有机蒸气-空气分子扩散系数实测数据及分析

利用自行研发的气体扩散系数测试装置，测定了烷烃、环烷烃、芳香烃、含氧化合物（酯类、醇类、酮类等）等21种挥发性有机化合物在空气中的分子扩散系数。测定结果表明：互为同系物的有机化合物在相同温度下，分子扩散系数随着分子链的增长而减小，与其沸点呈负相关；互为同分异构体的有机化合物在相同温度下，有支链的分子扩散系数比没有支链的要大。另外，将实验实测值与FSG方程计算值以及文献值进行了对比分析。通过比较实测值与计算值，认为大部分分子结构全部为单键并且不含环状结构的有机化合物的实测值与计算值吻合度比较高，但分子结构中含苯环、碳环和烷烃支链的有机化合物，实测值与计算值吻合度不是很高。建议FSG方程进一步考虑分子结构差异性的影响。

Measured values and analysis of molecular diffusion coefficient of organic vapor-air

The molecular diffusion coefficients of 21 types of volatile organic compounds found in air,including alkanes,cycloalkanes,arenes,and oxy-compounds (such as esters,alcohols,and ketones),were determined using a self-invented measurement device for the determination of gas diffusion coefficients. The results show that the diffusion coefficients decrease with the increase of either the length of the molecular chains or the boiling points of the syngeneic organic compounds under the same temperature. Furthermore,the diffusion coefficients for the organic isomers with branched chains are larger than those without the branched chain under the same temperature. The measured values were also compared with the values calculated from the Fuller,Schettler,and Giddings (FSG)equation and those reported in the literature. The results show that measured values and calculated values agree well for most organic compounds whether with single bonds and without ring structures,but there are some differences between the two values for organic compounds with benzene rings,carbon rings,and branched alkane chains. Therefore,the further improvement of the FSG equation based on the effects of the molecular structures of organic compounds is suggested.