ISSN:
1573-1111
Keywords:
Tetrahydrofuran clathrate hydrate
;
high pressure
;
phase transition
;
structure II clathrate hydrate
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract A high-pressure phase of the clathrate hydrate of tetrahydrofuran was prepared by freezing a liquid phase of overall composition THF · 7 H2O under a pressure of 3.0 kbar, or by pressurizing the solid structure II THF hydrate of 255K to 3.4 kbar. Unfortunately, the products recovered at 77K were always mixed phase materials as shown by X-ray powder diffraction. A number of diffraction lines could be indexed in terms of the cubic structure I hydrate with a slightly expanded lattice parameter, 12.08 Å, giving some support to Dyadin's idea that the high pressure phase transition involves a conversion of Structure II to Structure I. Other phases observed in the recovered product include Ice IX and amorphous materials. The reversion of the high pressure sample to the structure II hydrate was followed by differential scanning calorimetry. At ambient pressure, the high pressure sample converts slowly back to Structure II hydrate event at 77K.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00708783
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