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

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

采用 William Son合成法使氯化苄 (Ph CH2 Cl)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 1 0 %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 .1 6 ,而对二甲苯 PX的渗透通量 J高达 70 .5 7g/(m2 · h) .

Etherified β-CD was synthesized by using benzyl chloride(PhCH 2Cl).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 PhCH 2Cl 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 PhCH 2Cl 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/(m 2·h) at 30 ℃ were obtained.