http://www.mtdna.or.kr/neowiz/board/up_files/files_17/Chitin_Chitosan_polymers_chemistrySolubilityFiberFormation.pdf

Chitin and chitosan polymers: Chemistry, solubility and fiber formation

This review gives a survey on the latest most representative developments and progress concerning ionic liquids, from their fundamental properties to their applications in catalytic processes. It also highlights their emerging use for biomass treatment and transformation.

Ionic liquids and catalysis: Recent progress from knowledge to applications

Lignocellulosic biomass is a plentiful and renewable resource for fuels and chemicals. Despite this potential, nearly all renewable fuels and chemicals are now produced from edible resources, such as starch, sugars, and oils; the challenges imposed by notoriously recalcitrant and heterogeneous lignocellulosic feedstocks have made their production from nonfood biomass inefficient and uneconomical. Here, we report that N,N-dimethylacetamide (DMA) containing lithium chloride (LiCl) is a privileged solvent that enables the synthesis of the renewable platform chemical 5-hydroxymethylfurfural (HMF) in a single step and unprecedented yield from untreated lignocellulosic biomass, as well as from purified cellulose, glucose, and fructose. The conversion of cellulose into HMF is unabated by the presence of other biomass components, such as lignin and protein. Mechanistic analyses reveal that loosely ion-paired halide ions in DMA−LiCl are critical for the remarkable rapidity (1−5 h) and yield (up to 92%) of this low...

http://pubs.acs.org/doi/pdf/10.1021/ja808537j

Simple Chemical Transformation of Lignocellulosic Biomass into Furans for Fuels and Chemicals

https://pubs.rsc.org/en/Content/ArticlePDF/2013/GC/C2GC36364J

Deconstruction of lignocellulosic biomass with ionic liquids

Sustainability, industrial ecology, eco-efficiency, and green chemistry are directing the development of the next generation of materials, products, and processes. Biodegradable plastics and biocompatible composites generated from renewable biomass feedstock are regarded as promising materials that could replace synthetic polymers and reduce global dependence on fossil fuel sources.1 It is estimated that the world is currently consuming petroleum at a rate 100 000 times faster than nature can replace it.2 The growing global environmental awareness and societal concern, high rate of depletion of petroleum resources, concepts of sustainability, and new environmental regulations have triggered the search for new products and processes that are more compatible with the environment. The most abundant natural polymer in our environment is cellulose. It has an estimated annual biosphere production of 90 × 109 metric tons and, consequently, represents the most obvious renewable resource for producing biocomposites.3 Its highly ordered structure is responsible for its desirable mechanical properties but makes it a challenge to find suitable solvents for its dissolution.4 The first attempts to dissolve cellulose date back to the early 1920s.5 Several aqueous and nonaqueous cellulose solvents have been discovered since then, but all of these solvents suffer either from high environmental toxicity or from insufficient solvation power.6 In general, the traditional cellulose dissolution processes require relatively harsh conditions and the use of expensive and uncommon solvents, which usually cannot be recovered after the process.6-10 However, a new class of solvents was opened to the cellulose research community, when in 2002 Swatloski et al. reported the use of an ionic liquid as solvent for cellulose both for the regeneration of cellulose and for the chemical modification of the polysaccharide.7 In 1934, Graenacher had discovered a solvent system with the ability to dissolve cellulose, but this was thought to be of little practical value at the time.11,12 Ionic liquids are a group of salts that exist as liquids at relatively low temperatures (<100 °C). They have many attractive properties, including chemical and thermal stability, nonflammability, and immeasurably low vapor pressure.12 First discovered in 1914 by Walden, their huge potential in industry and research was only realized within the last few decades.13,14 This review aims to provide a summary of our current state of knowledge on the structural features of wood * To whom correspondence should be addressed. E-mail: ken.marsh@ canterbury.ac.nz. Tel.: +64 3364 2140. Fax: +64 3364 2063. † Department of Chemical and Process Engineering. ‡ Department of Mechanical Engineering. Andre Pinkert was born in Schwabach, Germany, in 1981. He studied Chemistry at the University of Erlangen-Nurnberg, Germany, and received his prediploma and diploma degrees in 2004 and 2008, respectively. During 2005, he joined the Marine Natural Products Group, lead by Murray H. Munro and John W. Blunt, at the University of Canterbury (UoC), New Zealand, working on the isolation and characterization of bioactive metabolites. In early 2006, he returned to Germany and resumed his studies at the University of Erlangen-Nurnberg, finishing his degree under the supervision of Rudi van Eldik. Associated with his studies, during 2007, he worked for AREVA NP on radio-nuclear chemistry and computer modeling. Since 2008, he is studying towards a Ph.D. degree at UoC under the supervision of Shusheng Pang, Ken Marsh, and Mark Staiger. His research focuses on biocomposites from natural fibers, processed via ionic liquids. Chem. Rev. 2009, 109, 6712–6728 6712

Ionic Liquids and Their Interaction with Cellulose

Applications of ionic liquids in carbohydrate chemistry: a window of opportunities.

Bacterial cellulose (BC), a unique type of cellulose, with high degree of polymerization of 6 500 could be dissolved easily in the ionic liquid 1-N-butyl-3-methylimidazolium chloride. For the first time, well-soluble BC acetates and carbanilates of high degree of substitution (up to a complete modification of all hydroxyl groups) were accessible under homogeneous and mild reaction conditions. Characterization of the new BC derivatives by NMR and FTIR spectroscopy shows an unexpected distribution of the acetyl moieties in the order 0-6 > 0-3 > 0-2.

Efficient Homogeneous Chemical Modification of Bacterial Cellulose in the Ionic Liquid 1‐N‐Butyl‐3‐methylimidazolium Chloride

Some general comments about ionic liquids (ILs) and carbohydrates are given. The main scope of the review is to discuss the present state of the art of chemical modification of cellulose applying IL as reaction media considering own research results. ILs, namely i-butyl-3-methylimidazolium chloride (BMIMCl), 1-ethyl-3-methylimidazolium chloride (EMIMCI), 1-butyl-2,3-dimethylimidazolium chloride (BDMIMCI), 1-allyl-2,3-dimethylimidazolium bromide (ADMIMBr) and 1-ethyl-3-methylimidazolium acetate (EMIMAc) are solvents for cellulose (even for high molecular bacterial synthesized cellulose) and can easily be applied as reaction media for cellulose modification. We investigated the homogeneous acylation, carbanilation and silylation of the biopolymer cellulose. Under mild conditions and within short reaction time at low temperature (65 C to 80 °C) and low excess of reagent, various cellulose esters and carbanilates, dendronized cellulose and trimethylsilyl cellulose were obtained. The DS of the cellulose derivatives can be controlled by varying the reaction time, reaction temperature and the IL used as reaction medium.

Interactions of Ionic Liquids with Polysaccharides -2: Cellulose

Ionic liquids (ILs) are composed only of ions. Of special interest to this review are those where at least one ion (the cation) is organic and whose melting points are below or not far above room temperature. ILs are designated as "green" solvents because they have extremely low vapor pressure, are non-inflammable, and thermally and chemically stable. Therefore, many of them can be, in principle, recycled into the process indefinitely. The objective of the present review is to discuss different aspects of the use of ILs in carbohydrate chemistry, in particular, dissolution and functionalization of simple sugars, cyclodextrins, cellulose, starch, and chitin/chitosan. The molecular structure and synthesis of ILs most frequently employed in carbohydrate chemistry are discussed with an emphasis on imidazolium and pyridinium cations with different counterions. The physicochemical properties of ILs that are relevant to the dissolution and functionalization of carbohydrates, in particular their polarities and hydrogen-bonding abilities, are discussed. Dissolution of simple saccharides and biopolymers in ILs is presented with an emphasis on the mechanism of carbohydrate--IL interactions. Finally, the very interesting novel applications of the solutions obtained are addressed. These include, inter alia, spinning of the dissolved biopolymer into fibers, extrusion into slabs and rods, formation of matrixes for a myriad of substrates, including biomacromolecules, formation of nanocomposites, and functionalization to produce important derivatives. The use of ILs in many branches of science is expanding fast; it is hoped that this review will draw the attention of researchers to the "window of opportunities" that these green solvents open into carbohydrate chemistry.

Applications of Ionic Liquids in Carbohydrate Chemistry: A Window of Opportunities

The thermal behavior of cellulose dissolved in ionic liquids was studied in comparison to NMMO solutions. The cellulose solutions were characterized by reaction calorimetry and UV-vis spectroscopy. Generation of chromophoric substances in cellulose/IL solutions is minimized by exposing to temperatures of above 100 °C for longer time periods. Dynamic calorimetric investigations revealed first thermal activities above 180 °C applying EMIMac and above 200 °C for BMIMCl and five other ILs tested. Moreover, even in the case of modified cellulose/IL solutions, e.g., activated charcoal, only a slight decline of onset temperatures was registered compared to modified cellulose/NMMO solutions.

Susann Dorn

Papers

Applications of ionic liquids in carbohydrate chemistry: a window of opportunities.

Efficient Homogeneous Chemical Modification of Bacterial Cellulose in the Ionic Liquid 1‐N‐Butyl‐3‐methylimidazolium Chloride

Interactions of Ionic Liquids with Polysaccharides -2: Cellulose

Applications of Ionic Liquids in Carbohydrate Chemistry: A Window of Opportunities

Interactions of Ionic Liquids with Polysaccharides – 7: Thermal Stability of Cellulose in Ionic Liquids and N-Methylmorpholine-N-oxide