Quadrupolar Solvent Effects on Solvation and Reactivity of Solutes Dissolved in Supercritical CO₂

Abstract

This article presents an overview of our recent studies of solvation and unimolecular reactivity in liquids and supercritical fluids. We review our research on rotational diffusion and photoisomerization kinetics of diphenylpolyenes in polar liquids and supercritical fluids. These results provide a qualitative demonstration of the influence of solvent quadrupole-solute dipole interactions on chemical reactivity in supercritical CO 2 . The CO 2 quadrupole moment both increases solvent-solute friction experienced by a dipolar diphenylpolyene solute molecule and diminishes the activation barrier of the isomerization reaction via interaction with the polar transition state. We also review our recent studies of quadrupolar solvation and excited-state excimer formation kinetics of ADMA (1-[9-anthryl]-3-[4-N,N-dimethylaniline] propane). The ADMA studies have yielded quantitative confirmation of the importance of quadrupolar solvent-dipolar solute interactions in solvation and reactivity in supercritical CO 2 . The results of these studies allow us to measure the contribution of solvent quadrupole-solute dipole interaction to the solvation energy of the excited-state charge transfer form of ADMA. We also discuss recent evidence indicating that the CO 2 quadrupole moment influences the kinetics of the charge-transfer reaction.

Determining noble gas partitioning within a CO2–H2O system at elevated temperatures and pressures

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Poly(amide-12-b-ethylene oxide)/glycerol triacetate blend membranes for CO2 separation

“…Therefore, in order to improve CO 2 permeation performance, some new rubbery polymers, which usually contain CO 2 -philic groups, such as carbonyl, ether, acetate groups, have been developed as membrane materials recently aiming to increase CO 2 solubility and CO 2 solubility selectivity. Generally, CO 2 -philic groups are classified as hard bases by Pearson's hard and soft acid-base principles (Pearson, 1963(Pearson, , 1968, and they can interact with the hard acid CO 2 which has a large quadrupole moment (Kauffman, 2001). As is known, the solubility of penetrant gas mainly depends on gas physical properties (condensability) and its interactions with the polymer matrix.…”

Controlled/living heterogeneous radical polymerization in supercritical carbon dioxide

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