醚化β-环糊精的制备及其混合膜对二甲苯异构体的选择性

采用WilliamSon合成法使氯化苄(PhCH2Cl)与β-环糊精(β-CD)进行醚化反应.红外光谱表明,所得产物为醚化β-CD.根据元素分析结果,计算出各反应的取代度和转化率.系统地考察了反应条件对转化率和取代度的影响.此外,考察了醚化β-CD与聚乙烯醇缩丁醛(PVB)共混膜对含10%对二甲苯的对/间二甲苯混合液的渗透气化性能的影响.结果显示,30℃时,共混膜的分离因子α可达1.16,而对二甲苯PX的渗透通量J高达70.57g/(m2·h).

Preparation of Etherified β-Cyclodextrin and Selectivity in Its Blend Membrane for Xylene Isomers

Etherified β-CD was synthesized bYUsing benzyl chloride(PhCH22Cl).The influences of etherification conditions on the reaction conversion and the degree of substitution of etherified β-CD were investigated. The reaction conversion increases with increasing molar ratio of PhCH22Cl to β-CD and the concentration of β-CD. The most proper temperature and time for the reaction conversion are 90 ℃ and 12 h, respectively. The degree of substitution of etherified β-CD increases greatly with increasing molar ratio of PhCH22Cl to β-CD, but there is no significant change for the degree of substitution when temperature, time and concentration of β-CD increased. Meanwhile, the pervaporation performance of PVB membrane containing 25%(mass fraction) etherified β-CD for 10%(mass fraction) PX in PM/MX mixture were measured, and the separation factor α=1.16, permeation flux J=70.57 g/(m2·h) at 30 ℃ were obtained.