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  • 1.
    Ahlkvist, Johan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Wärnå, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University,Turku, Finland.
    Salmi, Tapio
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University,Turku, Finland.
    Heterogeneously catalyzed conversion of nordic pulp to levulinic and formic acids2016Inngår i: Reaction Kinetics, Mechanisms and Catalysis, ISSN 1878-5190, E-ISSN 1878-5204, Vol. 119, nr 2, s. 415-427Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herein, one-pot conversion of cellulose to platform chemicals, formic and levulinic acids was demonstrated. The catalyst selected was an affordable, acidic ion-exchange resin, Amberlyst 70, whereas the cellulose used was sulfite cellulose delivered by a Swedish pulp mill. Furthermore, in an attempt to better understand the complex hydrolysis network of the polysaccharide, kinetic experiments were carried out to pinpoint the optimal reaction conditions with an initial substrate concentration of 0.7–6.0 wt% and a temperature range of 180–200 °C. Higher temperatures could not be used due to the limitations in the thermal stability of the catalyst. Overall, maximum theoretical yields of 59 and 68 mol% were obtained for formic and levulinic acid, respectively. The parameters allowing for the best performance were reaction temperature of 180 °C and initial cellulose concentration of 0.7 wt%. After studying the behavior of the system, a simplified reaction network in line with a mechanistic approach was developed and found to follow first order reaction kinetics. A satisfactory fit of the model to the experimental data was achieved (97.8 % degree of explanation). The catalyst chosen exhibited good mechanical strength under the experimental conditions and thus, a route providing green platform chemicals from soft wood pulp from coniferous trees (mixture of Scots Pine and Norway Spruce) was demonstrated.

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  • 2. Konwar, Lakhya Jyoti
    et al.
    Mäki-Arvela, Päivi
    Kumar, Narendra
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Finland.
    Sarma, Anil Kumar
    Deka, Dhanapati
    Selective esterification of fatty acids with glycerol to monoglycerides over –SO3H functionalized carbon catalysts2016Inngår i: Reaction Kinetics, Mechanisms and Catalysis, ISSN 1878-5190, E-ISSN 1878-5204, Vol. 119, nr 1, s. 121-139Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    –SO3H containing carbon materials (sulfonated carbons) were successfully employed as heterogeneous catalysts upon the selective esterification of glycerol with lauric and oleic acids. The functionalized carbon catalysts outperformed zeolites H–Y, H-ZSM-5 and liquid H2SO4 with respect to activity and selectivity, thus producing commercially important monoglycerides with excellent selectivity (70–80 %), at fatty acid conversion levels of 80–95 %. Most importantly, upon use of these catalysts, significant improvements were obtained with respect to process parameters in comparison to the solid acids reported before: our reaction (1) required shorter reaction time (7–24 h), (2) operated at equimolar fatty acid-to-glycerol ratio, (3) could be employed at moderate reaction temperatures (100–125 °C) and (4) catalyst reused was feasible thus confirming the catalytic potential of sulfonated carbons for production of high concentration monoglycerides. Moreover, the experimental results also demonstrate the existence of strong effects of catalyst pore structure (shape selectivity) and surface hydrophilicity imposed to the reaction products similar to the reactivity selectivity trends observed for –SO3H functionalized silica catalysts reported in previous studies.

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