| 1. |
- Eta, Valerie, et al.
(författare)
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The Effect of Alkoxide Ionic Liquids on the Synthesis of Dimethyl Carbonate from CO2 and Methanol over ZrO2-MgO
- 2011
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Ingår i: Catalysis Letters. - : Springer Science and Business Media LLC. - 1011-372X .- 1572-879X. ; 141:9, s. 1254-1261
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Tidskriftsartikel (refereegranskat)abstract
- The use of carbon dioxide in the synthesis of chemicals, such as dimethyl carbonate (DMC), constitutes an environmentally attractive alternative to hazardous and toxic reagents. However, the direct synthesis of DMC from methanol and CO2 is characterized by low yields due to the reaction equilibrium and the thermodynamic limitations (Delta G(298K)(0) = + 26.3 kj/mol). Alkoxide ionic liquids possessing alkylimidazolium and benzalkonium cations were prepared, characterised and tested together with ZrO2-MgO catalyst for the synthesis of DMC from methanol and CO2. By using the novel ionic liquid as additives, ca. 12% conversion of methanol, and 90% selectivity to DMC was obtained at 120 A degrees C and 7.5 MPa. The water abstracting potential of the ionic liquids influenced the conversion of methanol and the selectivity to DMC. The alkoxide ionic liquids were recovered and reused in DMC synthesis without loss in activity and selectivity.
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| 2. |
- Konwar, Lakhya Jyoti, et al.
(författare)
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Biodiesel production from acid oils using sulfonated carbon catalyst derived from oil-cake waste
- 2014
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Ingår i: Journal of Molecular Catalysis A. - : Elsevier. - 1381-1169 .- 1873-314X. ; 388, s. 167-176
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Tidskriftsartikel (refereegranskat)abstract
- The utilization of oil-cake waste (OCW) derived catalysts in biodiesel production was demonstrated. The sulfonated carbon materials were utilized as catalysts for pretreatment of acid oils (oils containing 8.17-43.73 wt% of free fatty acids). The catalysts could be used to convert free fatty acids (FFA) present in acid oils into corresponding methyl esters within 6-8 h at 80 °C, thus reducing the FFA content to desirable levels below 2 wt%. The esterification activity was found to be dependent on the initial FFA concentration found in the acid oil as well as methanol-to-oil molar ratio. High methanol-to-oil molar ratios and the presence of higher initial FFA concentrations resulted in enhanced esterification rates. Acid oil containing 43.7 wt% FFA was easily converted into mixtures containing up to 71% methyl esters (FAME). The reported catalyst was successfully recycled in five consecutive experiments and exhibited high thermal stability. Most importantly, the catalytic activity of the solid acid was found to outperform homogeneous case when equivalent amount of H2SO4 under similar conditions was applied. Therefore, the OCW derived sulfonated carbon catalyst reported herein could be used as a potential substitute for corrosive, concentrated H2SO4 currently employed for acid oil pretreatment.
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| 3. |
- Mäki-Arvela, Päivi, et al.
(författare)
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The challenge of efficient synthesis of biofuels from lignocellulose for future renewable transportation fuels
- 2012
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Ingår i: International Journal of Chemical Engineering. - : Hindawi Publishing Corporation. - 1687-806X .- 1687-8078. ; , s. 674761-
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Forskningsöversikt (refereegranskat)abstract
- Dehydration of sugars to 5-hydroxymethylfurfural (HMF) has recently been under intensive study by a multitude of research groups. On the other hand, when lignocellulosic biomass is applied as the starting material, very few studies can be found in the open literature. The direct synthesis of HMF, in line with the idea of “one-pot” synthesis strategy from lignocellulose, is demanding since the overall process should encompass dissolution, hydrolysis, and dehydration steps in a single processing unit. Ionic liquid-assisted methods to produce hydroxymethyl-furfural directly from lignocellulosic biomass are reported here together with a short overview of the most important biofuels. In reality, HMF is not suitable to be used as a single-component fuel as such, and, consequently, methods to produce HMF derivatives suitable as liquid fuels are reported.
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| 4. |
- Salminen, Eero, et al.
(författare)
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Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal
- 2014
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Ingår i: Frontiers in Chemistry. - : Frontiers Media SA. - 2296-2646. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat) benzalkonium [ADBA] (alkyldimethylbenzylammonium) was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs). Typically, a SILCA contains metal nanoparticles, enzymes, or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC). The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70% molar yield toward citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide.
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| 5. |
- Salminen, Eero, et al.
(författare)
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Alkaline modifiers as performance boosters in citral hydrogenation over supported ionic liquid catalysts (SILCAs)
- 2012
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Ingår i: Catalysis Today. - : Elsevier. - 0920-5861 .- 1873-4308. ; 196:1, s. 126-131
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Tidskriftsartikel (refereegranskat)abstract
- Supported ionic liquid catalysts (SILCAs) consist of nano-scale catalytic species immobilized in an ionic liquid layer which, in turn, is immobilized on a solid support. In this work, novel SILCAs containing various inorganic alkaline modifiers (e.g. potassium hydroxide) were prepared and applied in citral hydrogenation reactions. The supported ionic liquid catalyst systems demonstrated enhanced reaction rates and improved selectivities toward citronellal in citral hydrogenation. With the addition of an alkaline modifier into ionic liquid layer, the catalyst selectivity increased from 16% to 74%. In fact, a highly selective reaction route toward citronellal was accomplished.
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| 6. |
- Salminen, Eero, et al.
(författare)
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Etherification of 5-Hydroxymethylfurfural to a Biodiesel Component Over Ionic Liquid Modified Zeolites
- 2013
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Ingår i: Topics in catalysis. - : Springer. - 1022-5528 .- 1572-9028. ; 56:9-10, s. 765-769
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Tidskriftsartikel (refereegranskat)abstract
- In this work, ionic liquid (IL) modified H-Beta zeolites were prepared and the physicochemical properties of the catalysts were investigated. IL modified zeolites were applied in 5-hydroxymethylfurfural (HMF) etherification to tert-butoxymethylfurfural (tBMF) which is a potential (bio)diesel component. The best catalyst, IL-H-Beta-25, yielded at BMF selectivity of 76 % corresponding to a HMF conversion of 46 %.
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| 7. |
- Salminen, Eero, et al.
(författare)
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Isomerisation of a-Pinene Oxide to Campholenic Aldehyde OverSupported Ionic Liquid Catalysts (SILCAs)
- 2014
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Ingår i: Topics in catalysis. - : Springer Science+Business Media B.V.. - 1022-5528 .- 1572-9028. ; 57:17-20, s. 1533-1538
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Tidskriftsartikel (refereegranskat)abstract
- The isomerisation of α-pinene oxide to campholenic aldehyde, an expensive ingredient utilized by e.g. flavor industry, was studied over Supported Ionic Liquid Catalysts (SILCAs) consisting of catalytically active species residing in ionic liquid. The ionic liquid, in turn, was immobilized on a solid support material. SILCAs were demonstrated as efficient catalysts for the transformation of α-pinene oxide into campholenic aldehyde, with the product distribution and activity being dependent on the nature of the ionic liquid.
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| 8. |
- Salminen, Eero, et al.
(författare)
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Kinetics upon Isomerization of α,β-Pinene Oxides over Supported Ionic Liquid Catalysts Containing Lewis Acids
- 2014
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Ingår i: Journal of Industrial and Engineering Chemistry. - : American Chemical Society (ACS). - 1226-086X .- 1876-794X .- 0888-5885 .- 1520-5045. ; 53:52, s. 20107-20115
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Tidskriftsartikel (refereegranskat)abstract
- Wood extractives such as α-pinene oxide and β-pinene oxide are important renewable chemicals for the synthesis of fine chemicals, pharmaceuticals, and value-added intermediates. In this work, catalytic transformations of biomass derived extractives, isomerization of α,β-pinene oxides were studied over supported ionic liquid catalysts (SILCAs). SILCAs consist of catalytic species (e.g., metal nanoparticles or metal complexes) in a thin layer of ionic liquid which is immobilized on a solid support material (e.g., active carbon cloth). The reaction kinetics of the isomerization reactions over supported ionic liquid catalysts were studied and modeled. Mechanistic kinetic models describing the differences in selectivity and activity of the catalysts containing different ionic liquids were developed, and the models described the reaction rates and product distributions very well.
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| 9. |
- Virtanen, Pasi, et al.
(författare)
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Selective hydrogenation for fine chemical synthesis
- 2014
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Ingår i: Supported ionic liquids. - Weinheim, Germany : Wiley-VCH Verlagsgesellschaft. - 9783527324293 - 9783527654819 - 9783527654802 - 9783527654796 - 9783527654789 ; , s. 251-262
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Bokkapitel (refereegranskat)abstract
- Hydrogenation is an important and widely applied reaction in chemical industry. Supported ionic liquid (IL) type catalysts have shown good performance in various hydrogenation reactions. This chapter introduces a few case studies where supported IL catalysis has been applied in hydrogenation reactions. The case studies highlight the novelty of supported IL catalyst (SILCA) catalysts. Selective hydrogenation of α,ß-unsaturated aldehydes, ketones, and esters, in general, is a versatile pathway to obtain many interesting products that can be used in perfumes, hardening of fats, preparation of pharmaceuticals, and synthesis of organic intermediates. SILCAs have been successfully demonstrated to act as catalysts in chemoselective hydrogenations, and thus an analogous concept has been applied for the synthesis of chiral metal complexes in ILs supported on heterogeneous catalysts.
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