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483 results on '"Mäki-Arvela, Päivi"'

1. Dry Reforming of Methane over Mn-modified Ni-based Catalysts

Author

Manabayeva, Alua M., Mäki-Arvela, Päivi, Vajglová, Zuzana, Martinez-Klimov, Mark, Yevdokimova, Olha, Peuronen, Anssi, Lastusaari, Mika, Tirri, Teija, Baizhumanova, Tolkyn S., Kassymkan, Kaisar, Kaumenova, Gulnar N., Brodskiy, Alexandr R., Sarsenova, Rabiga O., Shorayeva, Kamshat A., Murzin, Dmitry Yu., and Tungatarova, Svetlana A.

Published
2024
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16. Dendritic ZSM-5 zeolites as highly active catalysts for the valorization of monoterpene epoxides.

Author

Gallego-Villada, Luis A., Cueto, Jennifer, Alonso-Doncel, María del Mar, Mäki-Arvela, Päivi, Alarcón, Edwin A., Serrano, David P., and Murzin, Dmitry Yu.

Subjects
STERIC hindrance, BRONSTED acids, CATALYTIC activity, X-ray diffraction, EPOXY compounds, PINENE
Abstract

Dendritic ZSM-5 zeolites were investigated in the isomerization of monoterpene epoxides, including limonene-1,2-epoxide (LE), α-pinene epoxide, and β-pinene epoxide, which yields high-value compounds used in fragrances, cosmetics, and pharmaceuticals. The fresh catalysts were thoroughly characterized using XRD, Ar physisorption, pyridine-FTIR, TEM, FTIR/DTBPyr, and 27Al MAS NMR. In comparison with conventional and hierarchical ZSM-5 materials, the dendritic zeolite with a crystallization time of 4 days (d-ZSM-5/4d) was the most active material, with a turnover frequency value of 4.4 min−1 for LE isomerization. Likewise, remarkable yields of dihydrocarvone (DHC, 63%, 70 °C, 2 h), campholenic aldehyde (72.4%, 70 °C, 5 min), and myrtanal (47.7%, 50 °C, 5 min) were obtained with this material that exhibited the largest mesopore/external surface area (360 m2 g−1), showing also the narrowest mesopore size distribution. A direct relationship was observed between the TOF values and the concentration of external Brønsted acid sites, showing the presence of strong steric/diffusional limitations that are greatly overcome with the dendritic zeolites. The lower reactivity of trans-LE compared to cis-LE was attributed to the larger steric hindrance of the oxygen atom. Exploration of the solvent influence revealed that the reaction rate of LE was favored by non-polar solvents, while highly selective DHC formation occurred in the solvents of medium polarity. The d-ZSM-5/4d sample was shown to be robust because catalytic activity could be completely recovered by air calcination. [ABSTRACT FROM AUTHOR]

Published
2024
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20. Synthesis of acrylic acid from methyl lactate over calcium phosphate catalysts in a fixed bed reactor: time-on-stream behavior and kinetic analysis.

Author

Aho, Atte, Mäki-Arvela, Päivi, Kumar, Narendra, Angervo, Ilari, Eränen, Kari, Wärnå, Johan, Salmi, Tapio, and Murzin, Dmitry Yu

Subjects
*ACRYLIC acid synthesis, *ACRYLIC acid, *FIXED bed reactors, *CALCIUM phosphate, *BEHAVIORAL assessment, *LACTATES, *CATALYSTS
Abstract

Transformation of methyl lactate to acrylic acid was investigated over Ca3(PO4)2, Ca2(P2O7) and their mixture in the temperature range of 250-425 °C. The initial concentration of methyl lactate in water was varied from 2 wt% to neat methyl lactate. The results showed that these phosphate catalysts did not contain any measurable amounts of either acid sites or basic sites. The best catalyst was Ca3(PO4)2 giving 62% selectivity to acrylic acid at 75% conversion at 400 °C using GHSV of 95280 h−1 and 2 wt% methyl lactate in the initial feed. This catalyst exhibited larger surface area in comparison to Ca2(P2O7). Elemental analysis revealed that some Ca leaching occurred during reaction, while in case of Ca2(P2O7) the calcium leaching was 3.4 fold higher than observed for Ca3(PO4)2. Long-term results over Ca3(PO4)2 showed that extensive catalyst deactivation occurred during the first 11 h time-on-stream, after which the activity dropped only slightly. In addition to kinetic studies with different parameters, also, kinetic modeling was performed and the activation energies for formation of different products were determined over different catalysts. [ABSTRACT FROM AUTHOR]

Published
2024
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31. Modeling of a bubble column for CO2 removal by absorption with NaOH.

Author

Michelson, Johan, Mäki-Arvela, Päivi, Rajala, Pasi, Hallapuro, Markus, Schmid, Daniel, Karlström, Oskar, Wärnå, Johan, and Murzin, Dmitry Yu

Subjects
*BUBBLE column reactors, *GAS mixtures, *ABSORPTION, *ALKALINE solutions, *SODIUM hydroxide, *CARBON dioxide adsorption, *BUBBLES
Abstract

CO2 capture experiments were carried out in a small-scale bubble column reactor using alkaline solutions of sodium hydroxide. The results of the experiments show that a higher NaOH content in the liquid phase and elevated CO2 concentrations in the gas mixture led to a higher CO2 removal efficiency. A mathematical model was developed to describe the CO2 absorption as a function of CO2 gas inlet and OH- concentrations at low CO2 and OH- concentrations. The CO2 uptake at high OH- concentrations (high pH) was accurately predicted by the model, whereas the CO2 uptake at lower OH- concentrations could not be predicted with the same accuracy. [ABSTRACT FROM AUTHOR]

Published
2024
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50. Co-processing of fossil feedstock with lignin-derived model compound isoeugenol over Fe-Ni/H-Y-5.1 catalysts

Author

Vajglová, Zuzana, Gauli, Bibesh, Mäki-Arvela, Päivi, Simakova, Irina L., Kumar, Narendra, Eränen, Kari, Tirri, Teija, Lassfolk, Robert, Peurla, Markus, Doronkin, Dmitry E., and Murzin, Dmitry Yu.

Subjects
Technology, Bio-fuel, Isoeugenol, ddc:540, Co-processing, Hydrodeoxygenation, Fe-Ni catalysts, Hexadecane, Physical and Theoretical Chemistry, Lignin-derivative, ddc:600, Catalysis
Abstract

Journal of catalysis 421, 101 - 116 (2023). doi:10.1016/j.jcat.2023.03.016, Co-processing of n-hexadecane with lignin derived isoeugenol as a model compound was investigated in this work using low-cost mono- and bimetallic iron and nickel supported on H-Y-5.1 zeolite. Different Fe-Ni metal ratios in the catalyst led to different reaction rates of processes and product distribution. The presence of just 0.26 wt% isoeugenol in the mixture with n-hexadecane made hydroisomerization-hydrocracking of the latter two-fold less active. Catalysts with smaller metal particle sizes, lower than 6 nm were more efficient pointing out on structure sensitivity. Extremely high activity in co-processing was obtained over 2 wt% Fe – 8 wt% Ni/H-Y-5.1 catalysts with the median metal particle size of 4.6 nm and metals-to-acid site ratio of 8.6. Fe catalyst were much less active in isoeugenol hydrodeoxygenation, while high cracking activity of hexadecane was observed in the presence of Ni. Alkylation of n-hexadecane was a feature of 8 wt% Fe – 2 wt% Ni/H-Y-5.1, whereas, over the 5 wt% Fe – 5 wt% Ni/H-Y-5.1 bifunctional catalyst no undesired oxygen-containing cyclic products were detected. This catalyst exhibited the highest hydrogen consumption according to temperature programmed desorption, which can serve as a marker for efficient hydrodeoxygenation. The spent catalysts contained ca 40 wt% of coke with predominantly aliphatic species., Published by Elsevier, Amsterdam [u.a.]

Published
2023

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