Determination of molecular weight, Experimental improvement, Isopropanol, Benzoic acid