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  • 1.
    Ahlkvist, Johan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Samikannu, Ajaikumar
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Larsson, William
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wärnå, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo, Finland.
    Salmi, Tapio
    Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo, Finland.
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo, Finland.
    Reaction Network upon One-pot Catalytic Conversion of Pulp2013In: / [ed] Sauro Pierucci, Jiří J. Klemeš, AIDIC - associazione italiana di ingegneria chimica, 2013, Vol. 32, p. 649-654Conference paper (Refereed)
    Abstract [en]

    Nordic sulphite and sulphate (Kraft) cellulose originating from Nordic pulp mills were used as raw materials in the catalytic synthesis of green platform chemicals, levulinic and formic acids, respectively. The catalyst of choice used in this study was a macro-porous, cationic ion-exchange resin Amberlyst 70 for which the optimal reaction conditions leading to best yields were determined. For this system, maximum yields of 53 mol-% and 57 mol-% were obtained for formic and levulinic acid, respectively. The reaction network of the various chemical species involved was investigated and a simple mechanistic approach involving first order reaction kinetics was developed. The prototype model was able to describe the behaviour of the system in a satisfactory manner.

  • 2.
    Ahlkvist, Johan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wärnå, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University,Turku, Finland.
    Salmi, Tapio
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. 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 acids2016In: Reaction Kinetics, Mechanisms and Catalysis, ISSN 1878-5190, E-ISSN 1878-5204, Vol. 119, no 2, p. 415-427Article in journal (Refereed)
    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.

  • 3.
    Bukhanko, Natalia
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Samikannu, Ajaikumar
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Larsson, William
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Shchukarev, Andrey
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Leino, Anne-Riikka
    Microelectronics and Materials Physics Laboratories, University of Oulu, Finland.
    Kordas, Krisztian
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Microelectronics and Materials Physics Laboratories, University of Oulu, Finland.
    Wärnå, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Finland.
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Finland.
    Continuous gas phase synthesis of 1-ethyl chloride from ethyl alcohol and hydrochloric acid over Al2O3-based catalysts: the ‘green’ route2013In: ACS Sustainable Chemistry & Engineering, Vol. 1, no 8, p. 883-893Article in journal (Refereed)
    Abstract [en]

    The synthesis of 1-ethyl chloride in the gas-phase mixture of ethanol and hydrochloric acid over ZnCl2/Al2O3 catalysts was studied in a continuous reactor using both commercial and tailor-made supports. The catalytic materials were characterized by the means of structural (XPS, TEM, XRD, and BET) and catalytic activity (selectivity and conversion) measurements. The reaction parameters such as temperature, pressure, and feedstock flow rates were optimized for the conversion of ethanol to ethyl chloride. The new tailor-made highly porous Al2O3-based catalyst outperformed its commercial counterpart by exhibiting high conversion and selectivity (98%) at the temperature of 325 °C. Long-term stability tests (240 h) confirmed the excellent durability of the tailor-made alumina catalysts. The process demonstrated here poses an efficient and economic “green” large-scale on-site synthesis of this industrially important reactant in industry, where bioethanol is produced and 1-ethyl chloride is necessary, e.g., for ethylation of cellulose and synthetic polymer products. On-site in situ production of ethyl chloride avoids the problems associated with the transportation and storage of toxic and flammable 1-ethyl chloride.

  • 4.
    Bukhanko, Natalia
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wärnå, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FIN-20500, Turku/Åbo, Finland.
    Samikannu, Ajaikumar
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FIN-20500, Turku/Åbo, Finland.
    Kinetic modeling of gas phase synthesis of ethyl chloride from ethanol and HCl in fixed bed reactor2016In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 142, p. 310-317Article in journal (Refereed)
    Abstract [en]

    Kinetic modeling of gas-phase synthesis of ethyl chloride from ethanol and hydrochloric acid over high porous Al2O3 and 2 wt% ZnCl2/Al2O3 catalysts was studied in a continuous plug flow reactor in the temperature range of 200–325 °C. Two rival kinetic models were proposed that both describe the kinetics well. The kinetic parameters of the reaction were determined and activation energy values for ethyl chloride formation from ethyl alcohol and diethyl ether reactions were calculated.

  • 5.
    Golets, Mikhail
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Samikannu, Ajaikumar
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mohln, M.
    University of Oulu, Oulu, Finland.
    Wärnå, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Åbo Akademi University, Åbo-Turku, Finland.
    Rakesh, S.
    Department of Chemistry, Podhigai College of Engineering and Technology, Tamilnadu, India.
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Åbo Akademi University, Åbo-Turku, Finland.
    Continuous production of the renewable ρ-cymene from α-pinene2013In: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 307, p. 305-315Article in journal (Refereed)
    Abstract [en]

    The aim of this work was to demonstrate the feasibility to produce ρ-cymene, an important commodity chemical, in a continuous, one-pot reaction system from abundant α-pinene, available e.g. as a by-product of pulping industry. The isomerization reactions of α-pinene over bimetallic heterogeneous catalysts, 3 and 5 wt% Pd–Zn (1:1, 1:4, 4:1, 1:0, and 0:1), supported on Al-SBA15 were studied. The principal reaction products were identified as ρ- and m-cymenes, limonene, camphene, and ρ-menthene, respectively. The highest concentration of ρ-cymene reached 77 wt% under the optimized reaction conditions: 300 °C and α-pinene feed of 0.03 mL/min. Two main reaction pathways toward ρ- and m-cymenes were described, and a mechanistic kinetic model, based on a plausible reaction network in line with Langmuir–Hinshelwood approach, was developed. The catalyst characterization revealed the reduction in Pd(II) sites, catalyst coking, and decline of surface area over the course of time. The catalyst recovery and reuse was addressed.

  • 6.
    Konwar, Lakhya Jyoti
    et al.
    Åbo Akademi University, Åbo-Turku, Finland.
    Wärnå, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Åbo Akademi University, Åbo-Turku, Finland.
    Mäki-Arvela, Päivi
    Åbo Akademi University, Åbo-Turku, Finland.
    Kumar, Narendra
    Åbo Akademi University, Åbo-Turku, Finland.
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Åbo Akademi University, Åbo-Turku, Finland.
    Reaction kinetics with catalyst deactivation in simultaneous esterification and transesterification of acid oils to biodiesel (FAME) over a mesoporous sulphonated carbon catalyst2016In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 166, p. 1-11Article in journal (Refereed)
    Abstract [en]

    In this work, a careful analysis of the reaction kinetics upon simultaneous esterification and transesterification of acidic oils over a mesoporous sulphonated carbon catalyst is discussed. A batch reactor system was used and the synthesized carbon catalyst were characterized by N2-physisorption, transmission electron microscopy, elemental analysis and NH3-TPD. A second order pseudo-homogeneous kinetic model was proposed which explained the experimental results obtained for three different feedstock oils with ⩾98% accuracy. The rate constants (k), activation energies (Ea) and equilibrium constants (Keq) of the individual reactions were determined by regression analysis which confirmed that the reaction steps were kinetically controlled and not limited by inter-particle diffusion or external mass transfer limitations (Ea > 25 kJ mol−1). Furthermore, the composition feedstock was found to have a distinct effect on the solubility of methanol and oil phase which influenced k, Keq and Ea values, eventually determining the final biodiesel (FAME) yield. To account for the loss of activity upon catalyst reuse, a deactivation model was also proposed which explained our results with ∼94% accuracy. In fact, the loss of activity was accounted for by incorporating a concentration-independent ‘deactivation constant’ kd in the reaction rate equations. Moreover, under optimized reaction conditions (120 °C and 20:1 methanol-to-FFA molar ratio), FAME yields up to 79–91 wt% could be obtained in one step process from oils containing 21–41 wt% FFA.

  • 7. Leveneur, Sebastien
    et al.
    Zheng, Junliu
    Taouk, Bechara
    Burel, Fabrice
    Wärnå, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Salmi, Tapio
    Interaction of thermal and kinetic parameters for a liquid-liquid reaction system: Application to vegetable oils epoxidation by peroxycarboxylic acid2014In: Journal of the Taiwan Institute of Chemical Engineers / Elsevier, ISSN 1876-1070, E-ISSN 1876-1089, Vol. 45, no 4, p. 1449-1458Article in journal (Refereed)
    Abstract [en]

    A mathematical model was developed to analyze an exothermic liquid-liquid reaction system using epoxidation of oleic acid by peroxyformic acid formed in situ as an example. Kinetic and thermal parameters were included, mass transfer parameters were eliminated from the model and evaporation/condensation was taken into account. A calorimetric semi-batch reactor under isoperibolic mode was used in the experimental work. Different initial aqueous-phase concentrations of H2O2 [6.5-8.8 mol/l], water [44-45 mol/l], molar flow rate of formic acid [0.02-0.54 mol/min], initial reaction temperature [50-70 degrees C] and amount of organic phase [34-46 wt.%] were studied. A non-linear regression method was used to estimate kinetic (e.g., rate constant at average temperature and activation energy) and thermal parameters (e.g., reaction enthalpy) of the epoxidation and ring-opening reactions. The standard reaction enthalpy changes were estimated to be -116 kJ/mol for epoxidation reaction and -50 kJ/mol for the ring opening. (C) 2014 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

  • 8. Murzin, Dmitry Yu.
    et al.
    Kusema, Bright
    Murzina, Elena V.
    Aho, Atte
    Tokarev, Anton
    Boymirzaev, Azamat S.
    Wärnå, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Department of Chemical Engineering, Åbo Akademi University.
    Dapsens, Pierre Y.
    Mondelli, Cecilia
    Perez-Ramirez, Javier
    Salmi, Tapio
    Hemicellulose arabinogalactan hydrolytic hydrogenation over Ru-modified H-USY zeolites2015In: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 330, p. 93-105Article in journal (Refereed)
    Abstract [en]

    The hydrolytic hydrogenation of hemicellulose arabinogalactan was investigated in the presence of protonic and Ru (1-5 wt.%)-modified USY zeolites (Si/Al ratio = 15 and 30). The use of the purely acidic materials was effective in depolymerizing the macromolecule into free sugars. While the latter partly dehydrated into 5-hydroxymethylfurfural and furfural, the generation of high molecular-weight compounds (aggregates of sugars and humins) was not favored, in contrast to previous evidences over beta zeolites. Application of the bifunctional Ru/USY catalyst, comprising well-dispersed metallic nanopartides on the aluminosilicate support, resulted in the formation of galactitol and arabitol, in the suppression of dehydration side products, and further inhibition of polymerization reactions, which only yielded low molecular-weight oligomers. Detailed analysis of the reaction pathways as well as kinetic modeling of hydrolytic hydrogenation was performed with an advanced reaction mechanism.

  • 9.
    Riittonen, T.
    et al.
    Process Chemistry Centre, Åbo Akademi University, 20500, Turku, Finland.
    Salmi, T.
    Process Chemistry Centre, Åbo Akademi University, 20500, Turku, Finland.
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wärnå, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Process Chemistry Centre, Åbo Akademi University, 20500, Turku, Finland.
    Direct Synthesis of 1-Butanol from Ethanol in a Plug Flow Reactor: Reactor and Reaction Kinetics Modeling2014In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 57, no 17-20, p. 1425-1429Article in journal (Refereed)
    Abstract [en]

    Bio-ethanol is well known for its use as a gasoline additive. However, it can be blended in low portions to traditional gasoline although it has a corrosive nature. By taking advantage of modern continuous reactor technology and heterogeneous alumina catalysts, ethanol can be upgraded to 1-butanol in fixed beds. Butanol has more feasible properties as fuel component in comparison to ethanol. Mathematical modeling of reaction kinetics revealed a simple kinetic model could be used to describe the complex reaction process on a Cu/alumina catalyst. The reaction kinetics model is based on five parallel reactions in which ethanol reacts to 1-butanol, acetealdehyde, ethyl acetate, diethyl ether and diethoxyethane, respectively.

  • 10. Rozmyslowicz, Bartosz
    et al.
    Kirilin, Alexey
    Aho, Atte
    Manyar, Haresh
    Hardacre, Christopher
    Wärnå, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Salmi, Tapio
    Murzin, Dmitry Yu.
    Selective hydrogenation of fatty acids to alcohols over highly dispersed ReOx/TiO2 catalyst2015In: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 328, p. 197-207Article in journal (Refereed)
    Abstract [en]

    Production of fatty alcohols through selective hydrogenation of fatty acids was studied over a 4% ReOx/TiO2 catalyst. Stearic acid was hydrogenated to octadecanol at temperatures and pressures between 180-200 degrees C and 2-4 MPa, with selectivity reaching 93%. A high yield of octadecanol was attributed to a strong adsorption of the acid compared to alcohol on the catalyst, which inhibits further alcohol transformation to alkanes. Low amounts (<7%) of alkanes (mainly octadecane) were formed during the conversion of stearic acid. However, it was found that the catalyst could be tuned for the production of alkanes. The reaction intermediates were octadecanal and stearyl stearate. Based on the reaction products analysis and catalyst characterization, a reaction mechanism and possible pathways were proposed.

  • 11. Salmi, Tapio
    et al.
    Murzin, Dmitry Yu
    Mäki-Arvela, Päivi
    Kusema, Bright
    Holmbom, Bjarne
    Willfor, Stefan
    Wärnå, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kinetic modeling of hemicellulose hydrolysis in the presence of homogeneous and heterogeneous catalysts2014In: AIChE Journal, ISSN 0001-1541, E-ISSN 1547-5905, Vol. 60, no 3, p. 1066-1077Article in journal (Refereed)
    Abstract [en]

    Kinetic models were developed for the hydrolysis of O-acetyl-galactoglucomannan (GGM), a hemicellulose appearing in coniferous trees. Homogeneous and heterogeneous acid catalysts hydrolyze GGM at about 90°C to the monomeric sugars galactose, glucose, and mannose. In the presence of homogeneous catalysts, such as HCl, H2SO4, oxalic acid, and trifluoroacetic acid, the hydrolysis process shows a regular kinetic behavior, while a prominent autocatalytic effect was observed in the presence of heterogeneous cation-exchange catalysts, Amberlyst 15 and Smopex 101. The kinetic models proposed were based on the reactivities of the nonhydrolyzed sugar units and the increase of the rate constant (for heterogeneous catalysts) as the reaction progresses and the degree of polymerization decreases. General kinetic models were derived and special cases of them were considered in detail, by deriving analytical solutions for product distributions. The kinetic parameters, describing the autocatalytic effect were determined by nonlinear regression analysis. The kinetic model described very well the overall kinetics, as well as the product distribution in the hydrolysis of water soluble GGM by homogeneous and heterogeneous catalysts. The modelling principles developed in the work can be in principle applied to hydrolysis of similar hemicelluloses as well as starch and cellulose.

    © 2014 American Institute of Chemical Engineers AIChE J, 60: 1066–1077, 2014

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