Browsing by Author "Llorca, Jordi"

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  • A comparative study of water-immiscible organic solvents in the production of furfural from xylose and birch hydrolysate
    (2019-04-25) Gómez Millán, Gerardo; Hellsten, Sanna; King, Alistair W.T.; Pokki, Juha-Pekka; Llorca, Jordi; Sixta, Herbert
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Furfural (FUR) was produced from xylose using a biphasic batch reaction system. Water-immiscible organic solvents such as isophorone, 2-methyltetrahydrofuran (2-MTHF) and cyclopentyl methyl ether (CPME) were used to promptly extract FUR from the aqueous phase in order to avoid the degradation to humins as largely as possible. The effect of time, temperature, organic solvent and organic-to-aqueous ratio on xylose conversion and FUR yield were investigated in auto-catalyzed conditions. Experiments at three temperatures (170, 190 and 210 °C) were carried out in a stirred microwave-assisted batch reactor, which established the optimal conditions for achieving the highest FUR yield. The maximum FUR yields from xylose were 78 mol% when using CPME, 48 mol% using isophorone and 71 mol% in the case of 2-MTHF at an aqueous to organic phase ratio of 1:1 (v/v). Birch hydrolysate was also used to show the high furfural yield that can be obtained in the biphasic system under optimized conditions. The present study suggests that CPME can be used as a green and efficient extraction solvent for the conversion of xylose into furfural without salt addition.
  • Fast furfural formation from xylose using solid acid catalysts assisted by a microwave reactor
    (2018-12-15) Gómez Millán, Gerardo; El Assal, Zouhair; Nieminen, Kaarlo; Hellsten, Sanna; Llorca, Jordi; Sixta, Herbert
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The production of furfural (FUR) from xylose was carried out using sulfated zirconia (SZ) on cordierite, alumina on cordierite and commercially-available polymeric solid catalysts (Amberlyst DT and Nafion NR40) to provide insights into the reaction pathways and kinetics for the dehydration of xylose in aqueous phase. Experiments conducted at three temperatures were investigated (170, 190 and 210 °C) in a stirred microwave-assisted batch reactor, which established the optimal conditions to obtain the highest FUR yield as well as extensive and fast xylose conversion. The maximum FUR yields obtained from xylose were 41 mol% when using SZ on cordierite in 2 min (at 210 °C), 43 mol% when using alumina on cordierite in 30 min (at 210 °C) and 48 mol% for an auto-catalyzed system in 60 min (at 210 °C). Based on the experimental results, a reaction mechanism was proposed considering the formation of an intermediate from xylose when solid acid catalysts were added. After five reusability cycles using SZ on cordierite, this catalyst can be regenerated with a similar performance and similar FUR yield on the 6th cycle.
  • Furfural production from xylose and birch hydrolysate liquor in a biphasic system and techno-economic analysis
    (2021) Gómez Millán, Gerardo; Bangalore Ashok, Rahul Prasad; Oinas, Pekka; Llorca, Jordi; Sixta, Herbert
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Furfural has been highlighted as one of the top ten most rewarding bio-based building blocks by the US Department of Energy. In this study, furfural was produced from xylose and birch hydrolysate liquor employing a batch reactor in a biphasic system. The formation of furfural was conducted under auto-catalyzed conditions. 2-sec-Butylphenol was used as extractant to promptly extract furfural from the aqueous phase in order to minimize furfural degradation reactions. The effect of time, temperature, and organic-to-aqueous phase ratio were investigated. The maximum furfural yields from xylose and birch hydrolysate liquor as feedstock under auto-catalyzed conditions when employing 2-sec-butylphenol (SBP) were 59 mol% and 54 mol%, respectively. In the monophasic system when using hydrolysate, 46% furfural was yielded. Based on a techno-economic analysis carried out for furfural, the total investment cost for a plant integrated with an existing pulp mill or bio-refinery is estimated as 14 M€. The minimum selling price of furfural found to be 1.62 € kg−1. With a furfural selling price of 1.93 € kg−1, the payback period is approximately 5 years and an internal rate of return (IRR) of 20.7% is achieved at the end of the project lifetime.
  • Furfural production from xylose in a bi-phasic set-up
    (2017-08-30) Gomez Millan, Gerardo; Hellsten, Sanna; Llorca, Jordi; Sixta, Herbert
     A4 Artikkeli konferenssijulkaisussa
    The production of furfural (FUR) from xylose was carried out using a biphasic batch reaction system. Isophorone and 2-methytetrahydrofuran (MTHF) have been used to extract FUR and enhance overall furfural yield by limiting its degradation to humins. The effect of time, temperature, and organic to aqueous ratio on xylose conversion and FUR yield were investigated. Experiments conducted at two temperatures (170 and 190 °C) were investigated in a stirred microwave-assisted batch reactor, which established the optimal conditions to obtain the highest FUR yield. The maximum FUR yields obtained from xylose were 82 mol% when using MTHF in 180 min (at 190 °C) and 43 mol% when using isophorone in 180 min (at 190 °C) with an aqueous to organic phase ratio of 5:1.
  • Furfural production in a biphasic system using a carbonaceous solid acid catalyst
    (2019) Gomez Millan, Gerardo; Phiri, Josphat; Mäkelä, Mikko; Maloney, Thaddeus; Balu, Alina; Pineda, Antonio; Llorca, Jordi; Sixta, Herbert
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The formation of furfural from xylose was investigated under heterogeneously catalyzed conditions with sulfated Starbon as a catalyst in a biphasic system. The experiments were perfomed based on the basis of a statistical experimental design. The variables considered were time, temperature and the ratio of aqueous to organic phase. The results indicate that sulfated Starbon is an effective solid acid catalyst for furfural formation. Starbon was characterised by scanning electron microscopy, N2-physisorption, thermogravimetric analysis, diffuse reflectance infrared Fourier transform, Raman spectroscopy and titration with pyridine. The maximum furfural yield and selectivity of 70 mol% were achieved with complete xylose conversion under the optimum experimental conditions. The present paper suggests that functionalized Starbon can be employed as an efficient solid acid catalyst that has significant hydrothermal stability and can be reused for several cycles to produce furfural from xylose.
  • Recent advances in the catalytic production of platform chemicals from holocellulosic biomass
    (2019-04-18) Gomez Millan, Gerardo; Hellsten, Sanna; Llorca, Jordi; Luque, Rafael; Sixta, Herbert; Balu, Alina
     A2 Katsausartikkeli tieteellisessä aikakauslehdessä
    This Review discusses novel catalytic pathways of lignocellulosic biomass to value-added chemicals including biomass-derived sugar alcohols, organic acids, furans and biohydrocarbons. These production approaches are undertaken by biological, chemical and thermochemical transformations or a combination of them. Nevertheless, the majority of research in this area is focused on the design of heterogeneous catalysts to convert value-added products from holocellulosic biomass. Biorefineries represent the peak of biomass processes in order to produce valuable chemicals and liquid fuels avoiding the utilization of corroding and toxic elements. The aim of the present Review is to offer the readers a broad overview of recent holocellulosic-based chemical and fuels production technologies via heterogeneous catalysis. There is also an overview of the economic aspects to efficiently produce these platform chemicals at industrial scale. To summarize this Review, an outlook and conclusions of the reported processes to date is provided.
  • A study of the decomposition products of furfural, xylose and isophorone using NMR
    (2019-03-24) Gomez Millan, Gerardo; King, Alistair W.T.; Llorca, Jordi; Sixta, Herbert
     A4 Artikkeli konferenssijulkaisussa
    In recent years we have witness lots of activity to upgrade sugars contained in lignocellulosic biomass into ethanol and other value-added chemicals. An interesting catalytic route, namely the dehydration of sugars (pentoses and hexoses found in lignocellulose) to furans, is considered one of the most promising routes for the production of platform chemicals and fuels [1]. One attractive furanic compound, furfural (FUR), has been identified as a direct or indirect feedstock to more than 80 chemicals [2,3]. The current FUR production uses mineral acids at approximately 200 °C, providing around 50 mol% yield [4]. Low yields in this process are mainly due to FUR decomposition with other compounds via resinification and condensation producing insoluble polymers (humins) [5]. A practical way to inhibit the formation of humins is to extract the FUR instantaneously from the aqueous solution into an organic phase [6]. In this study, the production of FUR from xylose was carried out using a biphasic batch reaction system. Isophorone was used to extract FUR from the aqueous phase to enhance the overall FUR yield by limiting its degradation. Due to their water-immiscibility nature, this organic solvent do not require salt addition, which is a significant advantage over other water-miscible organic solvents. The effect of time, temperature and organic-to-aqueous ratio on xylose conversion and FUR yield were investigated. Experiments conducted at three temperatures (170, 190 and 210 °C) were studied in a stirred microwave-assisted batch reactor, which established the optimal conditions to obtain the highest FUR yield. The maximum FUR yields obtained from xylose was 48 mol% when using isophorone with an aqueous to organic phase ratio of 1:1. In the present work from isophorone, it demonstrates a low selectivity towards FUR (and thus low FUR yield) with decomposition. This suggests that FUR undergoes decomposition reactions, potentially including isophorone as a co-reactant. Alternatively, the rate of degradation of FUR may be increased by an increasing content of water at temperatures approaching 200 °C. These possibilities were investigated by NMR analysis of the degradation of FUR: isophorone molar ratios of 1:1 and 1:10 at 190 °C over 30 min (Figure 1). Potential mechanisms for this degradation might be, for example, Diels-Alder cycloaddition (isophorone as hindered dienophile), Aldol condensation (isophorone C6 reacting as nucleophile at the FUR aldehyde), Baylis-Hillman reaction (isophorone C2 reacting as nucleophile at the FUR aldehyde) and Michael addition (isophorone C3 as α-β unsaturated electrophile). Other reactivity may of course be possible [7-9].