Application of solvatochromic probes to supercritical and mixed fluid solvents
Changes of the polarity/polarizability of supercritical CO/sub 2/, N/sub 2/O, Freon-13, NH/sub 3/, and CO/sub 2//methanol mixtures, were measured by observing the shift of the uv absorption of 2-nitroanisole as a function of temperature and pressure. The polarities of the supercritical fluid solvents are compared to those of liquid solvents through use of the Kamlet-Taft ..pi..* polarity scale. In the pure fluid solvents the polarity was found to be correlated primarily with density. The data for CO/sub 2/ indicate that a change in the cybotatic region occurs at a fluid density of approx.0.3 gm/cm/sup 3/. Adding methanol as a modifer to supercritical CO/sub 2/ gradually increases the polarity of the solvent; in solutions with over 10% methanol the composition of the cybotatic region appears to differ from the bulk composition, being enriched in methanol. 25 refs., 7 figs., 2 tabs.
- Research Organization:
- Pacific Northwest Lab., Richland, WA (USA)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 6142411
- Report Number(s):
- PNL-SA-12935; CONF-850942-47; ON: DE86004876
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ABSORPTION SPECTRA
ALCOHOLS
AMMONIA
ANISOLE
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
DATA
DENSITY
ELECTRICAL PROPERTIES
ETHERS
EXPERIMENTAL DATA
FREONS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDRIDES
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
METHANOL
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NITROGEN OXIDES
NITROUS OXIDE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POLARIZABILITY
PRESSURE EFFECTS
SOLVENT PROPERTIES
SPECTRA
TEMPERATURE EFFECTS