| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 150328 | Chemical Engineering Journal | 2012 | 7 Pages |
The role of catalyst acidity and porosity was studied for the isomerization of linoleic acid by testing two commercial Na-zeolites (mordenite and ZSM-5) and their acid modified forms (H+, Ni2+) obtained by cation exchange. Conversion of linoleic acid increased in the presence of higher amounts of weak-moderate acid centres (Brønsted and Lewis) together with a higher accessibility of the acid sites. Additionally, the synergic effect between Brønsted and Lewis centres led to higher selectivity to the isomer cis-9, trans-11-CLA whereas higher selectivity to trans-10, cis-12-CLA was achieved with higher amounts of Brønsted acidity. Interestingly, the use of microwaves for the Ni-exchange of Na-mordenite resulted in the formation of new weak Lewis acid centres, not observed for the rest of catalysts, yielding higher conversion, and higher selectivity to cis-9, trans-11-CLA than the sample conventionally exchanged.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Acidity strength and type, and porosity affected linoleic acid isomerization. ► Strong acid sites were responsible for faster catalyst deactivation. ► Use of microwaves for Ni-exchange of mordenite led to new active weak Lewis acid sites. ► Higher selectivity to c9, t11-CLA associated to synergy of Brønsted and Lewis acid sites. ► Higher selectivity to t10, c12-CLA attributed to higher amounts of Brønsted acidity.
