Extraction of aromatic organic compounds by polyurethane foam

The mechanism of extraction of organic compounds by open-cell polyurethane foam has been investigated through a detailed study with simple aromatic compounds. Comparison with identical extractions into diethyl ether suggests that the basic extraction mechanism is an ether-like solvent extraction process. The addition of salt increases the extraction and changing the dielectric constant of the aqueous solution also affects the extraction. For organic compounds which have a group capable of hydrogen bonding, some additional factor appears to influence the extraction. This appears to be hydrogen bonding with the polyurethane foam; it is stronger with polyether foam and reduced by the presence of a strong intramolecular hydrogen-bonding group placed ortho to the hydrogen-bonding group. Thermodynamic studies support these conclusions.