脂肪酸酯的自由体积理论黏度模型

Free-Volume Theory Viscosity Model of Fatty Acid Esters

在对文献中发表的22种脂肪酸甲酯和16种脂肪酸乙酯的液相黏度实验数据进行收集的基础上,建立了脂肪酸酯类物质的自由体积理论黏度模型,并得到了模型的参数。结果表明,对脂肪酸甲酯而言,实验值和计算值的最大偏差小于5.5%(其中脂肪酸链的碳原子数与不饱和键数之比为20∶1和22∶1的除外),对脂肪酸乙酯,最大偏差小于4.0%(其中脂肪酸链的碳原子数与不饱和键数之比为18∶1和18∶2的除外)。分析发现,模型参数与酯类相对分子质量之间存在一定的规律,获得了其定量关系,使得所建立的模型具有了预测同类物质黏度的功能。将预测模型计算结果和实验值进行比较发现,对38种脂肪酸酯类,黏度总体平均相对偏差小于1%,可以满足实际工程的需要。

The experimental data of viscosity of 22 fatty acid methyl esters and 16 fatty acid ethyl esters are collected from literatures, the free volume theory based viscosity model of these esters is established and the coefficients in the model are obtained. Investigation shows that the coefficients in the model exhibit regular trends along with the molecular weight of the esters. The relationship between the coefficients and the molecular weight is obtained, and the predictive viscosity values using the relationship are compared with the literature data. Results show that the maximum relative deviation between the calculated viscosity values and those from literatures is lower than 5.5% for fatty acid methyl esters （except for C20：1 and C22：1） and 4.0% for fatty acid ethyl esters （except for C18＂1 andC18＂2）. For these 38 esters, the overall average relative deviation is less than 1%, indicating that this predictive model could meet the requirements of practical engineering