Controlled desilylation of cellulose with stoichiometric amounts of water in the presence of ammonia

Mörmann, Werner; Demeter, Jürgen

doi:10.1002/1521-3935(20001001)201:15<1963::aid-macp1963>3.0.co;2-k

Cited by 13 publications

(4 citation statements)

References 9 publications

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“…The desilylation of cellulose silyl ethers can lead to completely desilylated cellulose regenerates (films, particles, and filaments), to partially silylated celluloses with an alternative distribution of silyl groups,89b,c or to regioselectively substituted cellulose derivatives by using the protecting group technique 90. Typical examples are the syntheses of 3‐ and 2,3‐alkyl ethers of cellulose (Scheme and ).…”

Section: Cellulose Chemistry: New Syntheses Products and Supramolmentioning

confidence: 99%

Cellulose: Fascinating Biopolymer and Sustainable Raw Material

et al. 2005

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As the most important skeletal component in plants, the polysaccharide cellulose is an almost inexhaustible polymeric raw material with fascinating structure and properties. Formed by the repeated connection of D-glucose building blocks, the highly functionalized, linear stiff-chain homopolymer is characterized by its hydrophilicity, chirality, biodegradability, broad chemical modifying capacity, and its formation of versatile semicrystalline fiber morphologies. In view of the considerable increase in interdisciplinary cellulose research and product development over the past decade worldwide, this paper assembles the current knowledge in the structure and chemistry of cellulose, and in the development of innovative cellulose esters and ethers for coatings, films, membranes, building materials, drilling techniques, pharmaceuticals, and foodstuffs. New frontiers, including environmentally friendly cellulose fiber technologies, bacterial cellulose biomaterials, and in-vitro syntheses of cellulose are highlighted together with future aims, strategies, and perspectives of cellulose research and its applications.

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Section: Cellulose Chemistry: New Syntheses Products and Supramolmentioning

confidence: 99%

Cellulose: Fascinating Biopolymer and Sustainable Raw Material

et al. 2005

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“…Durch Desilylierung der Cellulosesilylether entstehen entweder vollständig desilylierte Regenerat‐Cellulosen (Filme, Partikel, Fäden), partiell silylierte Cellulosen mit alternativer Verteilung der Silylgruppen89b,c oder regioselektiv aufgebaute Cellulosederivate bei Anwendung der Schutzgruppentechnik 90. Typische Beispiele sind die Synthese von 3‐ und 2,3‐Alkylethern der Cellulose (Schema und ).…”

Section: Cellulosechemie: Neue Synthesen Produkte Und Supramolekuunclassified

Cellulose: faszinierendes Biopolymer und nachhaltiger Rohstoff

et al. 2005

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Als wichtigster Gerüstbildner der Pflanzenwelt ist das Polysaccharid Cellulose ein nahezu unerschöpflicher polymerer Rohstoff mit einem faszinierenden Struktur‐ und Eigenschaftspotenzial. Durch reguläre Verknüpfung von D‐Glucose‐Bausteinen gebildet, zeichnet sich das hochfunktionalisierte lineare und kettensteife Homopolymer Cellulose durch Hydrophilie, Chiralität, Bioabbaubarkeit, breite chemische Modifizierbarkeit und den Aufbau vielfältiger teilkristalliner Fasermorphologien aus. Mit Blick auf die weltweit stark expandierende interdisziplinäre Celluloseforschung und Produktentwicklung der letzten Dekade verknüpft dieser Aufsatz den aktuellen Wissensstand zu Struktur und Chemie der Cellulose mit der Entwicklung innovativer Celluloseester und ‐ether für Beschichtungen, Filme, Membranen, Baustoffe, Bohrtechnologien, Pharmaka und Nahrungsmittel. Mit umweltfreundlichen Cellulosefaser‐Technologien, Bakteriencellulose‐Biomaterialien und In‐vitro‐Synthesen der Cellulose sind Wege ins Neuland einbezogen, ebenso Aussagen zu den weiteren Zielen, Strategien und Perspektiven der Celluloseforschung und ‐applikation.

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“…Complete silylation of linear polysaccharides such as amylose, pullulan, or cellulose − were reported. However, to the best of our knowledge, complete silylation of lowly branched polysaccharides such as dextran has not been reported until recently.…”

Section: Introductionmentioning

confidence: 99%

Silylation Reaction of Dextran: Effect of Experimental Conditions on Silylation Yield, Regioselectivity, and Chemical Stability of Silylated Dextrans

et al. 2003

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The controlled synthesis of biodegradable copolymers of dextran grafted with aliphatic polyesters first requires the preparation of polysaccharide derivatives soluble in organic solvents. Silylation of dextran can thus lead to such organosoluble derivatives and allows the polymerization of cyclic esters initiated from the nonsilylated OH functions. Silylation of dextran was studied in DMSO by different reactants such as 1,1,1,3,3,3-hexamethyldisilazane (HMDS) in the presence of various catalysts and N,O-bis(trimethylsilyl)acetamide (BSA). According to the silylating agent and the used experimental conditions, it was possible to obtain highly or totally silylated dextrans. In parallel, an investigation of the chemical stability of the dextran chain during silylation was performed. Thus, it was found that, when used at 50 degrees C, HMDS with or without catalysts gives a relatively high silylation yield and does not alter the dextran chain length, whereas at 80 degrees C, dextran degradation was observed. BSA is a very good silylating agent, which allows reaching 100% silylation even at 50 degrees C but provokes the degradation of the polysaccharide chains. The work was completed by a study of the reactivity order of the glucosidic OH functions toward silylation reaction. This order was found to be (OH(2) > OH(4) > OH(3)) as already reported for other reactions. 2D-NMR of highly silylated dextrans demonstrated that they are constituted of both quantitatively silylated glucose units and two types of disilylated ones.

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Controlled desilylation of cellulose with stoichiometric amounts of water in the presence of ammonia

Cited by 13 publications

References 9 publications

Cellulose: Fascinating Biopolymer and Sustainable Raw Material

Cellulose: Fascinating Biopolymer and Sustainable Raw Material

Cellulose: faszinierendes Biopolymer und nachhaltiger Rohstoff

Silylation Reaction of Dextran: Effect of Experimental Conditions on Silylation Yield, Regioselectivity, and Chemical Stability of Silylated Dextrans

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