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Comparative solubility study of carbon(60) and carbon(60)-piperazine and applications on quartz crystal microbalance/heat conduction calorimeter.

机译：碳（60）和碳（60）-哌嗪的溶解度比较研究及其在石英晶体微天平/导热量热仪中的应用。

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摘要

Although C60, Buckminsterfullerene, was discovered in 1985, it was not until Kratschmer and coworkers discovered in 1990 that C60 was soluble in benzene that the scientific literature exploded with experimental studies of these remarkable molecules. A large number of derivatives have been synthesized. However, some fundamental physical and chemical properties remain uncertain. Fullerene derivatives have some similarities with pure fullerene but there also exist a wide range of differences.;Studying the thermodynamics of fullerene solubility led to the discovery that at room temperature, the thermodynamically stable phase of a saturated solution of fullerenes is its presence as solvates, stoichiometric binary compounds of fullerene and solvent. The incongruent melting of these solvates accounts for a highly unusual maximum in the temperature-solubility curves for these systems. This behavior has also been found in fullerene derivatives particularly in C60-piperazine which we have synthesized in gram quantity.;The solubility of C60-piperazine has been measured in 12 aromatic solvents and the values have been compared with the solubility of C60 . Hypothetical solubility determinations by various thermodynamic relationships have been worked. Also, a Theoretical Linear Solvation Energy Relationship (TLSER) has been applied to describe a relationship between the solvents and C60/C60-piperazine. Besides organic solvents, the water solubility of C60-piperazine has been studied and an interesting, pH dependent, color change phenomenon has been studied.;We have developed a new, highly sensitive method for measuring simultaneously the mass change (to +/- 2 ng) and the resulting heat flow (to +/- 100 nW) in a thin film when exposed to a gas mixture of changing composition. We call the device a quartz crystal microbalance/heat conduction calorimeter (QCM/HCC).;Under isothermal conditions, a quartz crystal microbalance (QCM) is in intimate thermal contact with a heat flow sensor and thence to a heat sink. A sample QCM is coated with a thin film (0.1--20 mu). By introducing a slow flow of a nitrogen carrier gas with different known concentrations of water or organic solvent vapor to the QCM surface, we have been able to measure simultaneously the change in mass and the resulting heat flows from the film to the heat sink when the film sample takes up or releases solvent vapor.;Exposing to water and organic solvents, films of C60 and C 60-piperazine has been studied in the QCM/HCC. This sort of molecular crystal was a new application on QCM/HCC. Results from QCM/HCC were compared with other thermal analysis methods.;Commercial specialized and generic coating materials for pharmaceutical products were studied in QCN/HCC. Film samples were exposed to high humidity and high temperature. The absorption, desorption, and corresponding enthalpy and mechanical property changes were also measured.
机译：尽管1985年发现了C60，即Buckminsterfullerene，但直到Kratschmer和同事在1990年发现C60可溶于苯后，科学文献通过对这些杰出分子的实验研究使之爆炸。已经合成了大量的衍生物。但是，一些基本的物理和化学性质仍然不确定。富勒烯衍生物与纯富勒烯有一些相似之处，但也存在广泛的差异。研究富勒烯溶解度的热力学导致发现，在室温下，富勒烯饱和溶液的热力学稳定相是作为溶剂化物存在的，富勒烯和溶剂的化学计量二元化合物。这些溶剂化物的不完全融化导致这些系统的温度-溶解度曲线出现极大的异常。在以克为单位合成的富勒烯衍生物中，特别是在C60-哌嗪中，也发现了这种行为。;已经测量了C60-哌嗪在12种芳族溶剂中的溶解度，并将其值与C60的溶解度进行了比较。已经通过各种热力学关系确定了假设的溶解度。此外，理论线性溶剂能关系（TLSER）已用于描述溶剂与C60 / C60-哌嗪之间的关系。除有机溶剂外，还研究了C60-哌嗪的水溶性，并研究了一种有趣的，pH依赖性的变色现象。;我们开发了一种新的高度灵敏的方法，用于同时测量质量变化（至+/- 2 ng）和暴露在变化的气体混合物中时薄膜中产生的热流（至+/- 100 nW）。我们将该设备称为石英晶体微天平/导热热量计（QCM / HCC）。在等温条件下，石英晶体微天平（QCM）与热流量传感器紧密热接触，并由此进入散热器。 QCM样品涂有薄膜（0.1--20微米）。通过将缓慢流动的氮气载气与已知的不同浓度的水或有机溶剂蒸气一起引入QCM表面，我们能够同时测量质量的变化，并且当温度变化时，热量从薄膜流到散热片。薄膜样品吸收或释放溶剂蒸气。;在水和有机溶剂中，已在QCM / HCC中研究了C60和C 60-哌嗪的薄膜。这种分子晶体是在QCM / HCC上的新应用。将QCM / HCC的结果与其他热分析方法进行了比较。;在QCN / HCC中研究了医药产品的商业专用和通用涂料。膜样品暴露在高湿度和高温下。还测量了吸收，解吸以及相应的焓和机械性能变化。

著录项

  • 作者

    Tian, Jun.;

  • 作者单位

    Drexel University.;

  • 授予单位 Drexel University.;
  • 学科 Chemistry Analytical.;Chemistry Physical.
  • 学位 Ph.D.
  • 年度 2002
  • 页码 201 p.
  • 总页数 201
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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