Ryu J H, Lee H, Kim Y J, Kang Y S, Kim H S
Center for Facilitated Transport Membrane, Korea Institute of Science and Technology, Seoul.
Chemistry. 2001 Apr 1;7(7):1525-9. doi: 10.1002/1521-3765(20010401)7:7<1525::aid-chem1525>3.0.co;2-u.
The highly selective dry complex membrane AgBF4-cellulose acetate (CA) was prepared and tested for the separation of ethylene/ethane and propylene/propane mixtures. The maximum selectivity for olefin over paraffin was found to be 280 for the ethylene/ethane mixture and 200 for the propylene/propane mixture. Solid-state interactions of AgBF4 with cellulose acetate (CA) and/or olefins have been investigated by using FT-IR, UV, and X-ray photoelectron spectroscopy (XPS). FT-IR and XPS studies clearly show that the silver ions are coordinated by carbonyl oxygen atoms among three different types of oxygen atoms present in CA-two in the acetate group and one in the ether linkage. Upon incorporation of AgBF4 into CA, the carbonyl stretching frequency of the free cellulose acetate at 1750 cm(-1) shifts to a lower frequency by about 41 cm(-1). The binding energy corresponding to a carbonyl oxygen atom in the O 1s XPS spectrum shifts to a more positive binding energy by the incorporation of AgBF4. Reversible olefin coordination to silver ions has been observed by FT-IR and UV studies. Treatment of the AgBF4-CA membrane placed in a gas cell with propylene produces a propylene-coordinated membrane in which coordinated propylene is easily replaced by other olefins such as 1,3-butadiene.
制备了高选择性干复合膜AgBF₄-醋酸纤维素（CA），并对其用于乙烯/乙烷和丙烯/丙烷混合物的分离进行了测试。发现对于乙烯/乙烷混合物，烯烃对石蜡的最大选择性为280，对于丙烯/丙烷混合物为200。通过傅里叶变换红外光谱（FT-IR）、紫外光谱（UV）和X射线光电子能谱（XPS）研究了AgBF₄与醋酸纤维素（CA）和/或烯烃的固态相互作用。FT-IR和XPS研究清楚地表明，银离子由醋酸纤维素中存在的三种不同类型的氧原子中的羰基氧原子配位，其中两种在醋酸基团中，一种在醚键中。将AgBF₄掺入CA后，游离醋酸纤维素在1750 cm⁻¹处的羰基伸缩频率向较低频率移动约41 cm⁻¹。通过掺入AgBF₄，O 1s XPS光谱中对应于羰基氧原子的结合能向更正的结合能移动。通过FT-IR和UV研究观察到烯烃与银离子的可逆配位。用丙烯处理置于气室中的AgBF₄-CA膜会产生一种丙烯配位膜，其中配位的丙烯很容易被其他烯烃如1,3-丁二烯取代。
