| 1. |
- Brandt, Agnieszka, et al.
(författare)
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Deconstruction of lignocellulosic biomass with ionic liquids
- 2013
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Ingår i: Green Chemistry. - : RSC Publishing. - 1463-9262 .- 1463-9270. ; 15:3, s. 550-583
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Forskningsöversikt (refereegranskat)abstract
- This paper reviews the application of ionic liquids to the deconstruction and fractionation of lignocellulosic biomass, in a process step that is commonly called pretreatment. It is divided into four parts: the first gives background information on lignocellulosic biomass and ionic liquids; the second focuses on the solubility of lignocellulosic biomass (and the individual biopolymers within it) in ionic liquids; the third emphasises the deconstruction effects brought about by the use of ionic liquids as a solvent; the fourth part deals with practical considerations regarding the design of ionic liquid based deconstruction processes.
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| 2. |
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| 3. |
- Gräsvik, John, et al.
(författare)
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Challenges and perspectives of ionic liquids vs. traditional solvents for cellulose processing
- 2012
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Ingår i: Handbook of ionic liquids. - New York : Nova Science Publishers, Inc.. - 9781621003496 - 1621003493 ; , s. 1-34
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Bokkapitel (refereegranskat)abstract
- It is commonly accepted that world-wide production of oil, coal and natural gas will eventually come to a halt, although we still heavily depend on these non-renewable feed stocks and their associated chemical derivatives. Therefore, new, sustainable resources for the production of industrially important chemicals are required. Biomaterials offer much promise in this regard, since they generally contain a lot of cellulose which can be transformed and potentially provide a great source of industrially important chemicals. Presently, only a small part of the annual biomass growth in the world is utilized by industry, while the rest is decaying along natural pathways. In order to effectively process cellulose, it needs to be dissolved in some liquid medium. Present state-of-the-art commercial technologies employ very toxic and hazardous processing with volatile organic solvents like CS2. However, this need not be the case. Ionic liquids (ILs) have shown great potential for the dissolution of cellulose. Some ILs also have attractive physical properties such as: low vapor pressure, high thermal stability and reusability. Thus, they are potentially viable and more environmentally friendly alternatives. Hereby, we present and discuss some of the challenges and perspectives for ILs in terms of their potential for cellulose processing. We briefly review the historical processes and current methods for cellulose processing, and look at alternative processes taking advantage of ILs.
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| 4. |
- Gräsvik, John, et al.
(författare)
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Evaluation of four ionic liquids for pretreatment of lignocellulosic biomass.
- 2014
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Ingår i: BMC Biotechnology. - : Springer. - 1472-6750. ; 14:1, s. 34-45
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Lignocellulosic biomass is highly recalcitrant and various pretreatment techniques are needed to facilitate its effective enzymatic hydrolysis to produce sugars for further conversion to bio-based chemicals. Ionic liquids (ILs) are of interest in pretreatment because of their potential to dissolve lignocellulosic materials including crystalline cellulose.RESULTS: Four imidazolium-based ionic liquids (ILs) ([C=C2C1im][MeCO2], [C4C1im][MeCO2], [C4C1im][Cl], and [C4C1im][HSO4]) well known for their capability to dissolve lignocellulosic species were synthesized and then used for pretreatment of substrates prior to enzymatic hydrolysis. In order to achieve a broad evaluation, seven cellulosic, hemicellulosic and lignocellulosic substrates, crystalline as well as amorphous, were selected. The lignocellulosic substrates included hybrid aspen and Norway spruce. The monosaccharides in the enzymatic hydrolysate were determined using high-performance anion-exchange chromatography. The best results, as judged by the saccharification efficiency, were achieved with [C4C1im][Cl] for cellulosic substrates and with the acetate-based ILs for hybrid aspen and Norway spruce. After pretreatment with acetate-based ILs, the conversion to glucose of glucan in recalcitrant softwood lignocellulose reached similar levels as obtained with pure crystalline and amorphous cellulosic substrates. IL pretreatment of lignocellulose resulted in sugar yields comparable with that obtained with acidic pretreatment. Heterogeneous dissolution with [C4C1im][HSO4] gave promising results with aspen, the less recalcitrant of the two types of lignocellulose included in the investigation.CONCLUSIONS: The ability of ILs to dissolve lignocellulosic biomass under gentle conditions and with little or no by-product formation contributes to making them highly interesting alternatives for pretreatment in processes where high product yields are of critical importance.
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| 5. |
- Gräsvik, John, et al.
(författare)
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Halogen-free ionic liquids and their utilization as cellulose solvents
- 2012
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Ingår i: Journal of Molecular Structure. - : Elsevier. - 0022-2860 .- 1872-8014. ; 1028, s. 156-163
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Tidskriftsartikel (refereegranskat)abstract
- This work demonstrates a novel synthesis route to halogen-free ionic liquids. A one-pot synthetic reaction route avoiding the use of toxic and high-energetic alkyl halides was developed to reduce the environmental impact of the synthesis process of ionic liquids. However, the elimination of halogens and alkyl halides in the preparation of ionic liquids is not just an environmental issue: the aforementioned species are also among the most common and persistent contaminants in today’s Ionic Liquids (ILs). Thus, this paper introduces a range of quaternized nitrogen based ionic liquids, including both aromatic and non-aromatic components, all prepared without alkyl halides in any step of the process. Moreover, bio-renewable precursors such as (bio-)alcohols and carboxylic acids were employed as anion sources and alkylation media, thus avoiding halogen contamination or halogen-containing anions. The IL’s prepared were designed to dissolve cellulose, some of which was included in a cellulose dissolution study using a sulphite cellulose from the company Domsjö.
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| 6. |
- Gräsvik, John, et al.
(författare)
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Ionic liquids for spectroscopy, Coil-3
- 2009
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Ingår i: 3rd Congress on Ionic Liquids May 31 - June 4 2009, Cairns Australia.
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Konferensbidrag (refereegranskat)
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| 7. |
- Gräsvik, John, 1977-
(författare)
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Ionic liquids in bio-refining : synthesis and applications
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fossil fuel resources are not limitless so alternative renewable recourses are needed to fill the void that inevitably will be created once the supplies of this resource start do dwindle. Biomass has the potential to fill this void. Today only a small part of the world annual production of biomass is utilized by humankind, while the rest is allowed to decay naturally. To utilize this renewable resource in the production of fuel and chemicals, the so called bio-refineries specialized in fractionation and making use of all component of the biomass are needed. Ionic liquids could aid in this task.Ionic liquids (ILs) have shown great potential in the field of biomass processing in general and in the pretreatment of (ligno)-cellulose in particular. However, a few things need to be addressed before any large-scale processing can be considered: Finding new routes for IL synthesis that make "on-site" production possible; Investigation into the challenges facing IL pretreatment of (ligno)-cellulose such as possible depolymerization of cellulosic material during the pretreatment and investigating what influence different ILs have on the pretreatment of cellulosic material by methods like enzymatic hydrolysis.This work aims to address these issues and will present a route for IL synthesis making use of alcohols and carboxylic acids both commonly found in a biorefinery. Some of these ILs have also been tested for their ability of dissolve cellulose. Furthermore, this work will address the possibilities but also challenges upon IL-mediated (ligno)-cellulose processing. This includes investigating several ILs and their efficiency as a pretreatment solvent for enzymatic hydrolysis; these studies involve a large variety of different cellulosic materials. This work demonstrated that depolymerization during the IL pretreatment is a possibility and that this can complicate the recovery processes. Furthermore, this work gives guidance into what type of ILs might be suited as pretreatment solvents for different cellulosic materials, including amorphous and crystalline cellulose, processed and native lignocellulose, different types of wood samples and hemicellulose.
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| 8. |
- Hyvärinen, Sari, et al.
(författare)
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Ionic liquid fractionation of woody biomass for fermentable monosaccharides
- 2011
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Ingår i: Cellulose Chemistry and Technology. - : Cellulose Chemistry and Technology. - 0576-9787. ; 45:7-8, s. 483-486
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Tidskriftsartikel (refereegranskat)abstract
- The goal of the present study, devoted to wood fractionation, was to obtain monosaccharides, hexoses and pentoses by means of an ionic liquid (IL) based pre-treatment procedure. Softwood sawdust (maximum particle size of 2 mm) of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) were exposed to ionic liquids – 1-ethyl-3-methylimidazolium acetate (C2mimAce) and 1-ethyl-3-methylimidazolium chloride (C2mimCl) – and thermal treatment (80-150 °C), for various time intervals (0-72 h). Furthermore, cellulose of various origins (plants, wood pulps) was dissolved in C2mimAce and 1-butyl-3-methylimidazolium chloride (C4 mimCl) for the study of the dissolved fractions, stress being laid on monosaccharides and possible by-products, 5-hydroxymethylfurfural and furfural. Knowing the challenges in analysis techniques when ILs and sugars are involved, the present work focuses on the development of suitable analysis methods. To this end, a Hewlett Packard 1100 series HPLC equipped with a refractive index (RI), detector model HP1047 A and a diode array UV detector (DAD) fitted with a carbohydrate column HPX-87K was utilized. Challenges and improvements are discussed.
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| 9. |
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| 10. |
- Normark, Monica, et al.
(författare)
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Biochemical Conversion of Torrefied Norway Spruce After Pretreatment with Acid or Ionic Liquid
- 2016
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Ingår i: Bioenergy Research. - : Springer Science and Business Media LLC. - 1939-1234 .- 1939-1242. ; 9:1, s. 355-368
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Tidskriftsartikel (refereegranskat)abstract
- The chemical effects of torrefaction and the possibility to combine torrefaction with biochemical conversion were explored in experiments with five preparations of wood of Norway spruce that had been torrefied using different degrees of severity. Compositional analysis and analyses using solid-state CP/MAS C-13 NMR, Fourier-transform infrared (FTIR) spectroscopy, and Py-GC/MS showed small gradual changes, such as decreased hemicellulosic content and increased Klason lignin value, for torrefaction conditions in the range from 260 A degrees C and 8 min up to 310 A degrees C and 8 min. The most severe torrefaction conditions (310 A degrees C, 25 min) resulted in substantial loss of glucan and further increase of the Klason lignin value, which was attributed to conversion of carbohydrate to pseudo-lignin. Even mild torrefaction conditions led to decreased susceptibility to enzymatic hydrolysis of cellulose, a state which was not changed by pretreatment with sulfuric acid. Pretreatment with the ionic liquid (IL) 1-butyl-3-methylimidazolium acetate overcame the additional recalcitrance caused by torrefaction, and the glucose yields after 72 h of enzymatic hydrolysis of wood torrefied at 260 A degrees C for 8 min and at 285 A degrees C for 16.5 min were as high as that of IL-pretreated non-torrefied spruce wood. Compared to IL-pretreated non-torrefied reference wood, the glucose production rates after 2 h of enzymatic hydrolysis of IL-pretreated wood torrefied at 260 A degrees C for 8 min and at 285 A degrees C for 16.5 min were 63 and 40 % higher, respectively. The findings offer increased understanding of the effects of torrefaction and indicate that mild torrefaction is compatible with biochemical conversion after pretreatment with alternative solvents that disrupt pseudo-lignin-containing lignocellulose.
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