| 1. |
- Anugwom, Ikenna, et al.
(författare)
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Esterified Lignin from Construction and Demolition Waste (CDW) as a Versatile Additive for Polylactic-Acid (PLA) Composites-The Effect of Artificial Weathering on its Performance
- 2022
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Ingår i: Global Challenges. - : Wiley-VCH Verlagsgesellschaft. - 2056-6646. ; 6:8
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Tidskriftsartikel (refereegranskat)abstract
- Demand for sustainable packaging and building materials has increased the need for biobased additives. Biocomposites can often be exposed to different weather conditions and UV irradiation. Thus, additives to prevent the negative impact of weathering are generally added to composites. This study aims to evaluate using esterified lignin as an additive against weathering effects in polylactic-acid (PLA) composites. Lignin is extracted from construction and demolition waste (CDW) wood using a deep eutectic solvent then esterified and tested as an additive in the fabrication of biobased composites. For comparison, lignin from birch is used as a raw material for an additive. Esterification is confirmed by solid-state N MR analysis. Samples are exposed to artificial weathering for 700 hours and their impact strength and color change properties are measured. The results indicate that esterified lignin from CDW (CDW e-lignin) as an additive protects the biocomposite from the weathering impact. The sample containing the CDW e-lignin as an additive suffers only a 4.3% of reduction of impact strength, while the samples that contain commercial additives lose clearly more of their impact strength (from 23.1% to 61.1%). Based on the results CDW e-lignin is a good additive to prevent weathering. As a conclusion, the esterified lignin from CDW, is a versatile additive for composite production.
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| 2. |
- Anugwom, Ikenna, et al.
(författare)
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In quest for the optimal delignification of lignocellulosic biomass using hydrated, SO2 switched DBU MEASIL switchable ionic liquid
- 2016
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 297, s. 256-264
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, various process parameters aiming at optimal short-time-high-temperature (STHT) process were studied upon fractionation of Nordic woody biomass into its primary constituents. Highly diluted, aqueous 'SO2-switched' switchable ionic liquid (SIL) based on an alkanol amine (monoethanol amine, MEA) and an organic superbase (1,8-diazabicyclo-[5.4.0]-undec-7-ene, DBU) was applied. The ultimate goal was to develop a more sustainable, environmentally friendly and cost efficient systems for efficient separation of the lignocellulosic fractions. One of the main products from the SIL fractionation is cellulose-rich pulp with very low lignin content, complemented with hemicelluloses. The NMR results reveal that substantial removal of lignin occurs even when relatively low amount of SIL was used. Further, a simple mathematical model describing the dissolution of the lignocellulose components (hemicellulose and lignin) and weight loss of wood as a function of time is described. Moreover, the most efficient process involved the use of SpinChem (R) rotating bed reactor while upon use of a flow through (loop) reactor, promising results were obtained at a treatment time of 4 h. Still, all the reactor systems studied gave rise to a rather low removal of hemicelluloses which mean that the solvent system is primary selective towards lignin dissolution.
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| 3. |
- Anugwom, Ikenna, et al.
(författare)
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Switchable ionic liquids as delignification solvents for lignocellulosic materials
- 2014
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Ingår i: ChemSusChem. - : John Wiley & Sons. - 1864-5631 .- 1864-564X. ; 7:4, s. 1170-1176
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Tidskriftsartikel (refereegranskat)abstract
- The transformation of lignocellulosic materials into potentially valuable resources is compromised by their complicated structure. Consequently, new economical and feasible conversion/fractionation techniques that render value-added products are intensely investigated. Herein an unorthodox and feasible fractionation method of birch chips (B. pendula) using a switchable ionic liquid (SIL) derived from an alkanol amine (monoethanol amine, MEA) and an organic super base (1,8-diazabicyclo-[5.4.0]-undec-7-ene, DBU) with two different trigger acid gases (CO2 and SO2 ) is studied. After SIL treatment, the dissolved fractions were selectively separated by a step-wise method using an antisolvent to induce precipitation. The SIL was recycled after concentration and evaporation of anti-solvent. The composition of undissolved wood after MEA-SO2 -SIL treatment resulted in 80 wt % cellulose, 10 wt % hemicelluloses, and 3 wt % lignin, whereas MEA-CO2 -SIL treatment resulted in 66 wt % cellulose, 12 wt % hemicelluloses and 11 wt % lignin. Thus, the MEA-SO2 -SIL proved more efficient than the MEA-CO2 -SIL, and a better solvent for lignin removal. All fractions were analyzed by gas chromatography (GC), Fourier transform infrared spectroscopy (FT-IR), (13) C nuclear magnetic resonance spectroscopy (NMR) and Gel permeation chromatography (GPC).
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| 4. |
- Anugwom, Ikenna, et al.
(författare)
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Switchable ionic liquids (SILs) based on glycerol and acid gases
- 2011
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Ingår i: RSC Advances. - : The Royal Society of Chemistry. - 2046-2069. ; 1:3, s. 452-457
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Tidskriftsartikel (refereegranskat)abstract
- New types of switchable ionic liquids (SILs), containing 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU), glycerol and an acid gas (CO2, SO2), were synthesized and characterized in this study. [DBU][Carbonate] or [sulfonate] were easily synthesized from a non-ionic mixture of molecular organic polyol and amidine base upon bubbling of an acid gas (CO2, SO2). Moreover, they were switched back to the original molecular solvents by flushing out the acid gas (CO2, SO2) by heating and/or bubbling an inert gas such as N2 through it. The structures of the SILs were confirmed by NMR and FTIR. The change from low polarity (molecular solvent) to high polarity (Switchable Ionic Liquid, SIL) was also indicated by the changes in properties, such as viscosity and miscibility with different organic solvents. The decomposition temperatures of the SILs were determined by means of Thermo Gravimetric Analysis (TGA) and gave values in the range of 50 °C and 120 °C for DBU-glycerol-CO2 (SIL1) and DBU-glycerol-SO2 (SIL2), respectively. Due to the reasonable decomposition temperatures, these novel SILs can be employed in multiple applications.
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| 5. |
- Anugwom, Ikenna, et al.
(författare)
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The effect of switchable ionic liquid (SIL) treatment on the composition and crystallinity of birch chips (Betula pendula) using a novel alkanol amine-organic superbase-derived SIL
- 2014
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Ingår i: Green Processing and Synthesis. - : Walter de Gruyter GmbH. - 2191-9542 .- 2191-9550. ; 3:2, s. 147-154
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Tidskriftsartikel (refereegranskat)abstract
- Two-step treatment of birch chips (Betula pendula) was tested using diethanolamine (DEA)-1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU)-CO2-switchable ionic liquid (SIL), resulting in a 23% weight reduction in 24 h. The weight of the chips was reduced to 32% of their initial weight upon the second treatment with fresh SIL. SIL to wood ratio of 5:1, at 100°C for 24 h, without stirring, was applied in both steps. The relative amount of wood lignin reduced from 24% to 14% after two treatment cycles. The relative amount of cellulose of the undissolved fraction after SIL treatment increased from 43% (native birch wood) to 68% after the second cycle. Also, the undissolved material was efficiently fibrillated. The dissolved materials recovered from spent SIL, after treatment, contained high xylan content, about 90% of the total hemicelluloses, which was 85% of the recovered material. The powder X-ray diffraction (XRD) results revealed that the crystallinity of the undissolved material increased slightly, indicating dissolution of the amorphous material. Moreover, transformation of cellulose form I to form II in the remaining undissolved chips was not observed.
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| 6. |
- Anugwom, Ikenna, et al.
(författare)
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Towards optimal selective fractionation for Nordic woody biomass using novel amine–organic superbase derived switchable ionic liquids (SILs)
- 2014
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Ingår i: Biomass and Bioenergy. - : Elsevier. - 0961-9534 .- 1873-2909. ; 70, s. 373-381
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Improved fractionation process conditions for wood dissolution with switchable ionic liquids (SILs) were determined. The short time, high temperature (STHT) system was introduced as a selective and efficient way to extract components from lignocellulosic material. A SIL based on monoethanol amine (MEA) and 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) formed via coupling with SO2, was applied as a solvent in a 1:3 weight ratio with water. In essence, selective dissolution of mainly lignin was achieved by means of the aqueous SIL at 160 °C (∼6.1 bar corresponding to the vapor pressure of water) in 2 h and in a pressure vessel, for both hard- and soft-wood. About 95 wt-% of wood lignin was extracted. The dissolved components in the spent SIL were recovered by the addition of an anti-solvent whereupon over 70% of the dissolved components were recovered; the recovered fraction contained 19 wt-% hemicellulose while the rest of the material was in essence lignin. The non-dissolved, fluffy material contained ∼70 wt-% cellulose and ∼20 wt-% hemicellulose – a consistency resembling that of Kraft pulp.
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| 7. |
- Anugwom, Ikenna, et al.
(författare)
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Treating birch wood with a switchable 1,8-diazabicyclo-[5.4.0]-undec-7-ene-glycerol carbonate ionic liquid
- 2012
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Ingår i: Holzforschung. - : Walter de Gruyter GmbH. - 0018-3830 .- 1437-434X. ; 66:7, s. 809-815
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Tidskriftsartikel (refereegranskat)abstract
- The suitability of a new switchable ionic liquid (SIL) has been investigated as a solvent for fractionation of lignocellulosic materials. SIL was prepared from inexpensive chemicals, e. g., glycerol, CO2, and 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU). Fresh Nordic birch wood (B. pendula) was treated with the SIL for a time period of 1-5 days at 100 degrees C and under atmospheric pressure. Upon SIL treatment, at best, 57 % of the hemicelluloses were dissolved and 50 % of lignins were dissolved from the native birch. The slightly fibrillated SIL treated chips contained about 55 % cellulose. Up to 76 % of the recovered species removed from the spent SIL liquor was originating from hemicelluloses, mainly from xylan. The spent SILs were reused for fresh wood dissolution in four consecutive cycles and each time the wood dissolution efficiency was similar. SILs could offer affordable (easy-to-synthesize) solvent systems for partial elimination of hemicelluloses and lignin from wood. SILs can also be prepared in-situ and on-site.
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| 8. |
- Berglund, Linn, et al.
(författare)
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Switchable ionic liquids enable efficient nanofibrillation of wood pulp
- 2017
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Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 24:8, s. 3265-3279
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Tidskriftsartikel (refereegranskat)abstract
- Use of switchable ionic liquid (SIL) pulp offers an efficient and greener technology to produce nanofibers via ultrafine grinding. In this study, we demonstrate that SIL pulp opens up a mechanically efficient route to the nanofibrillation of wood pulp, thus providing both a low cost and chemically benign route to the production of cellulose nanofibers. The degree of fibrillation during the process was evaluated by viscosity and optical microscopy of SIL treated, bleached SIL treated and a reference pulp. Furthermore, films were prepared from the fibrillated material for characterization and tensile testing. It was observed that substantially improved mechanical properties were attained as a result of the grinding process, thus signifying nanofibrillation. Both SIL treated and bleached SIL treated pulps were fibrillated into nanofibers with fiber diameters below 15 nm thus forming networks of hydrophilic nature with an intact crystalline structure. Notably, it was found that the SIL pulp could be fibrillated more efficiently than traditional pulp since nanofibers could be produced with more than 30% less energy when compared to the reference pulp. Additionally, bleaching reduced the energy demand by further 16%. The study demonstrated that this switchable ionic liquid treatment has considerable potential in the commercial production of nanofibers due to the increased efficiency in fibrillation.
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| 9. |
- Duan, Ran, et al.
(författare)
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Fibre Stress-Strain Response of High-Temperature Chemi-Thermomechanical Pulp Treated with Switchable Ionic Liquids
- 2016
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Ingår i: BioResources. - : BioResources. - 1930-2126. ; 11:4, s. 8570-8588
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Tidskriftsartikel (refereegranskat)abstract
- The removal of lignin from a high-temperature chemi-thermomechanical pulp (HT-CTMP) using a switchable ionic liquid prepared from an organic superbase (1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU)), monoethanol amine (MEA), and SO2 was investigated. The objective was to measure the fibre properties before and after removal of the lignin to analyse the contributions from lignin in the HT-CTMP fibre to the tensile properties. It was found that the fibre displacement at break - measured in zero span, which is related to fibre strain at break - was not influenced by the lignin removal in this ionic liquid system when tested dry. There was a small increase in displacement at break and a reduction in tensile strength at zero span when tested after rewetting. At short span, the displacement at break decreased slightly when lignin was removed, while tensile strength was almost unaffected when tested dry. Under rewetted conditions, the displacement at break increased and tensile strength decreased after lignin removal. Nevertheless, no dramatic differences in the pulp properties could be observed. Under the experimental conditions, treatment with the ionic liquid reduced the lignin content from 37.4 to 15.5 wt%.
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| 10. |
- Eta, Valerie, et al.
(författare)
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Catalysis for carbon dioxide activation
- 2013
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Ingår i: Catalysis in Finland. - Oulu : Finnish Catalysis Society. - 9789529330850 - 9789529330867
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 11. |
- Eta, Valerie, et al.
(författare)
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Enhanced mass transfer upon switchable ionic liquid mediated wood fractionation
- 2014
-
Ingår i: Industrial crops and products (Print). - : Elsevier. - 0926-6690 .- 1872-633X. ; 55, s. 109-115
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Tidskriftsartikel (refereegranskat)abstract
- The fractionation of lignocellulosic biomass to its major components is the primary step towards the conversion of biomass-based biopolymers to commodity chemicals in the integrated biorefinery process. Wood chips encased in a SpinChem® device and attached to the stirrer of a batch autoclave were used together with switchable ionic liquids (SILs) for the selective fractionation of hemicelluloses and lignin. Stirring of the wood chips in the SpinChem® device facilitated the diffusion of SIL into the chips through forced recirculation and at the same time avoiding mechanical fibrillation. The treatment of birch chips (Betula pendula) with SILs comprising 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU), monoethanolamine (MEA) and CO2 at 120 °C in a SpinChem® device resulted in the fractionation of 82 wt.% hemicelluloses and 90 wt.% lignin, leaving the cellulose-rich non-dissolved material partially fibrillated and softened. The dissolved hemicelluloses and lignin were selectively precipitated using isopropanol and recovered from the spent SIL.
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| 12. |
- Eta, Valerie, et al.
(författare)
-
Loop vs. batch reactor setups in the fractionation of birch chips using switchable ionic liquids
- 2014
-
Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 238, s. 242-248
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Tidskriftsartikel (refereegranskat)abstract
- The fractionation of lignocellulosic feedstock into its major components with high purity represents an important commercialization milestone in the transformation of lignocellulosic forest derived products into fuels and commodity chemicals. A comparison between the traditionally used batch reactor and loop reactor systems demonstrates that improved dissolution of hemicelluloses and lignin are obtained using switchable ionic liquids in a loop reactor system which facilitates decreased heat and mass transfer restrictions. The treatment of birch chips using switchable ionic liquid (SIL) based on 1,8-diazabicyclo-[5.4.0]-undec-7-ene, CO2 and diethanolamine at 120 °C for 30 h in a loop reactor resulted in 24% loss of original weight of wood corresponding to dissolution of 52 wt.% of hemicelluloses and 42 wt.% of lignin, respectively, as opposed to 20% weight loss corresponding to 43 wt.% dissolution of hemicelluloses and 38 wt.% of lignin in the batch system. The non-dissolved material obtained from both reactors was efficiently fibrillated and softened cellulose fibres. The flow of switchable ionic liquid through the loop reactor and agitation of the chips enhanced the dissolution of hemicelluloses and lignin. The dissolved fractions recovered from spent SIL after treatment contained both hemicelluloses and lignin.
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| 13. |
- Gavilà, Llorenç, et al.
(författare)
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Lactic acid production from renewable feedstock : fractionation, hydrolysis, and fermentation
- 2018
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Ingår i: Advanced Sustainable Systems. - : Wiley. - 2366-7486. ; 2:3
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, an integrated fractionation with a switchable ionic liquid (SIL), pulp hydrolysis, and lactic acid fermentation is carried out. For this, SO2-swithced SIL is used for fractionation of sugar cane (Saccharum officinarum) bagasse and giant cane (Arundo donax, AD). SIL is able to extract ≈2/3 of lignin when relatively large wood chips (≈4 mm) are used without any mechanical agitation and just 1 h of treatment time for AD. Furthermore, SIL reuse is successfully demonstrated for four runs. Subsequently, the produced pulps are hydrolyzed within 15 min in a microwave reactor, producing a glucose rich hydrolysates. Finally, these hydrolysates are used as a carbohydrate source for Lactobacillus delbrueckii fermentation, which selectively transform all glucose present into optically pure D-lactic acid. Hence, the whole chain for lactic acid production from biomass is successfully demonstrated.
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| 14. |
- Khokarale, Santosh G., et al.
(författare)
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Switchable polarity liquids
- 2018
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Ingår i: Polymerized ionic liquids. - London : Royal Society of Chemistry. - 9781782629603 - 9781788010535 - 9781788012218 ; , s. 143-179
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In this chapter, the synthesis and characterization, as well as applications, of various types of switchable polarity solvents (SPSs) are summarized in order to unravel their composition and switchable nature. The polarity 'switch' between a molecular liquid and ionic species in the case of SPSs is described on the basis of interactions occurring for various types of organic bases or silylamines with acid gases such as CO2 or SO2 and in the absence or presence of alcohols. The chapter consists of two principal parts where the synthesis of SPS systems is described as a result of interaction of one or two molecular components with acid gases. The molecular liquids in two-component SPSs comprise organic superbases such as 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) or 1,1,3,3-tetramethylguanindine (TMG or its derivatives) and lower to higher alcohols or water or glycerol. The one-component system involves the use of silylamines for SPS synthesis. The change in the composition and polarity of the reaction mixture during the synthesis, as well as the switchable nature of these SPSs, is demonstrated by gravimetric, spectroscopic and conductivity measurements. In the second part, various applications of SPS systems are described along with how the special characteristics of SPSs can be utilized.
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| 15. |
- Pezoa-Conte, R., et al.
(författare)
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Deconstruction of the green alga Ulva rigida in ionic liquids : closing the mass balance
- 2015
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Ingår i: Algal Research. - : Elsevier. - 2211-9264. ; 12, s. 262-273
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Tidskriftsartikel (refereegranskat)abstract
- Algae are known to grow at high rates compared to terrestrial plants that contain comparable amounts of carbohydrates by weight. Therefore, this renders them attractive in terms of any biorefinery concept. In this work the green alga Ulva rigida, containing 40 wt.% of carbohydrates was pretreated with a switchable ionic liquid (SIL), distillable ionic liquid (DIL) and low-viscosity ionic liquid (LVIL). The SIL DBU–MEA–SO2 was prepared from a mixture of mono-ethanolamine (MEA) and 1,8-diazabicyclo-[5,4,0]-undec-7-ene (DBU) that was coupled with sulfur dioxide (SO2), whereas the DIL [TMGH+][EtCO2−] (1,1,3,3-tetramethylguanidine propionate) was synthesized by a simple acid–base neutralization reaction. Consequently, the LVIL [HDBU+][5OF−] protonated 1,8-diazabicyclo-[5,4,0]-undec-7-ene- 2,2,3,3,4,4,5,5-octafluoro-1-pentoxide was used as received. The treatments were carried out in the temperature range of 100–160 °C for 6 h. The products obtained after the treatments were analyzed using different techniques like ICP, OES, SEM, TEM, TGA, FTIR and carbohydrate determination by GC. Upon treatment with DIL up to 67 wt.% of carbohydrates could be dissolved. For the first time, processing of U. rigida was carried out in ionic liquids so that the mass balance of the process was obtained. It can be concluded that 1,1,3,3-tetramethylguanidine propionate shows significant potential when aiming at releasing carbohydrates from algal biomass that, consequently, can be applied in the production of platform chemicals and/or biofuels such as bioethanol.
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| 16. |
- Ravanal, María Cristina, et al.
(författare)
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Comparison of different types of pretreatment and enzymatic saccharification of Macrocystis pyrifera for the production of biofuel
- 2016
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Ingår i: Algal Research. - : Elsevier. - 2211-9264. ; 13, s. 141-147
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the brown algae Macrocystis pyrifera were pretreated with dilute sulfuric acid, water and three different types of ionic liquids (ILs): 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]), 1,5-diazabicyclo[4.3.0]non-5-ene acetate ([DBNH][OAc]) and 1,8-diazabicyclo-[5.4.0]–undec-7-ene–sulfurdioxide–monoethanolamine (DBU–MEA–SO2–SIL), to disassemble the complex polysaccharide structure. After each pretreatment procedure, enzymatic saccharification was performed to release the monosaccharides. The main building blocks of M. pyrifera were processed by derivatization via acid methanolysis and subjected to gas chromatographic analysis. It was found that the main constituents were alginate (60.6 wt.%) and cellulose (22.6 wt.%) of total carbohydrate content. The degradation of alginate requires the action of alginate lyase and oligoalginate lyase, which hydrolyze the main chain in a synergistic mechanism releasing uronic acid (unsaturated uronate). Upon saccharification of cellulose, cellulases and β-glucosidase were used allowing the release of glucose. It was found that the best pretreatment strategy for M. pyrifera consisted of a pretreatment with 2 vol.% sulfuric acid, followed by saccharification of cellulose with a mixture of cellulases at pH 5.2 for 4 h at 50 °C or by saccharification of alginate with the enzyme lyase/oligoalginate lyase at pH 7.5 for 2 h at 37 °C. The process resulted in a release of 68.4 wt.% of glucose (55.74 ± 0.05 mg glucose/g algae) whereas in the case of alginate 85.8 wt.% of uronic acid (193.7 ± 10.6 mg uronic acid/g algae) was released. To the best of our knowledge this is the first time that saccharification of both cellulose and alginate from brown algae is reported.
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| 17. |
- Rogne, Per, et al.
(författare)
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Real-time 31P NMR investigation on the catalytic behavior of the enzyme Adenylate kinase in the matrix of a switchable ionic liquid
- 2015
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Ingår i: ChemSusChem. - : John Wiley & Sons. - 1864-5631 .- 1864-564X. ; 8:2, s. 3764-3768
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Tidskriftsartikel (refereegranskat)abstract
- The integration of highly efficient enzymatic catalysis with the solvation properties of ionic liquids for an environmentally friendly and efficient use of raw materials such as wood requires fundamental knowledge about the influence of relevant ionic liquids on enzymes. Switchable ionic liquids (SIL) are promising candidates for implementation of enzymatic treatments of raw materials. One industrially interesting SIL is constituted by monoethanol amine (MEA) and 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) formed with sulfur dioxide (SO2) as the coupling media (DBU-SO2-MEASIL). It has the ability to solubilize the matrix of lignocellulosic biomass while leaving the cellulose backbone intact. Using a novel 31P NMR-based real-time assay we show that this SIL is compatible with enzymatic catalysis because a model enzyme, adenylate kinase, retains its activity in up to at least 25 wt % of DBU-SO2-MEASIL. Thus this SIL appears suitable for, for example, enzymatic degradation of hemicellulose.
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