DSC法测定2,6-二叔丁基对甲酚-乙醇溶液的比热容

采用DSC法测定了2,6-二叔丁基对甲酚(BHT)-乙醇溶液在293.15～323.15 K温度范围及BHT含量(w)在0～20%内的质量定压热容(Cp),同时将BHT-乙醇溶液的Cp与BHT含量和温度进行了关联,利用最小二乘法回归,推导出计算Cp的方程;利用此方程对实验中的35个数据点进行计算,并将计算值与实验值进行比较。实验结果表明,BHT-乙醇溶液的Cp随温度(T)的升高而增大,随BHT含量的增加而减小;Cp关于T和w两参数的方程为Cp=-3.9×10-6T3+0.003 7T2-1.142 3T+120.01+(2.6×10-5T3-0.024 5T2+7.617 9T-787.30)w;对比计算值与实验值可知,35个数据点的平均相对误差为0.79%;此方程可计算BHT-乙醇溶液在一定温度和组成下的Cp,为以无水乙醇为溶剂的溶液结晶提纯BHT及相关体系热量平衡的计算提供了可靠依据。

Determination of Specific Heat Capacity of Butylated Hydroxytoluene-Ethanol Binary System by DSC Method

The specific heat capacity(Cp) of butylated hydroxytoluene(BHT)-ethanol solution was measured by differential scanning calorimetry in the temperature range of 293.15-323.15 K and the BHT concentration(w) range of 0-20%.The Cp was correlated with BHT content and the temperature(T).The coefficients in the correlated equations were obtained by least-square regression method.The results showed that the Cp of BHT-ethanol solution increased with the temperature rise and decreased with the BHT content rise.A equation Cp=-3.9×10-6T3+0.003 7T21.142 3T+120.01+(2.6×10-5T3-0.024 5T2+7.617 9T-787.30)w for calculating the Cp was derived.By this equation,Cp can be calculated at different temperatures and BHT contents.The calculated values were compared with the experimental data.The average relative error for the 35 data points was 0.79%.