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Title:Catalytic hydro(deoxy)genation of furfural and modelling of its reaction kinetics
Authors:ID Šivec, Rok (Author)
ID Grilc, Miha (Mentor) More about this mentor... New window
ID Huš, Matej (Mentor) More about this mentor... New window
Files:.pdf Rok_Sivec.pdf (9,23 MB)
MD5: 4179F90EB2DBCBAAB29DF70662EBCFE0
 
Language:English
Work type:Not categorized
Organization:FPŠ - Graduate School
Abstract:In recent decades, there has been a growing interest in producing biofuels and biochemicals from renewable sources. Furfural stands as one of the ligno(hemi)cellulosic biomass derived platform chemical, which can be transformed into numerous value-added products. The goal of this PhD was to systematically study hydrotreatment reactions of furfural under varying operating conditions and to gain insights into the reaction mechanism and kinetics. An extensive experimental and computational study of hydrogenation, hydrodeoxygenation, oligomerisation and etherification of furfural in a three-phase batch reactor was performed. The goals were divided into three consecutive objectives. In the first part, hydrotreatment of furfural over Pd/C catalyst under various reaction conditions, including the solvent selection (solventless conditions, tetrahydrofuran, isopropanol), atmosphere (nitrogen, hydrogen), temperature (100–200 °C), pressure (25–75 bar) and stirring speed, was studied. A reaction pathway network and a micro-kinetic model were developed, incorporating thermodynamics (hydrogen solubility), mass transfer, adsorption, desorption, and surface reactions. These phenomena and their contribution to the surface coverages, TOF’s and global reaction rates were studied. The hydrogen presence on the catalyst surface was found to influence the main reaction pathway, leading to ring, aldehyde group or full hydrogenation. In the second part, various monometallic catalysts (Pd/C, Pt/C, Re/C, Ru/C, Rh/C, Ni/C, Cu/C) were tested at 100 -200 °C with 60 bar of hydrogen and tetrahydrofuran as solvent. A generalized reaction pathway network was developed. H2 temperature-programmed reduction (H2-TPR) and CO temperature-programmed desorption (CO-TPD) were conducted, and a regression analysis of the results was subsequently performed by numerical modelling and optimisation. The obtained adsorption and desorption kinetic parameters for active metallic sites were further used in a generalized micro-kinetic model, applicable to all tested catalysts. Pd/C exhibited high activity and non-selective hydrogenation of furfural, while other catalysts showed selective aldehyde group hydrogenation followed by deoxygenation, consistent with density functional theory (DFT) calculations. Ru/C uniquely produced 2 methyltetrahydrofuran and ring-opening products at 200 °C. In silico optimization of reaction conditions for promising catalysts ((Pd/C, Pt/C, Re/C, Ni/C) aimed to maximize the yield of the target product. In the third part, the influence of support on catalytic activity was studied. Hydrotreatment of furfural over Pd/Al2O3, Pd/SiO2, Ru/Al2O3, Ru/SiO2, Ni/Al2O3, and Ni/SiO2 was performed between 150 - 200 °C, using 60 bar of hydrogen and tetrahydrofuran as solvent. The strength and rate of adsorption and desorption to/from acidic, metallic and interface site structures were determined, using H2-TPR, CO-TPD and NH3-TPD and subsequent regression analysis of the results by numerical modelling and optimisation. The resulting parameters were sequentially used in the generalized micro-kinetic model to quantify the contribution of the active metal (Ni, Pd, or Ru), support (Al2O3 or SiO2), interphase sites and their relationship on catalyst activity and selectivity. Evaluation of morphological and structural characteristics, adsorption/desorption and intrinsic reaction kinetics has indicated that the coverage of acidic sites (on alumina or silica) facilitated yielding ring hydrogenation and inhibited deoxygenation, decarbonylation and cyclic compound opening. The rates for aromatics or aldehyde functional groups were, nonetheless, affected in a different order. The used and developed methods and findings of this PhD offer useful guidelines for transforming furfural into high-value chemicals through catalytic hydrotreatment, with significant implications for future research and industrial applications.
Keywords:Lignocellulosic biomass, furfural, catalytic hydrogenation, micro-kinetic mass transfer model, reaction kinetics, first-principle methods, furfuryl alcohol, tetrahydrofurfuryl alcohol.
Place of publishing:Nova Gorica
Year of publishing:2024
Publication date in RUNG:08.11.2024
Views:146
Downloads:2
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Licences

License:CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Link:http://creativecommons.org/licenses/by-nc-nd/4.0/
Description:The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
Licensing start date:03.11.2024

Secondary language

Language:Slovenian
Title:Katalitična hidro(deoksi)genacija furfurala in modeliranje reakcijske kinetike
Abstract:V zadnjih desetletjih se povečuje zanimanje za proizvodnjo biogoriv in biokemikalij iz obnovljivih virov. Furfural je pomembna platformna kemikalija, pridobljena iz ligno(hemi)celulozne biomase, katero je mogoče pretvoriti v številne produkte z dodano vrednostjo. V sklopu tega doktorskega dela sem sistematično preučeval in optimiziral reakcije furfurala z vodikom pri različnih procesnih pogojih in pridobil vpogled v reakcijski mehanizem. Ta obsežna eksperimentalna in računska študija hidrogenacije, hidrodeoksigenacije, oligomerizacije in eterifikacije furfurala v trifaznem šaržnem reaktorju je bila razdeljena v tri zaporedne dele. Cilj prvega dela je bila pretvorba furfurala z vodikom preko Pd/C katalizatorja pri različnih procesnih pogojih, vključno z izbiro topila (odsotnost topila, tetrahidrofuran, izopropanol), atmosfere (dušik, vodik), temperature (100–200 °C), tlaka (25–75 bar) in hitrosti mešanja. Razvil sem shemo reakcijskih poti in mikro-kinetični model, ki vključuje termodinamiko (topnost vodika), prenos mase, adsorpcijo, desorpcijo in površinske reakcije. Preučeval sem vpliv teh pojavov in njihov prispevek na površinsko pokritost, hitrost pretvorbe in na globalne hitrosti reakcij. Prisotnost vodika na površini katalizatorja močno vpliva na reakcijsko pot, ki vodi do hidrogenacije obroča, aldehidne skupine ali do popolne hidrogenacije. V drugem delu sem testiral različne eno-kovinske katalizatorje (Pd/C, Pt/C, Re/C, Ru/C, Rh/C, Ni/C, Cu/C) pri 100 °C, 150°C in 200 °C, z uporabo vodika pod tlakom 60 bar in topila tetrahidrofuran. Razvil sem splošno shemo reakcijskih poti. Izvedel sem temperaturno programirano redukcijo H2 (H2-TPR) in temperaturno programirano desorpcijo CO (CO-TPD). Dobljene rezultate sem ovrednotil z regresijsko analizo, numeričnim modeliranjem in optimizacijo. Pridobljene kinetične parametre adsorpcije in desorpcije za aktivna kovinskih mesta sem nato uporabil v posplošenem mikro kinetičnem modelu za vse testirane katalizatorje. Pd/C je izkazal visoko aktivnost ter neselektivno hodrogenacijo furfurala, medtem ko so ostali katalizatorji selektivno hidrogenirali aldehidno skupino, kateri je sledila deoksigenacija, kar je skladno z izračuni po teoriji gostotnega funkcionala (DFT). Ru/C je edini katalizator, ki je pri 200 °C omogočil proizvodnjo 2-metiltetrahidrofurana in produktov, ki nastanejo z odprtjem obroča. Izvedel sem tudi in silico optimizacijo procesnih pogojev za obetavne katalizatorje (Pd/C, Pt/C, Re/C, Ni/C), z namenom pridobitve optimalnega izkoristka ciljnega produkta. V tretjem delu sem preučeval vpliv nosilca na katalitično aktivnost. Testiral sem katalizatorje Pd/Al2O3, Pd/SiO2, Ru/Al2O3, Ru/SiO2, Ni/Al2O3, in Ni/SiO2 pri 150 °C, 175 °C in 200 °C, z uporabo vodika pod tlakom 60 bar in topila tetrahidrofuran. Na podlagi temperaturno programirane redukcije H2 (H2 TPR), temperaturno programirane desorpcije CO (CO-TPD) in NH3 (NH TPD), ter regresijske analize rezultatov z numeričnim modeliranjem in optimizacijo, sem določil parametre adsorpcije in desorpcije na/iz kislih mest, kovinskih mest ter vmesnih struktur. Pridobljene parametre sem nato uporabil v posplošenem mikro-kinetičnem modelu, s katerim sem ovrednotil prispevek aktivne kovine (Ni, Pd ali Ru), nosilca (Al2O3 ali SiO2), vmesnih struktur in njihov skupni vpliv na aktivnost in selektivnost. Na podlagi izmerjenih morfoloških in strukturnih značilnosti, adsorpcije/desorpcije ter kinetike sem ugotovil, da prisotnost kislih mest (na Al2O3 ali SiO2) olajša hidrogenacijo obroča ter zavira deoksigenacijo, dekarbonilacijo in odpiranje obroča. Kljub temu, je prisotnost kislih mest (na Al2O3 ali SiO2) vplivala na hitrost hidrogenacije obroča ali aldehidne skupine v različnem vrstnem redu. Uporabljene ter razvite metode in ugotovitve, ki so rezultat tega doktorskega dela, so pomembne za prihodnje akademske in industrijske raziskave ter nudijo uporabne smernice za pretvorbo furfurala v produkte z dodano vrednostjo.
Keywords:Lignocelulozna biomasa, furfural, katalitska hidrogenacija, mikro kinetični model s prenosom mase, reakcijska kinetika, kvantnokemijski izračuni iz prvih principov, furfuril alkohol, tetrahidrofurfuril alkohol.


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