Pre-treatment of lignocellulosic biomass using ionic liquids: wheat straw fractionation.
TL;DR: The method developed and described here allows the separation into high purity carbohydrate and lignin fractions and permits an efficient IL recovery and a versatility of the established method was confirmed by the IL reuse.
About: This article is published in Bioresource Technology.The article was published on 2013-08-01 and is currently open access. It has received 254 citations till now. The article focuses on the topics: Cellulose & Fractionation.
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TL;DR: This review focuses on the catalytic chemical conversion of lignocellulose and its primary ingredients into value-added chemicals and fuel products using ILs as the reaction media.
Abstract: Innovative valorization of naturally abundant and renewable lignocellulosic biomass is of great importance in the pursuit of a sustainable future and biobased economy. Ionic liquids (ILs) as an important kind of green solvents and functional fluids have attracted significant attention for the catalytic transformation of lignocellulosic feedstocks into a diverse range of products. Taking advantage of some unique properties of ILs with different functions, the catalytic transformation processes can be carried out more efficiently and potentially with lower environmental impacts. Also, a new product portfolio may be derived from catalytic systems with ILs as media. This review focuses on the catalytic chemical conversion of lignocellulose and its primary ingredients (i.e., cellulose, hemicellulose, and lignin) into value-added chemicals and fuel products using ILs as the reaction media. An outlook is provided at the end of this review to highlight the challenges and opportunities associated with this interes...
627 citations
TL;DR: In this article, the most promising current routes towards fractionation and/or depolymerization of lignin are reviewed, and challenges for integrated biorefineries and for launching new Lignin-based compounds and products are discussed.
496 citations
TL;DR: In this article, the applicability of ionic liquids and deep eutectic mixtures in a variety of extraction techniques, including but not limited to liquid-and solid-phase (micro) extraction, microwave-assisted extraction, ultrasound assisted extraction and pressurized liquid extraction, is discussed.
Abstract: In recent years, ionic liquids and deep eutectic mixtures have demonstrated great potential in extraction processes relevant to several scientific and technological activities. This review focuses on the applicability of these sustainable solvents in a variety of extraction techniques, including but not limited to liquid- and solid-phase (micro) extraction, microwave-assisted extraction, ultrasound-assisted extraction and pressurized liquid extraction. Selected applications of ionic liquids and deep eutectic mixtures on analytical method development, removal of environmental pollutants, selective isolation, and recovery of target compounds, purification of fuels, and azeotrope breaking are described and discussed.
327 citations
TL;DR: An overview of the most important pretreatment methods available, including those that are based on the use of green solvents (supercritical fluids and ionic liquids) and those that have a lower impact on the environment.
Abstract: Lignocellulosic materials, such as forest, agriculture, and agroindustrial residues, are among the most important resources for biorefineries to provide fuels, chemicals, and materials in such a way to substitute for, at least in part, the role of petrochemistry in modern society. Most of these sustainable biorefinery products can be produced from plant polysaccharides (glucans, hemicelluloses, starch, and pectic materials) and lignin. In this scenario, cellulosic ethanol has been considered for decades as one of the most promising alternatives to mitigate fossil fuel dependence and carbon dioxide accumulation in the atmosphere. However, a pretreatment method is required to overcome the physical and chemical barriers that exist in the lignin-carbohydrate composite and to render most, if not all, of the plant cell wall components easily available for conversion into valuable products, including the fuel ethanol. Hence, pretreatment is a key step for an economically viable biorefinery. Successful pretreatment method must lead to partial or total separation of the lignocellulosic components, increasing the accessibility of holocellulose to enzymatic hydrolysis with the least inhibitory compounds being released for subsequent steps of enzymatic hydrolysis and fermentation. Each pretreatment technology has a different specificity against both carbohydrates and lignin and may or may not be efficient for different types of biomasses. Furthermore, it is also desirable to develop pretreatment methods with chemicals that are greener and effluent streams that have a lower impact on the environment. This paper provides an overview of the most important pretreatment methods available, including those that are based on the use of green solvents (supercritical fluids and ionic liquids).
307 citations
TL;DR: This paper deals with recent trends in the bioethanol production as a fuel from different renewable raw materials as well as with its separation and purification processes.
Abstract: Production of biofuels from renewable feedstocks has captured considerable scientific attention since they could be used to supply energy and alternative fuels. Bioethanol is one of the most interesting biofuels due to its positive impact on the environment. Currently, it is mostly produced from sugar- and starch-containing raw materials. However, various available types of lignocellulosic biomass such as agricultural and forestry residues, and herbaceous energy crops could serve as feedstocks for the production of bioethanol, energy, heat and value-added chemicals. Lignocellulose is a complex mixture of carbohydrates that needs an efficient pretreatment to make accessible pathways to enzymes for the production of fermentable sugars, which after hydrolysis are fermented into ethanol. Despite technical and economic difficulties, renewable lignocellulosic raw materials represent low-cost feedstocks that do not compete with the food and feed chain, thereby stimulating the sustainability. Different bioprocess operational modes were developed for bioethanol production from renewable raw materials. Furthermore, alternative bioethanol separation and purification processes have also been intensively developed. This paper deals with recent trends in the bioethanol production as a fuel from different renewable raw materials as well as with its separation and purification processes.
284 citations
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...Pretreatment of wheat straw by using IL ([emim][CH3COO]) resulted in high purity cellulose and hemicellulose fractions as well as 87 % pure lignin (73)....
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References
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TL;DR: In this paper, the authors demonstrate that cellulose can be dissolved without activation or pretreatment in, and regenerated from, 1-butyl-3-methylimidazolium chloride and other hydrophilic ionic liquids.
Abstract: We report here initial results that demonstrate that cellulose can be dissolved without activation or pretreatment in, and regenerated from, 1-butyl-3-methylimidazolium chloride and other hydrophilic ionic liquids. This may enable the application of ionic liquids as alternatives to environmentally undesirable solvents currently used for dissolution of this important bioresource.
4,276 citations
TL;DR: In this article, the dissolution of cellulose with ionic liquids and its application were reviewed, where cellulose can be easily regenerated from its ionic liquid solutions by addition of water, ethanol or acetone.
1,488 citations
TL;DR: The various hemicelluloses structures present in lignocellulose, the range of pre-treatment and hydrolysis options including the enzymatic ones, and the role of different microbial strains on process integration aiming to reach a meaningful consolidated bioprocessing are reviewed.
1,355 citations
TL;DR: In this article, a comprehensive database on physical properties of ionic liquids (ILs), collected from 109 kinds of literature sources in the period from 1984 through 2004, has been presented, which includes 1680 pieces of data on the physical properties for 588 available ILs, from which 276 kinds of cations and 55 kinds of anions were extracted.
Abstract: A comprehensive database on physical properties of ionic liquids (ILs), which was collected from 109 kinds of literature sources in the period from 1984 through 2004, has been presented. There are 1680 pieces of data on the physical properties for 588 available ILs, from which 276 kinds of cations and 55 kinds of anions were extracted. In terms of the collected database, the structure-property relationship was evaluated. The correlation of melting points of two most common systems, disubstituted imidazolium tetrafluoroborate and disubstituted imidazolium hexafluorophosphate, was carried out using a quantitative structure-property relationship method.
1,102 citations
TL;DR: Ionic liquid pretreatment enabled a significant enhancement in the rate of enzyme hydrolysis of the cellulose component of switchgrass, with a rate increase of 16.7-fold, and a glucan yield of 96.0% obtained in 24h.
995 citations