Assessment of systematic errors in measurement of vapor pressures by thermogravimetric analysis
- 作者：Federica Barontini ; Valerio Cozzani
- 关键词：Thermogravimetric analysis ; Evaporation rate ; Vapor pressure ; Diffusive evaporation ; Data analysis
- 刊名：Thermochimica Acta
- 出版年：2007
- 期刊代码：110_00406031
- 类别：ch
- 出版时间：25 August 2007
- 卷：460
- 期：1-2
- 页码：15-21
- 文件大小：417 K
摘要
The present study explores the application of the diffusion limited evaporation theory to the estimation of vapor pressure from TG experimental data. A simplified method was developed to calculate the apparent values of the vapor pressure of pure substances from TG data, based on isothermal TG runs with crucibles having different surface areas available for evaporation. Antoine parameters are estimated through a numerical procedure based on a non-linear least square algorithm. The procedure also evaluates the substance diffusivity in nitrogen. The methodology developed might be used for a preliminary screening of the vapor pressure of pure compounds, due to the limited amounts of sample that are necessary and to the limited time frame required for the experimental runs. However, the estimation of diffusivity and vapor pressures values by the TG technique is possible with limited accuracy. Possible sources of error were thoroughly investigated and discussed.