Application of ionic liquids and microwave activation in selected organic reactions
1University of Oulu, Faculty of Science, Department of Chemistry
|Online Access:||PDF Full Text (PDF, 0.8 MB)|
|Persistent link:|| http://urn.fi/urn:isbn:9789514287190
|Publish Date:|| 2008-02-04
|Thesis type:||Doctoral Dissertation
|Defence Note:||Academic dissertation to be presented, with the assent of the Faculty of Science of the University of Oulu, for public defence in Kuusamonsali (Auditorium YB210), Linnanmaa, on February 13th, 2008, at 12 noon
Professor Liisa Kanerva
Professor Kristiina Wähälä
Ionic liquids and microwave heating have been studied in four different reactions namely esterifications, etherifications and ene and sulfonylation reactions. These techniques revealed several advantages over conventional methods.
In esterification of alcohols with anhydrides in ionic liquid solvents, the low boiling acid by-product could be removed before product recovery. The acid by-product could be regenerated back to the anhydride. Similar or higher yields were observed from esterifications with acetic anhydride of carbohydrates than with conventional methods. Even cellulose and starch could be esterificated in ionic liquids in the homogenous phase.
The etherification reaction in ionic liquid was challenging, due to the basic reaction conditions needed. 1-Methyl-3-butylimidazolium -cations ([BMIM]) could not be used in basic conditions. The new information was that [BMIM]-cation could not be used with epichlorohydrin.
The ene reaction was carried out with microwave heating in various solvents. Ionic liquids could be used as a solvent, but the ene reaction between allyl benzene. The best results were obtained without additional solvent. The yields by using microwave heating were high and reaction times were relatively short.
The sulfonylation reaction of aromatics could be catalyzed by metal bistriflimide complexes. Even chlorobenzene could be sulfonylated when Bi-complex was used as a catalyst. Ionic liquids could be used as a solvent, but sulfonylations were best carried out without additional solvents.
Acta Universitatis Ouluensis. A, Scientiae rerum naturalium
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