Studies on the synthesis of 2,3-o-hydroxyalkyl ethers of cellulose.
Novel 2,3-O-hydroxyethyl- and 2,3-O-hydroxypropyl cellulose products were synthesized by heterogeneous etherification of 6-O-(4-monomethoxytrityl) cellulose (MMTC). Due to the very hydrophobic character of MMTC, the reaction was successful in the presence of anionic and non-ionic detergent in the reaction mixture yielding the 2,3-O-cellulose ethers with a molar degree of substitution (MS) varying between 0.25 and 2.00 after detritylation. The products were characterized by means of (1)H and (13)C NMR spectroscopy including two-dimensional methods. The 2,3-O-hydroxypropyl cellulose samples are soluble in water at a MS as low as 0.8. The spectroscopic studies showed that the unusual solubility results from a preferred substitution of hydroxy groups of the anhydroglucose unit while the newly formed hydroxy moieties are included in the reaction to a minor extent only. In contrast, conventionally synthesized hydroxypropyl cellulose is soluble in water starting at a MS of about 4.0 because of the formation of oxyethylene side chains. (13)C DEPT 135 NMR spectrum of 2,3-O-hydroxypropyl cellulose.
Schaller
Jens
J
Kompetenzzentrum Polysaccharidforschung, Friedrich-Schiller-Universität Jena, Humboldtstrasse 10, D-07743 Jena, Germany.
Heinze
Thomas
T
D001672:Biocompatible Materials; D002482:Cellulose / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*; D003902:Detergents / Q000494:pharmacology; D004987:Ethers / Q000737:chemistry*; D005030:Ethylenes / Q000737:chemistry; D005947:Glucose / Q000737:chemistry; D007477:Ions; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008956:Models, Chemical; D015233:Models, Statistical; D011108:Polymers / Q000737:chemistry; D013053:Spectrophotometry
D001672:Biocompatible Materials; D003902:Detergents; D004987:Ethers; D005030:Ethylenes; D007477:Ions; D046911:Macromolecular Substances; D011108:Polymers; D002482:Cellulose; C036216:ethylene; C008079:hydroxypropylcellulose; D005947:Glucose