Interactions of ionic liquids with polysaccharides 1.pdf

CommunicationInteractions of Ionic Liquids with Polysaccharides 1. Unexpected Acetylation of Cellulose with 1-Ethyl-3-methylimidazolium AcetateSarah Ko?hler, Tim Liebert, Michael Scho?bitz, Jens Schaller, Frank Meister, Wolfgang Gu?nther, Thomas Heinze*The homogeneous conversion of cellulose in the ionic liquid 1-ethyl-3-methylimidazolium acetatewith 2-furoyl chloride, p-toluenesulfonyl chloride, and triphenylmethyl chloride yields surprisingly pure cellulose acetate samples in any case. From NMR spectroscopic studies, it may be concluded that during the homogeneous functionalization reactive intermediates includ- ing furane-2-carboxylic acid/acetic acid anhy- dride and acetic acid triphenylmethyl ester are formed leading to the cellulose acetates with DS values in the range from 0.55 to 1.86.Introduction Starting with the work of Rogers and coworkers the interest in organic salt melts as media for dissolution,S. Ko?hler, T. Liebert, M. Scho?bitz, T. Heinze Centre of Excellence for Polysaccharide Research at Friedrich Schiller University of Jena, Humboldtstra?e 10, 07743 Jena, Germany Fax: t49 3641 94 8272; E-mail: Thomas.Heinze@uni-jena.de M. Scho?bitz, J. Schaller, F. Meister, T. Heinze Thuringian Institute for Textile and Plastics Research, Breitscheidstra?e 97, 07407 Rudolstadt, Germany W. Gu?nther Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University of Jena, Humboldtstra?e 10, 07743 Jena, Germany Macromol. Rapid Commun. 2007, 28, 2311–2317
2007 WILEY-VCH Verlag GmbH Co. KGaA, Weinheimregeneration, and chemical modification of cellulose was revived.[1] Although comparable systems were already investigated in the 1930s by Graenacher[2] and in the 1960s by Husemann and Siefert,[3] the new interest is fueled both by the experiences with solvents on the basis of reactive melts such as N-methylmorpholine-N-oxide[4] and by the commercial availability of a whole variety of such compounds now referred to as ionic liquids (ILs). D