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Highly active and stable Ni–W/SiO2 catalyst derived from W incorporated on Ni phyllosilicate for deoxygenation of triglycerides into green biofuel range hydrocarbons
(2025-10-01)
Praikaew, Wanichaya
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Prameswari, Jedy
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Ratchahat, Sakhon
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Chaiwat, Weerawut
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Sakdaronnarong, Chularat
Highly active and stable Ni–W/SiO<inf>2</inf> catalyst derived from W incorporated into Ni phyllosilicate (Ni-PS) was prepared by the ammonia evaporation (AE) method, and benchmarked with the catalyst prepared by the impregnation method (IM). Their catalytic activities were evaluated for deoxygenation of triglycerides into green biofuel-range hydrocarbons. The Ni-PS structure demonstrated a large surface area with strong interaction between Ni2+ and SiO<inf>2</inf>, resulting from the incorporation of Ni2+ into the silica framework, which led to highly dispersed Ni⁰ after H<inf>2</inf> reduction. Additionally, the H<inf>2</inf> adsorption and desorption capabilities, together with a substantial quantity of Lewis acid sites, were advantageous features of Ni-PS catalysts compared to Ni-IM and 5 W/Ni-IM catalysts. Ex situ and in situ structural characterizations revealed the generation of Ni⁰ and W⁰ states, along with remaining W4+ species after H<inf>2</inf> reduction. The 5 W/Ni-AE catalyst exhibited stable performance up to 60 h on stream, producing consistent yields of 30 % jet fuel and 40 % diesel, which was attributed to its high porosity, small Ni⁰ particle sizes, enhanced H<inf>2</inf> adsorption–desorption capacities, and abundant Lewis acid sites. Consequently, the heterogeneous 5 W/Ni-AE catalyst shows significant practical relevance for generating green biofuel from oil-derived feedstock in sustainable biorefineries.
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Deoxygenation of heptanoic acid to hexene over cobalt-based catalysts: A model study for α-olefin production from renewable fatty acid
(2020-07-25)
Phichitsurathaworn, Ploynisa
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Choojun, Kittisak
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Poo-arporn, Yingyot
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Sooknoi, Tawan
Deoxygenation of heptanoic acid, a model compound, over bimetallic cobalt (Co-Pt, Co-Au, Co-Pd, Co-Ru) supported silica catalysts, was examined for α-olefin production. The catalysts were prepared by conventional impregnation of the metal precursors on silica and characterized by XRF, TEM, H<inf>2</inf>-TPR, acetic acid-TPD, and XANES. Catalytic testing was performed in a fixed-bed flow reactor under atmospheric H<inf>2</inf> pressure. Monometallic cobalt catalysts yielded mainly 1-hexene, but rapid deactivation was observed. Incorporation of 0.5%wt secondary metal, particularly Pt, increases activity and stability under H<inf>2.</inf> A relatively higher olefin/paraffin ratio can be obtained from the reaction over 5%Co+0.5%Pt/SiO<inf>2</inf> when compared to that with higher Pt loading. The co-impregnation method offers Co-Pt catalysts with stability higher than that prepared by the sequential impregnation method. Over cobalt-based catalysts, the deoxygenation is proposed to proceed via reduction of heptanoic acid to heptanal that is an intermediate for decarbonylation to hexene; while other side reactions are suppressed.
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Extending the basic function of lattice oxygen in lepidocrocite titanate – The conversion of intercalated fatty acid to liquid hydrocarbon fuels
(2017-12-01)
Maluangnont, Tosapol
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Arsa, Pornanan
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Sooknoi, Tawan
We report herein the basicity of the external and internal lattice oxygen (O<inf>L</inf>) in lepidocrocite titanates with respect to CO<inf>2</inf> and palmitic acid, respectively. Several compositions have been tested with different types of the metal M aliovalently (co)substituted for Ti, K<inf>0.8</inf>[M<inf>y</inf>Ti<inf>2−y</inf>]O<inf>4</inf> (M = Li, Mg, Fe, Co, Ni, Cu, Zn, Cu/Ni and Cu/Zn). The low CO<inf>2</inf> desorption peak temperature (70–100 °C) suggests that the external O<inf>L</inf> sites are weakly basic similar to TiO<inf>2</inf>. However, the internal O<inf>L</inf> sites are sufficiently basic to deprotonate palmitic acid, forming the intercalated potassium palmitate at the interlayer spaces. The latter serves as a two-dimensional (2D) molecular reactor for the production of liquid hydrocarbon fuels via deoxygenation under atmospheric N<inf>2</inf>. A relationship has been observed between the yield of the liquid products vs the partial charge of the lattice oxygen (δ<inf>O</inf>). Since the deoxygenation pathway is highly dependent on the metal substitution, the redox-active sites might also play some roles. The co-substituted K<inf>0.8</inf>[Cu<inf>0.2</inf>Ni<inf>0.2</inf>]Ti<inf>1.6</inf>O<inf>4</inf> produced ~68.0% yield of the liquid products, with ~ 51% saturated and ~ 15% unsaturated C<inf>15</inf> hydrocarbons at 350 °C.
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Production of liquid fuel from palmitic acid over nanocrystalline CeO2-based catalysts with minimal use of H2
(2017-01-01)
Maluangnont, Tosapol
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Dararat, Chalinee
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Kulrat, Teerapong
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Soontontaweesub, Surachet
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Anothaiwalaikul, Thitima
The deoxygenation of palmitic acid into diesel-range hydrocarbons can be promoted over nanocrystalline ceria-based catalysts under atmospheric N<inf>2</inf> or 10% H<inf>2</inf>/N<inf>2</inf> in a fixed-bed flow reactor at 400 °C. Oxygen vacancy sites are active for ketonization of palmitic acid to C<inf>31</inf> ketone and also subsequent cracking of the formed ketone to hydrocarbons. The 22–31% selectivity of C<inf>9</inf> to C<inf>17</inf> liquid hydrocarbons can be achieved at 100% palmitic acid conversion. The deoxygenation under N<inf>2</inf> can be facilitated, presumably by hydrogen transfer from coke precursors. Catalytic activity of ceria-based catalysts can be tuned by pretreatment conditions, type of a carrier gas, or lattice modification.
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Effect of extra-framework cesium on the deoxygenation of methylester over CsNaX zeolites
(2011-12-15)
Danuthai, Tanate
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Sooknoi, Tawan
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Jongpatiwut, Siriporn
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Rirksomboon, Thirasak
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Osuwan, Somchai
The deoxygenation of methyl octanoate has been investigated over Cs-containing NaX zeolite catalysts at atmospheric pressure with He carrier gas and methanol as a co-feed. By varying the preparation procedures, different amounts of extra-framework Cs were left on the catalyst. The presence of extra-framework Cs affects the acid-basic characteristics of the catalysts and consequently their activity, stability, and particularly the product selectivity. That is, when the amount of extra-framework Cs increases, the corresponding increase in basicity enhances decarbonylation activity as well as catalyst stability. In this case, the deoxygenation of methyl octanoate on CsNaX catalysts was found to yield heptenes and hexenes as main products via surface decomposition of octanoate-like species. When the amount of extra-framework Cs was reduced, the hexene yield readily increased. The enhancement in hexene production can be ascribed to both, a decreased basicity that reduces decarbonylation and to a greater space available within the zeolite cavity for formation of a rather bulky cyclic-like intermediate that leads to hexene. In addition, weakly acidic sites, generated after the excess Cs was removed, resulted in relatively higher yield of inner-olefin product. When Cs was not present in the catalyst (i.e., NaX), other products such as aromatics and coupling compounds were observed. These compounds are less desirable for transportation fuel applications. © 2011 Elsevier B.V. All rights reserved.
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A comparison of the reactivities of propanal and propylene on HZSM-5
(2010-05-04)
Hoang, Trung Q.
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Zhu, Xinli
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Sooknoi, Tawan
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Resasco, Daniel E.
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Mallinson, Richard G.
The reactivities of propanal and propylene have been compared over HSZM-5 zeolites (Si/Al = 45 and 25). Propanal is found to be much more reactive than propylene and to form mostly 2-methyl-2-pentenal and C<inf>9</inf> aromatics as early products in the reaction network. Propylene, in contrast, requires more severe conditions to form C<inf>6</inf> and C<inf>7</inf> aromatics. It is proposed that propanal undergoes acid-catalyzed aldol condensation to form 2-methyl-2-pentenal. This dimer undergoes further condensation to form the aldol trimer, which subsequently dehydrates and cyclizes into C<inf>9</inf> aromatics. In contrast, it is well known that propylene, like other olefins, undergoes aromatization via oligomerization and formation of a hydrocarbon pool. While in the conversion of propanal, propylene is also produced, it appears that it does not play a major role in the formation of aromatics under conditions of shorter space times and lower temperatures, at which propanal produces aromatics in significant amounts. © 2010 Elsevier Inc. All rights reserved.
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Catalytic deoxygenation of benzaldehyde over gallium-modified ZSM-5 zeolite
(2009-11-15)
Ausavasukhi, Artit
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Sooknoi, Tawan
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Resasco, Daniel E.
The deoxygenation of benzaldehyde has been investigated over gallium-modified ZSM-5 catalysts. In the absence of H<inf>2</inf>, Ga/HZSM-5 catalyzes benzaldehyde decarbonylation resulting in benzene and CO. The active sites for this reaction are the strong Brønsted acid sites. In the presence of H<inf>2</inf>, the main product is toluene. It is believed that Ga cationic species (Ga+ / GaH<inf>2</inf>+) generated during H<inf>2</inf> reduction can promote the hydrogenation/hydrogenolysis reactions that give toluene and water. In the absence of H<inf>2</inf>, toluene can only be observed in transient experiments when the Ga/HZSM-5 catalysts are reduced. It is suggested that the GaH<inf>2</inf>+ species generated under H<inf>2</inf> play an important role in the hydrogenation/hydrogenolysis. However, they readily decompose to Ga+ in the absence of H<inf>2</inf>. The addition of water to the feed modifies the catalytic activity and selectivity of Ga/HZSM-5 catalysts. On the one hand, water generates additional Brønsted acid sites from the reaction of extra-framework Ga with chemisorbed water (GaO(OH)) and with defect hydroxyls of the zeolite framework (GaOHSi). These additional sites enhance the production of benzene but decrease the production of toluene, due to a decrease in the density of reduced Ga cationic species. © 2009 Elsevier Inc. All rights reserved.

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