Transport and relaxation processes in supercritical fluids. Technical progress report

Technical Report · Wed Jan 01 00:00:00 EST 1986

OSTI ID:5631374

Jonas, J

We have tested our improved NMR method for determining diffusion coefficients using a sample of H/sub 2/O. We obtain the literature value for D to within the error of the experiment (+- 3%). A manuscript on the method is in preparation. This NMR diffusion experiment now allows us to obtain diffusion data for the naphthalene-CO/sub 2/ system. Spin echo modulation is no longer a problem, so we may monitor the proton NMR signal from naphthalene which has the necessary sensitivity to obtain diffusion data. Diffusion measurements are now in progress. These are the first NMR diffusion measurements on a solid-supercritical fluid system. We have recently been testing the feasibility of obtaining high resolution sulfur-33 NMR spectra of solids containing sulfur dissolved in supercritical fluids. Typically sulfur linewidths in these molecules are very large (greater than 10kHz) when dissolved in liquid solution. However, the viscosity of a supercritical fluid is much less than that of a simple liquid, and thus a sulfur containing compound dissolved in a supercritical fluid should have a greatly narrowed linewidth. This would allow the characterization of sulfur containing coal liquids, for example. We have investigated the system dibenzothiophene-supercritical ethylene in this way. Unfortunately, the NMR sensitivity of /sup 33/S is quite poor, and the signal to noise ratios were not sufficient to obtain the spectrum. We now plan to use the supercritical solvent xenon, which is known to be an excellent solvent. This solvent should give greater solubilities so that the problems of sensitivity can be overcome.

• Research Organization: Illinois Univ., Urbana (USA). Dept. of Chemistry
• DOE Contract Number: FG22-85PC80503
• OSTI ID: 5631374
• Report Number(s): DOE/PC/80503-T1; ON: DE86007847
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBON DIOXIDE
SUPERCRITICAL STATE
DEUTERIUM
DIFFUSION
ETHYLENE
NAPHTHALENE
SULFUR 33
WATER
XENON
NUCLEAR MAGNETIC RESONANCE
ALKENES
AROMATICS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CONDENSED AROMATICS
ELEMENTS
EVEN-ODD NUCLEI
FLUIDS
GASES
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RARE GASES
RESONANCE
STABLE ISOTOPES
SULFUR ISOTOPES
400201* - Chemical & Physicochemical Properties