Study on the infinite dilution activity coefficients of binary systems containing ethers, alkanols and alkanes

分离过程的精确设计需要了解相平衡行为。汽液平衡的关联或预测通常可用液相活度系数进行。在这项研究中，无限稀释活度系数的实验测量报告的二元系统包含醚，烷醇和烷烃。醚是令人感兴趣的，因为醚，如甲基叔丁基醚（MTBE），已被要求提高烷烃的燃烧效率。在这项研究中，醚的无限稀释活度系数（二乙醚、甲基叔丁基醚和二异丙基醚）（辛烷、十二烷和十六烷）或烷醇在283.15- 313.15K范围内，用气提法测定了正辛醇、正癸醇和正十二醇的ASOG值，并与实验结果进行了比较将广泛应用于预测溶液液相活度系数的群解析解（Analytical Solution Of Groups）应用于无限稀释活度系数的关联。利用正构烷烃二元混合物的无限稀释活度系数数据，对Flory-Huggins（FH）部分进行了检验，并提出了修正正构烷烃碳数的经验公式。改进了基团相互作用（G）部分，将基团数与接触概率相结合，使1-和2-烷醇在烷烃中的无限稀释活度系数，以及醚在烷烃或烷醇中的无限稀释活度系数得到了较好的关联。

The accurate design of separation process requires the knowledge of phase equilibrium behavior. The correlation or prediction of vapor-liquid equilibria (VLE) can be usually performed by using activity coefficients for liquid phase. In this study, experimental measurements of infinite dilution activity coefficients were reported for binary systems containing ethers, alkanols and alkanes. Ethers are of interest since ether, such as methyl tertial butyl ether (MTBE), has been claimed to improve the combustion efficiency of alkane. In this study, the infinite dilution activity coefficients of ethers (diethy1 ether, MTBE and diisopropy1 ether) in alkanes (octane, dodecane and hexadecane) or alkanols (octanol, decanol and dodecanol) were measured in the region of 283.15-313.15 K by using the gas stripping method.The ASOG (Analytical Solution Of Groups), which is widely applied to predict the liquid-phase activity coefficients of solutions, was applied to correlate the infinite dilution activity coefficients. In this study, the Flory-Huggins (FH) part was examined by using the infinite dilution activity coefficient data of n-alkane binary mixtures and an empirical equation is proposed to modify the number of carbons contained in the n-alkanes. The group-interaction (G) part was improved by using the number of group with the contact probability to give a good correlation for the infinite dilution activity coefficients of 1- and 2- alkanols in alkanes, and ethers in alkanes or alkanols.