Liquid and supercritical carbon dioxide as organic solvents

Abstract

It has been pointed out that nucleofugality in 1,2-elimination reactions has been little studied.20,21 This is because it is difficult to separate unambiguously deprotonation from departure of the leaving group.20 In the present study, these processes have been separated in the few

Controlled/living heterogeneous radical polymerization in supercritical carbon dioxide

“…47 However, liquid CO 2 and scCO 2 can dissolve most nonpolar and also many polar low MW compounds. 36,48,49 The CO 2 molecule has zero permanent dipole moment, 50 but has been reported to be marginally nonlinear (thus having a weak dipole moment) in the supercritical state. 51 Despite its zero (or close to zero in scCO 2 ) dipole moment and low dielectric constant, scCO 2 cannot be considered a nonpolar solvent comparable to alkanes.…”

Fundamental Studies and Applications of Supercritical Fluids

“…The majority of the reports on supercritical fluid solvation have used steady-state solvatochromic absorbance measurements (21)(22)(23)(24)(25)(26)(27)(28). The original aim of these experiments was to determine the solvating power of supercritical fluids for chromatography and extraction (SFC and SFE) (26,28).…”

“…Initial supercritical fluid work was on C0 2 (21)(22)(23) and indicated weak interactions between the fluid and solute. Additional work has appeared on Xe, SF 6 , C^, and NH 3 (24,25).…”

“…Steady-state solvatochromic techniques provide a reasonable means to study solvation processes in supercritical media (5,(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(43)(44)(45)(59)(60)(61)(62)(63)(64)(65)(66)(67)(68). But, unless the interaction rates between the solute species and the supercritical fluid are slow, these "static" methods cannot be used to study solvation kinetics.…”

“…Some of these efforts have used optical spectroscopy (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(43)(44)(45) and others have used chromatographic methods as a tool to probe the aforementioned interactions. Many of these experimental studies have been advanced by theoretical calculations and modelling (35-42).…”