【摘要】 采用脉冲色谱法测定了140℃时疏水多孔硅胶(HPS)上C2～5醇的吸附等温线及醇和水的Henry常数。分析得出,C2～5醇的吸附等温线在醇分压小于2.5kPa时符合Freundlich模型,醇分压小于0.3kPa时符合Langmuir单分子层模型,C2～5直链醇的Henry常数随醇的沸点和碳原子数的增加呈指数性递增,支链醇与HPS表面的作用力更强;醇的Henry常数可以分解为—CH3,—CH2—,—OH基团贡献值的加和,其对数值分别为0.68,0.60,0.46,-11.42;在气相条件下,因HPS的疏水性而使水分子不易接近HPS表面;HPS对醇-醇物系的分离是由于HPS具有基团选择性的特性。更多还原

【Abstract】 To illustrate interaction between hydrophobic porous silica(HPS) and water and alcohols,Henry constant of water and adsorption isotherms of C2-5 alcohols were investigated by mass of finite pulse gas-solid chromatography at 140 ℃.It was found that adsorption isotherms of C2-5 alcohols could be accurately correlated by Freundlich model at partial pressure below 2.5 kPa and conformed to Langmuir model at partial pressure below 0.3 kPa.All Henry constants of alcohols could be divided into four groups of —CH3,—CH2—,and —OH,with logarithm values of 0.68,0.60,0.46 and-11.42 correspondingly.The Henry constants of n-alcohols increased exponentially with their carbon number and boiling points,and the branched alcohols are adsorbed more strongly on surface of HPS.In gaseous phase water molecule contacts the surface of this material with more difficulties due to the existence of superficial CH3 groups.It seems that the material featured group selectivity to different alcohols.更多还原