Abstract
Per-acetylated cyclic hexa-, hepta-, and octa-saccharide, (α-cyclodextrin octadecaacetate, β-cyclodextrin heneiicosaacetate and γ-cyclodextrin tetracosaacetate, respectively) exhibit melting point reduction and high solubility in dense CO2. Two-phase boundaries of the CO2-acetylated sugar mixtures were determined for per-acetylated cyclodextrin concentrations of 2-30wt.%. The dew-point locus of the CO2 per-acetylated cyclodextrin binary systems shifted to higher pressures as the number of saccharides in the acetylated cyclodextrin increased. The CO2-solubility of per-acetylated cyclodextrins was comparable to oligomers of poly(vinyl acetate) (PVAc) (the most CO2 soluble non-fluorous vinyl homopolymer) that contained an equivalent number of acetate groups. This very high degree of miscibility implies that the acyl groups of the per-acetylated cyclodextrins were readily accessible for favorable Lewis acid:Lewis base interactions with CO2. Upon depressurization, each per-acetylated cyclodextrin formed rigid, brittle foams within the vessel as the boiling per-acetylated cyclodextrin-rich phase solidified during the removal of CO2.
Original language | English (US) |
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Pages (from-to) | 211-217 |
Number of pages | 7 |
Journal | Fluid Phase Equilibria |
Volume | 211 |
Issue number | 2 |
DOIs | |
State | Published - Sep 1 2003 |
Keywords
- Acetylated cyclodextrin
- CO-philes
- Cyclodextrin
- Supercritical carbon dioxide
ASJC Scopus subject areas
- General Chemical Engineering
- General Physics and Astronomy
- Physical and Theoretical Chemistry