Probing the phase transition behavior of acetonitrile confined in mesoporous silica by FT Raman spectroscopy
Article first published online: 11 FEB 2011
Copyright © 2011 John Wiley & Sons, Ltd.
Journal of Raman Spectroscopy
Volume 42, Issue 6, pages 1396–1404, June 2011
How to Cite
Li, D. and Huang, Y. (2011), Probing the phase transition behavior of acetonitrile confined in mesoporous silica by FT Raman spectroscopy. J. Raman Spectrosc., 42: 1396–1404. doi: 10.1002/jrs.2866
- Issue published online: 17 JUN 2011
- Article first published online: 11 FEB 2011
- Manuscript Accepted: 8 NOV 2010
- Manuscript Received: 3 SEP 2010
- NSERC of Canada
- phase transition;
- FT Raman;
- mesoporous silica;
Phase transitions of acetonitrile confined in mesoporous silica SBA-15 and mesocellular silica foam (MCF) having different pore diameters of 39.0, 39.9, 28.4, 8.7, and 4.6 nm with corresponding pore openings of 20.9, 12.1, 10.0, 8.7, and 4.6 nm were investigated by FT Raman spectroscopy. Melting and freezing temperature depressions were found for acetonitrile confined in mesoporous silica with pore opening sizes of 20.9, 12.1, 10.0 and 8.7 nm. A thermal hysteresis between the cooling and heating cycles was also observed. It appears that the smaller the pore opening, the larger the depression of melting or freezing temperature. Although two solid ( and ) phases exist in bulk acetonitrile, only the liquid β phase transition was detected for acetonitrile confined in the nanopores of mesoporous silica. The solid-to-solid phase transition was not observed. For the mesoporous silica with the smallest pore size of 4.6 nm, neither the liquid nor the transition was observed for the confined acetonitrile. The results demonstrate that FT Raman spectroscopy is a useful technique for studying the phase transition behavior of organic compounds confined in silica-based hosts. Copyright © 2011 John Wiley & Sons, Ltd.