Facilitated Olefin Transport by Reversible Olefin Coordination to Silver Ions in a Dry Cellulose Acetate Membrane
✍ Scribed by Jae Hee Ryu; Hyunjoo Lee; Yong Jin Kim; Yong Soo Kang; Hoon Sik Kim
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 105 KB
- Volume
- 7
- Category
- Article
- ISSN
- 0947-6539
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✦ Synopsis
The highly selective dry complex membrane AgBF 4 ± 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 AgBF 4 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 CAÐ two in the acetate group and one in the ether linkage. Upon incorporation of AgBF 4 into CA, the carbonyl stretching frequency of the free cellulose acetate at 1750 cm À1 shifts to a lower frequency by about 41 cm À1 . The binding energy cor-responding to a carbonyl oxygen atom in the O 1s XPS spectrum shifts to a more positive binding energy by the incorporation of AgBF 4 . Reversible olefin coordination to silver ions has been observed by FT-IR and UV studies. Treatment of the AgBF 4 ± 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.