摘要
考察了KA、NaA、CaA及NaX沸石填充的聚乙烯醇膜在不同醇/水体系中的分离性能,发现经沸石填充后膜的通量增加,而分离系数的升降则取决于被分离醇分子及沸石的孔径大小。对于小分子醇/水体系,填充膜分离系数下降,反之则上升。经考察KA填充膜对乙酸乙酯化和水杨酸甲酯化的膜助催化反应发现,填充膜对反应的推动作用较未改性膜有了进一步的提高。
The composite membrane consisting of zeolites KA,NaA,CaA or NaX and poly vinyl alcohol polymer were prepared. The pervaporation and separation characteristics of different alcohol-water systems through these membranes were investigated at temperatures ranging from 20℃ to 50℃- Distinct improvement on molecular transport and the molacular sieving effect of the zeolites have been observed. The addition of zeolite filler to PVA membrane appears to improve the flux of the membrane in various alcohol/water systems. The order of the increment of flux is. NaX>CaA>NaA>KA, which runs parallel to the increase in pore size of the zeolites. The separation factor of the zeolite-filled membranes can be increased or decreased depending on the kind of zeolite filled and the size of the alcohol molecule. For CH3OH/HZO and C2H5OH/H2O systems, at a higher temperature the flux of the KA filled membrane is improved, while its separation factor remains unchanged. Hence the performance of KA filled membrane in the separation of CH3OH and C2H5OH from aqueous mixtures is better than that of the unfilled PVA membrane. The esterification of acetic acid by ethanol is aided by the KA membrane, and the time required to attain 95% conversion is reduced by 9 h as compared with the unfilled PVA membrane. For the esterification of salicylic acid by methanol, the addition of KA into the membrane increases the reaction conversion by 1. 2 times as well.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
1993年第4期559-562,共4页
Chemical Journal of Chinese Universities
关键词
聚乙烯醇膜
沸石填充膜
醇水分离
Poly vinyl alcohol pervaporation membrane, Zeolite-filled membrane, Aicohol/water separation, Catalytic esterification
