Deoxygenation Of Oleic Acid Research Articles

Deoxygenation of Oleic Acid Using Modified MCM-41 Supported Nickel-Tungstate Catalyst to Produce Renewable Biofuel Liquid Alkanes: Kinetic Study

Deoxygenation of Oleic Acid Using Modified MCM-41 Supported Nickel-Tungstate Catalyst to Produce Renewable Biofuel Liquid Alkanes: Kinetic Study

Fe-promoted Ni catalyst with extremely high loading and oxygen vacancy for lipid deoxygenation into green diesel

The catalytic performance of Ni catalyst in lipid deoxygenation into green diesel is commonly limited by the quantity of accessible active sites, the specific surface area, and the acidity of the catalyst. To cope with these problems, the Fe-promoted Ni catalyst on ZrO2 with 60 wt% Ni loading (60%Ni–Fe/ZrO2) is synthesized by the co-precipitation method. The deoxygenation of oleic acid over 60%Ni–Fe/ZrO2 catalyst attained 98.7% conversion and 91.8% alkane yield, much higher than that of 20%Ni–Fe/ZrO2-2 prepared with the impregnation method (42.8% conversion and 16.2% alkane yield). The kinetics of octadecanol hydrotreatment revealed that the activation energy over 60%Ni–Fe/ZrO2 was much lower than Ni–Fe/ZrO2-2 (78.48 kJ/mol vs.191.90 kJ/mol). From the catalyst characterizations, the excellent performance of 60%Ni–Fe/ZrO2 was ascribed to its fine Ni particles, abundant Ni sites, high surface area, and coordinated acidity. Moreover, the mechanism of lipid deoxygenation over 60%Ni–Fe/ZrO2 was proposed.

Mesoporous low silica X (MLSX) zeolite: Mesoporosity in loewenstein limit?

Synthesis of Low Silica X zeolite (LSX) with hierarchical porosity was achieved. The low silicon/aluminum ratio of this zeolite allowed to increase the number of active sites, as cationic positions (>25%) respect to the previous mesoporous X zeolite. Mesoporosity was induced by using sodium dodecylbenzene sulfonate (SDBS) during the synthesis. A dissolution time of 24 h for SDBS improved the zeolite crystallinity, maintaining the FAU characteristic framework, with a silicon/aluminum molar ratio near the unity (<1.1), limit of the Lowenstein’ rule. The surfactant removal at 773 K promoted the development of a wider pore size distribution. The heating rate highly determined the pore size distribution, resulting in a bimodal distribution (maxima at 80 Å and 290 Å) at low heating rate (1.3 K/min) and a unimodal distribution, with a maximum at 230 Å, at higher heating rate (8 K/min). The analysis by Transmission Electronic Microscopy (TEM) showed the mesoporous cavities in the zeolite nanoparticles. These cavities were generated by the SDBS spherical micelles removal. Mesoporous Low Silica X zeolite (MLSX) showed higher catalytic activity than the same zeolite without mesoporosity in the deoxygenation of oleic acid. The conversion reached a constant value around 100% with higher yield toward C 9 –C 18 hydrocarbons, representative fraction of sustainable aviation fuel (SAF). Therefore, this new mesoporous low silica X zeolite (MLSX) has a significant potential use as catalyst in the processing of bulky molecules. • Synthesis of Low Silica X zeolite (LSX) with hierarchical porosity was achieved. • The removal of the surfactant leaded to a wider pore size distribution. • Disordered mesoporous structure was arose by the removal of SDBS spherical micelles. • A good balance between crystallinity and mesoporosity can be achieve by calcination. • Mesoporous Low Silica X zeolite showed a higher resistance to deactivation.

Production of Second-Generation Diesel: Effects of Catalyst Passivation on the Deoxygenation of Oleic Acid

Production of Second-Generation Diesel: Effects of Catalyst Passivation on the Deoxygenation of Oleic Acid

Promoting hydrocarbon production from fatty acid pyrolysis using transition metal or phosphorus modified Al-MCM-41 catalyst

Oleaginous biomass conversion to liquid hydrocarbon biofuels has emerged as an effective solution to the energy crisis and environmental problems. In this process, the removal of oxygenated compounds will directly affect the effectiveness of subsequent biofuel applications. Herein, deoxygenation of oleic acid by catalytic cracking was conducted using five various elements (La, Ni, P, Zr and Ce) modified Al-MCM-41. The related characterizations were carried out for these catalysts, including N2 physisorption, XRD, XPS, pyridine-FTIR and NH3-TPD techniques. The results showed the mesoporous structure of Al-MCM-41 was maintained after different modifications, and these catalysts greatly improved the hydrocarbons content and physiochemical properties of biofuels. The modified catalysts tended to facilitate the decarbonylation pathway and showed high selectivity to alkane and aromatic hydrocarbons. Besides, La/Al-MCM-41 presented excellent anti-coking activity. Ni/Al-MCM-41 showed both high dehydrogenation and deoxygenation activities. The Zr modification and Ce modification had a promotion effect in the deoxidizing activity of the catalyst, owing to the formation of oxophilic metal oxides. Noteworthily, P/Al-MCM-41 displayed the best deoxidizing performance due to its high Brönsted acidity, which caused the highest hydrocarbons content (82.30 %) and the lowest fatty acids content (around 0 %) of the biofuel. Moreover, the resulting biofuel had not only low oxygen content (3.88 wt.%) and acid value (5.47 mgKOH g−1) but also a high calorific value (44.50 MJ kg−1), which could be processed into green diesel. Hence, the catalytic cracking of fatty acid over P/Al-MCM-41 has excellent potential to produce high-quality renewable fuels.

A novel kinetic model applied to heterogeneous fatty acid deoxygenation

An improved kinetic model for the deoxygenation of fatty acids was developed and compared with previously developed models. The models were compared using data collected from the deoxygenation of oleic acid using a novel, extensively characterized aerogel-based catalyst and previously published data of the deoxygenation of stearic acid, resulting in an extensive analysis ranging from 275 °C to 400 °C. The novel model was able to predict the behavior of reactants, intermediates and products for all cases analyzed in this paper. Akaike and Bayesian information criterions were applied, concluding that the novel kinetic model was indeed the best model to predict the behavior of both our original data and a previously published dataset. Relevant data regarding reaction rates and selectivity for the novel catalyst was given, showing a clear practical use of the results presented in this paper for the design and optimization of deoxygenation reactors.

Catalytic activity of trimetallic sulfided Re-Ni-Mo/γ-Al2O3 toward deoxygenation of palm feedstocks

Catalytic activities of trimetallic ReNiMo sulfide supported on γ-Al2O3 toward the deoxygenation of oleic acid, palm fatty acid distillate (PFAD), refined palm stearin (RPS) and refined palm olein (RPO) were studied. Relevant monometallic and bimetallic (i.e. Mo-, W-, Re-, ReMo-, ReW-, NiMo-) sulfides were also tested for comparison. Experiments revealed that, among all catalysts, ReNiMo sulfide catalyst exhibited the highest diesel yield of 76.5% from oleic acid, 72.5% from PFAD, 69.7% from RPS and 69.5% from RPO. Furthermore, the catalyst could maintain constant diesel yield level for at least six consecutive runs, whereas significant deactivation was observed from other catalysts due to high carbon deposition. Importantly, glycerol was also successfully employed as a hydrogen donor for deoxygenation reaction over this catalyst. From the catalyst characterizations, additional of Re increased the NiMo surface area by 20.4%, furthermore, it reduced the metal particle size and promote the metal dispersion on the support.

Synthesis and characterization of Pt-, Pd-, and Ru-promoted Ni–Ce0.6Zr0.4O2 catalysts for efficient biodiesel production by deoxygenation of oleic acid

Herein, we prepared Pt-, Pd-, and Ru-promoted Ni–Ce0.6Zr0.4O2 catalysts with improved oleic acid deoxygenation performance and investigated their physicochemical properties by N2 adsorption-desorption, X-ray diffraction (XRD), NH3 temperature-programmed desorption (NH3-TPD), and X-ray photoelectron spectroscopy (XPS). Among the above catalysts, the highest oleic acid conversion, C9–C17 selectivity, and oxygen removal efficiency were observed for Pt/Ni–Ce0.6Zr0.4O2, which was mainly ascribed to its highest surface defect oxygen fraction and acidity.

Efficient and stable Cu-Ni/ZrO2 catalysts for in situ hydrogenation and deoxygenation of oleic acid into heptadecane using methanol as a hydrogen donor

In this work, a series of ZrO2-supported Cu, Ni and bimetallic Cu-Ni catalysts were synthesized and evaluated for their activity and stability in the in situ hydrogenation and decarboxylation of oleic acid using methanol as a hydrogen donor. High-angle annular dark-field scanning transmission electron microscopy (HADDF-STEM), energy dispersive X-ray spectroscopy (EDS-mapping), X-ray diffraction (XRD) and temperature programmed reduction (TPR) characterizations revealed that the as-synthesized Cu-Ni/ZrO2 was a Cu-Ni alloy that was highly dispersed on mixed m-ZrO2 and t-ZrO2. The bimetallic Cu-Ni/ZrO2 nanostructures not only exhibited better catalytic activity for the conversion of oleic acid compared to monometallic Cu/ZrO2 and Ni/ZrO2 catalysts but also demonstrated good reuse performance. The formation of the Cu-Ni alloy facilitated the decarboxylation reaction and inhibited the cracking reaction, leading to enhanced catalytic performance. The good stability of Cu-Ni/ZrO2 was primarily due to the good hydrothermal stability of the ZrO2 support.

Deoxygenation of oleic acid under an inert atmosphere using molybdenum oxide-based catalysts

In this study, the deoxygenation of oleic acid under a N2 atmosphere over metal oxide catalysts is investigated for the production of green diesel hydrocarbons. The molybdenum oxide catalysts with promoters (Ni, Co, and Cu) and varying catalyst loadings (19–34 wt%) on γ-Al2O3 support are prepared by an incipient wetness impregnation method and characterized by XRD, FE-SEM/EDX, TEM, XPS, and N2 sorption. The catalytic testing is carried out in a batch reactor with various reaction times (3–9 h) and temperatures (300–350 °C) under N2 pressure (10 and 40 bar). The NiMo oxide/γ-Al2O3 exhibits the highest performance with over 80% conversion and good selectivity toward C17 hydrocarbon products. The catalytic performance of the NiMo oxide/γ-Al2O3 remains stable during 4 reaction cycles. Decarboxylation (DCO2) and decarbonylation (DCO) are observed to be the reaction pathways of the deoxygenation and these reactions are enhanced by increasing reaction temperature and time. Stearic acid and other hydrogenated compounds were produced via the in situ hydrogenation which was proposed as a competitive reaction in the deoxygenation of oleic acid under the N2 pressure. The DFT calculations confirm that the dehydrogenation and hydrogenation reactions could occur on the MoO3 surface. These processes are responsible for the in situ formation of hydrogen species, leading to the formation of hydrogenated products. Hydroxyl groups on the terminal oxygen sites created by dehydrogenation could contribute to the surface vacancy and further promote the DCO2 or DCO pathway. The molybdenum oxide-based catalysts show a great potential for green diesel production without the use of H2 feed.

올레산의 탈산소 반응에서 Ni-Ce0.6Zr0.4O2 촉매의 Ni 담지량에 따른 영향

올레산의 탈산소 반응에서 Ni-Ce0.6Zr0.4O2 촉매의 Ni 담지량에 따른 영향

Promotional Effect of WOxin Pt-WOx/AlPO4-5 Catalyzed Deoxygenation of Fatty Acids

WOx promoted Pt/AlPO4-5 catalysts with varying Pt and W contents were prepared by wet-impregnation method and characterized. Catalysts with Pt to W weight ratio of 1:2 exhibited higher catalytic performance than the other compositions in deoxygenation of oleic acid (OA). WOx enhanced significantly the catalytic activity of Pt and enabled quantitative conversion of OA to linear alkanes (predominantly C18/C17) at a temperature as low as 280 °C. It changed the reaction pathway from decarbonylation/decarboxylation (DCO for Pt/AlPO4-5) to hydrodeoxygenation (HDO for Pt-WOx/AlPO4-5). It affected the particle size and redox behaviour of Pt. The enhanced H-spill over (by 14.8 %) and presence of strong acid sites (300 - 500 °C) are the cause for the high activity of Pt-WOx/AlPO4-5 catalysts even at lower temperatures. Partially reduced WOx activates OA and leads to the HDO product (C18). In the absence of WOx, Lewis acid sites of the support activate OA through the C=O group and Pt facilitates C−C cleavage and formation of DCO product (C17).

Deoxygenation of oleic acid: Influence of the synthesis route of Pd/mesoporous carbon nanocatalysts onto their activity and selectivity

Abstract Supported Pd nanocatalysts were prepared by deposition of Pd nanoparticles (NPs) onto spherical mesoporous carbon beads (MB) functionalized by thermal or acidic treatement. The Pd NPs were synthesized by decomposition of [Pd 2 (dba) 3 ] (dba: dibenzylideneacetone) under dihydrogen either directly on the carbon supports without stabilizer leading to naked Pd NPs (Pd/MB series) or in solution in the presence of a stabilizer (polymer (PVP series) or triphenylphosphine (TPP series)) to obtain stable colloidal solutions that were further used to impregnate the carbon materials to have carbon-deposited Pd NPs. The NPs deposited on carbon displayed a Pd loading from 0.5 to 14.8 wt.% and were characterized by different techniques (nitrogen physisorption at 77 K, H 2 -chemissorption and TPD, XRD, XPS and HRTEM). Their catalytic performance in deoxygenation of oleic acid was evaluated in batch and flow reaction conditions. Flow conditions led to superior results compared to batch. No aromatic compounds were detected as side products, but in the case of the Pd/MB series, octadecanol and octadecane were significantly formed suggesting the involvement of a deoxygenation mechanism in which the hydrocarbons were produced via both decarbonylation/decarboxylation and dehydration steps. Further experiments carried out in H 2 /N 2 mixture or in pure N 2 highlighted the key role of hydrogen. For a N 2 /H 2 of 2.5:1 the dehydration route was crossing out and even no traces of octadecanol nor octadecane were detected. Then, complete removal of H 2 produced heptadecene in a high excess compared to heptadecane (almost 7–1) thus suggesting the decarbonylation/decarboxylation steps as the main route. ICP-OES measurements indicated no leaching of palladium and simple washing of catalysts with mesitylene allowed recycling without any change in conversion or product distribution.

Deoxygenation of oleic acid over Ce(1–x)Zr(x)O2 catalysts in hydrogen environment

Ce(1–x)Zr(x)O2 catalysts were prepared by co-precipitation method for deoxygenation (DO) of oleic acid. The CeO2/ZrO2 ratio was systematically varied to optimize Ce(1–x)Zr(x)O2 catalysts. Ce0.6Zr0.4O2 exhibited the highest oleic acid conversion as well as high selectivity to C9 ∼ C17 compounds (diesel fuel range) at the reaction temperature of 300 °C. The high activity/selectivity of Ce0.6Zr0.4O2 catalyst was correlated to its reducibility, oxygen storage capacity and crystallite size.