Solubilities of Copper(II) and Chromium(III) β-Diketonates in Supercritical Carbon Dioxide

Abstract

successfully modeled isotropically as a 1:1 disorder of a CO ligand and an H 2O ligand.After the Rh and P peaks, the next largest peak was located 5.5 Å from the Rh atom. This peak was situated in the center of three smaller peaks that formed a ca. 3-fold symmetric trigonal pyramid. Application of the crystal symmetry operations generated four symmetry-related peaks that, overall, formed a staggered ethane-like fragment that was assigned as an end-to-end disordered SO 3CF3 -moiety. Upon assigning the large peak as a S atom with a site-occupation factor ) 0.5, the largest peak in the subsequent difference map was located 0.96 Å from the S position and just off the vector between S and the position of its symmetry equivalent S(a). Overall, the pattern appeared to be the partially resolved superposition of the C atom (from the CF 3 group) and the S atom (of the SO 3 group). Therefore, the best approximation of the disordered SO 3CF3 -resulted from a model where both the S and C(2) atoms where given site-occupation factors of 0.5 and the F(1), F(2), and F(3) atoms were assigned site-occupation factors of 1.0 each in order to approximately account for both the superposition of the F and O atoms.Despite the disorder in the CO, H 2O, and SO3CF3 -positions, refinement of the structure to 10.57% was possible. The density of the crystals was determined to be 1.57(2) g/cm 3 by flotation in a CCl4/ hexane mixture. The calculated density for 4 molecules of trans-[Rh-(CO)(PPh 3)2(OH2)] [OTf] per unit cell is 1.57 g/cm 3 .

Effects of Solution Concentrations on Crystal Growth of Anthracene Thin Films on Silicon by Rapid Expansion of Supercritical Solutions (RESS) Using Carbon Dioxide

“…As shown in Figure 2, the calibration curve obtained using acetone and hexane indicated a linear relationship between the average absorbance and the concentrations, based on the Beer-Lambert law. The calibration curve was prepared using hexane because it has a polarity similar to that of supercritical carbon dioxide and has been shown to exhibit similar molar absorptivity (Hyatt, 1984;Lagalante et al, 1995;Rice et al, 1995;Carrott and Wai, 1998). The concentration of a prepared supercritical solution was determined by measuring the average absorbance defined by Eq.…”

Spectroscopy, modeling and computation of metal chelate solubility in supercritical CO{sub 2}

“…Essentially all previous modeling of metal chelate solubilities in supercritical COZ had been done with Regular Solution Theory (Lagalante et al, 1995;Wai et af., 1996). The main advantages of this model are that for solutions of components that are all liquids at the temperature of interest, the only information needed to predict the phase behavior is each components' liquid molar volume, v~, and volubility parameter, & The volubility parameter is defined as (AU/ v~)in, where AU is the internal energy of vaporization.…”

Spectroscopy, modeling and computation of metal chelate solubility in supercritical CO{sub 2}. Annual progress report, September 15, 1996--September 14, 1997

“…A limited number of solubility measurements are available in the literature for metal chelate complexes in supercritical CO 2 (Laintz et al, 1991;Wai et al, 1993a,b: Lin et al, 1995aWai and Smart, 1996;Lagalante et al, 1995;Sievers et al, 1996;Ashraf-Khorassani et al, 1996;M'Hamdi et al, 1991;Saito et al, 1990). To complement these measurements we have assembled a supercritical CO 2 extraction unit consisting, of an ISCO Model 260D syringe pump and SFX supercritical fluid extractor.…”