A thermal analysis study of long chain fatty acids

摘要

The purpose of this study is to examine the thermal behavior of saturated fatty acid (CH_3(CH_2)nCOOH], where n varies from n = 10 to n = 16, during heating. The studies were performed over a temperature range of ambience to 350 deg C in a flowing atmosphere of nitrogen, using a SDT 2960 simultaneous TGA-DTA unit. The acids showed two endotherms due to the melting at a lower temperature and vaporization at higher temperature, which is a zero order process. The influence of flow rate and heating rate on melting points was reported. The latent heat (triangle openH~#theta#) of vaporization process is calculated by the Antoine equation and Clausius-Clapeyron equation at different temperature range. The activation energy (E_(act)) was calculated from the rising temperature experiments, using the Arrhenius equation. These observations should be of use in characterization of pharmaceutical excipients.