Resolution of a nonionic surfactant oligomeric mixture by means of DOSY with inverse micelle assistance
Copyright © 2011 John Wiley & Sons, Ltd.
| Publié dans: | Magnetic resonance in chemistry : MRC. - 1985. - 49(2011), 4 vom: 30. Apr., Seite 195-8 |
|---|---|
| Auteur principal: | |
| Autres auteurs: | |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2011
|
| Accès à la collection: | Magnetic resonance in chemistry : MRC |
| Sujets: | Journal Article Research Support, Non-U.S. Gov't Micelles Surface-Active Agents Ethylene Oxide JJH7GNN18P |
| Résumé: | Copyright © 2011 John Wiley & Sons, Ltd. DOSY is a recognized, efficient technique in the analysis of mixtures. It relies on the differences in self-diffusion coefficients, which are determined by the molecular size. Nowadays, efforts are directed towards devising matrices able to interact with the components of the mixture with differential affinity, and therefore capable to interfere with the diffusion processes and to display resolving power towards species of close, or even equal molecular weight, like isomers. Usually, commercial nonionic surfactants are mixtures of oligomeric species, since the head group, which is a short polyoxyehtylene chain, is somewhat polydisperse. The embedment of Igepal CA-520, 5 polyoxyethylene iso-octylphenyl ether, in an inverse microemulsion led to the separation of (1)H signals of the various oligomeric components. This ensued from the differential partitioning between the oil and the surface of the inverse micelles, which depends on the ethyleneoxide number (EON) of the head groups. Thus, it was possible to ascertain that the length distribution of the polyethyleneoxide chains is ingood agreement with the Poisson distribution theoretically predicted for the polymerization of ethylene oxide. The DOSY spectrum contributed to the assignment of the signals and afforded the partition degree, between the two environments, for each individual oligomeric species, providing further insight into nonionic inverse microemulsions, at present widely employed reaction media in the nanotechnological syntheses |
|---|---|
| Description: | Date Completed 01.08.2011 Date Revised 21.11.2013 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1097-458X |
| DOI: | 10.1002/mrc.2732 |