差示扫描量热法测定戊二酸熔点及其比热容

Determination of melting point and specific heat capacity of glutaric acid by differential scanning calorimetry

熔点是反映产品纯度的重要指标之一,戊二酸的纯度对其下游产品聚酯多元醇等应用具有较大的影响。实验通过差示扫描量热仪(DSC)表征戊二酸熔化过程中相变吸热情况,测定戊二酸的熔点,与传统的毛细管法相比,操作更简单、分辨率更高和重复性更好。实验结果显示,受热传递过程影响,减小升温速率和样品质量能减小热量传递滞后的影响。使用origin对DSC曲线进行处理,在样品质量为6mg和升温速率为0.5℃条件下,测得戊二酸的熔点范围为97.61~98.61℃,计算得到戊二酸熔化焓为163.00J/g,通过蓝宝石法计算得到比热容为2.2657J/(g+K)。

The purity of glutaric acid has a great impact on the application of its downstream products such as polyester polyol.The melting point is one of the important indexes reflecting product purity.The experimental results show that,influenced by the heat transfer process,reducing the heating rate and sample quantity can reduce the influence of heat transfer delay.The DSC curve was processed by origin.The melting point range of glutaric acid was 97.61—98.61℃under the condition that the sample volume was 6mg and the heating rate was 0.5℃/min,and the melting enthalpy of glutaric acid was calculated to be 163.00J/g,and the specific heat capacity was calculated by sapphire method was 2.2657J/(g˖K).Compared with the traditional capillary method,this method has simpler operation,higher resolution,and better repeatability.