| Titre : | Carbonyl groups in sulfonated styrene-divinylbenzene macroporous resins (2009) |
| Auteurs : | Muhammad Arif Malik, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Industrial & engineering chemistry research (Vol. 48 N° 15, Août 2009) |
| Article en page(s) : | pp. 6961–6965 |
| Note générale : | Chemical engineering |
| Langues : | Anglais |
| Tags : | Carbonyl groups Porous styrene− ; divinylbenzene copolymers Sulfonation |
| Résumé : | The generation of carbonyl groups during sulfonation of porous styrene−divinylbenzene copolymers is reported. The carbonyl groups and sulfonic acid groups were verified by infrared spectroscopy and quantified by acid−base titrations. A gradual change in sulfonation reaction conditions from 70 °C/30 min to 98 °C/60 min resulted in a gradual increase in sulfonic acid group concentration from ∼1.85 to ∼3.13 mol/kg and in the carboxylic acid group concentration from ∼0 to ∼0.34 mol/kg. Data on the swelling coefficients in water indicate a slight increase in cross-linking during sulfonation. Conversion of ethyl or residual vinyl groups to carboxylic acid groups, followed by conversion of some of the acid groups to cross-links through an acid-catalyzed acylation reaction, is proposed. The proposed reactions also explain the pH-dependent color change of the resins. Sulfonation of copolymers with varied cross-linkages further supports our assertion that, as the concentrations of ethyl and residual vinyl groups increase, the concentration of —COOH groups also increases and the resin color becomes darker. |
| En ligne : | http://pubs.acs.org/doi/abs/10.1021/ie900681n |
