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Unlike fossil fuels, biomass has oxygen amounts exceeding 10 wt%. Hydrodeoxygenation (HDO) is a crucial step in upgrading biomass to higher heating value liquid fuels. Oxygen removal has many challenges due to the complex chemistry and the high reactivity leading to irreversible catalyst deactivation. In this study, the focus is on the catalytic HDO of aromatic oxygen‐containing model compounds in biomass: phenols and cresols. In the current work, literature on catalytic HDO of phenols using molecular hydrogen is reviewed, with a focus on non‐nickel‐based mono‐ and bi‐metallic catalysts, as nickel‐based catalysts were reviewed elsewhere. In addition, the catalytic HDO of m‐cresol using molecular hydrogen is examined. This review also addresses the use of hydrogen donors for the HDO of phenols and cresols. The operating conditions, catalysts, products, and yields are summarized to find the catalyst with promising activity and high selectivity toward aromatics. A critical review of the reactions that successfully led to HDO is presented and research gaps related to the HDO of phenols and cresols are highlighted. The conclusions provide potential successful catalyst combinations that can be used for HDO of phenols, cresols, and liquid aromatic hydrocarbons. [ABSTRACT FROM AUTHOR]

In this paper, novel Ni2P/WO3-ZrO2 bifunctional catalysts are prepared by an isovolume impregnation method. A series of characterizations (e.g., Py-IR, TEM, and XPS) demonstrated that the introduction of WO3 resulted in the acidity of the carrier and the formation of a well-dispersed Ni2P crystalline phase. The hydrodeoxygenation and hydroisomerization properties were evaluated by single-factor experiments using stearic acid as a model compound. Under the same conditions (solvent-free and relatively mild), the product obtained with a low amount of catalyst (stearic acid:catalyst = 40:1 wt.%) has a high deoxygenation rate (> 96%). The addition of an acidic carrier also gave the catalyst excellent hydroisomerization properties, which were excellent for increasing the low-temperature fluidity of the biodiesel. In addition, the effects of catalyst dosage, H2 pressure, reaction temperature, and reaction time on the hydroisomerization of stearic acid were investigated using the response surface method. In the response surface experiments, the deoxygenation rate of all experimental products is above 98%. The increase in catalyst dosage, reaction temperature, and decrease in H2 pressure favored the increase in isoparaffin content, and the reaction time had the least effect. The isoparaffin content varied significantly in response surface experiments, with molar ratios in the product ranging from 3 to 30%. There are interactions between the independent variables and a high coefficient of determination of the regression model (R2 = 0.9729), indicating that the experimental results were in good agreement with the model predictions. [ABSTRACT FROM AUTHOR]

Green diesel derived from sustainable biomass is an alternative and potential energy source to petroleum fossil fuel replacement in response to reducing carbon footprint and achieving a circular economy, which has sparked public interest and concern in advancing renewable energy development. Catalytic deoxygenation (CDO) is a promising method because it can process a wide variety of feedstocks and produce a diverse range of fuels. The CDO of soybean oil (SO) was executed using a modified low-cost dolomite catalyst denoted as NiO-CD catalyst and its performance has been compared with commercial zeolite heterogeneous-based catalysts such as ZSM-5, HY-zeolite and FCC. The NiO-CD catalyst exhibited exceptional deoxygenation ability, attaining an 88.6 % removal efficiency of oxygenated compounds, markedly surpassing all commercially available zeolite catalysts. The highest degree of CDO of SO via decarboxylation/decarbonylation (deCOx) reaction was achieved due to improvement in particle size, mesoporous structure and the presence of the synergistic effect of modified bi-functional acid-base properties of NiO-CaO/MgO catalyst. To investigate the effect of NiO-CD catalyst loading ranging from 1 to 7 wt%, a One Factor At a Time (OFAT) optimisation study was performed. The current study found that an optimised NiO-CD catalyst loading of 5 wt% yielded the highest green diesel (50.5 wt%) with an 88.63 % hydrocarbon composition. The influence of catalyst loading on deoxygenation activity is significant in green diesel production using NiO-CD catalyst.

The concentration of residual O2 in oxy-fuel combustion flue gas needs to be reduced before CO2 transportation, utilization, or storage. An original application of the printed circuit heat exchanger (PCHE) for catalytic combustion with natural gas (catalytic deoxygenation) is described for reducing the residual O2 concentration. The PCHE design features multiple adiabatic packed beds with interstage cooling and fuel injection, allowing precise control over the reaction extent and temperature within each reaction stage through the manipulation of fuel and utility flow rates. This work describes the design of a PCHE for methane–oxygen catalytic combustion where the catalyst loading is minimized while reducing the O2 concentration from 3 vol% to 100 ppmv, considering a maximum adiabatic temperature rise of 50 °C per stage. Each PCHE design differs by the number of reaction stages and its individual bed lengths. As part of the design process, a one-dimensional transient reduced-order reactor model (1D ROM) was developed and compared to temperature and species concentration axial profiles from 3D CFD simulations. The final design consists of five reaction stages and four heat exchanger sections, providing a PCHE length of 1.09 m at a processing rate of 12.3 kg/s flue gas per m3 PCHE. [ABSTRACT FROM AUTHOR]

The concentration of residual O2 in oxy-fuel combustion flue gas needs to be reduced before CO2 transportation, utilization, or storage. An original application of the printed circuit heat exchanger (PCHE) for catalytic combustion with natural gas (catalytic deoxygenation) is described for reducing the residual O2 concentration. The PCHE design features multiple adiabatic packed beds with interstage cooling and fuel injection, allowing precise control over the reaction extent and temperature within each reaction stage through the manipulation of fuel and utility flow rates. This work describes the design of a PCHE for methane–oxygen catalytic combustion where the catalyst loading is minimized while reducing the O2 concentration from 3 vol% to 100 ppmv, considering a maximum adiabatic temperature rise of 50 °C per stage. Each PCHE design differs by the number of reaction stages and its individual bed lengths. As part of the design process, a one-dimensional transient reduced-order reactor model (1D ROM) was developed and compared to temperature and species concentration axial profiles from 3D CFD simulations. The final design consists of five reaction stages and four heat exchanger sections, providing a PCHE length of 1.09 m at a processing rate of 12.3 kg/s flue gas per m3 PCHE.

WO3-ZrO2 solid acid catalysts were prepared by the impregnation method and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), Brunauer-Emmett-Teller (BET), and pyridine adsorbed IR spectroscopy (Py-IR). The catalysts were used for catalytic deoxygenation of Jatropha curcas oil. The optimal conditions for the deoxygenation of the generated oil were obtained by response surface methodology based on Box-Behnken four-factor experiments. Response surface methodology (RSM) was applied while determining the optimal conditions for the Jatropha oil deoxygenation percentage. The rate was calculated based on Box-Behnken four-factor experiments, with reaction temperature, catalyst amount, reaction time, and reaction pressure as independent variables and the deoxygenation of Jatropha curcas oil as response values. The optimal reaction conditions obtained were a temperature of 370 °C, pressure of 2 MPa, time of 7 h, and catalyst amount of 0.22 g. The deoxygenation percentage of the generated oil under the optimal conditions was 95.1%, which was close to the theoretical value, indicating that the model was reliable. The generated oil contained more jet fuel components, with 68.1% C8-C16, 12.0% isoalkanes, 14.2% cycloalkanes, and 8.9% aromatic compounds under the optimum conditions. This study provides an effective and simple method for preparation of bio-aviation fuel.

This work investigates the optimization of reaction parameters with the Taguchi method for catalytic deoxygenation of waste cooking oil (WCO) as an alternative renewable fuel process. Commercial sulphated-ferric (II) oxide/alumina oxide catalyst has the potential as a deoxygenation catalyst due to its good physicochemical properties which enhance the removal of oxygenated species. The obtained pyrolysis oil analysed by GC-MS revealed the selectivity of the pyrolysis oil mostly in the range of light diesel and kerosene fraction. From an analysis of variance (ANOVA), temperature awarded the most significant impact (86.62%) in this catalytic deoxygenation as compared to three other parameters followed by reaction time > N2 flow > catalyst loading. From the GC-MS analysis, the maximum renewable diesel fraction of 49.66% was obtained at 400 °C, 1 wt% of catalyst, 90 min of reaction time and 20 cm3/min N2 flow. The predicted model by Taguchi in the present study validated by the experimental work shows a promising application in optimising the catalytic pyrolysis process for future use.

• CuO-NiO/Al 2 O 3 catalyst with palm oil used to synthesize green fuel. • GasTurb-13 data is validated engine performance model using green fuel. • GD10PME10 blend had the lowest TSFC, matching Jet-A1 efficiency at high speeds. • GD20OME30 has the lowest emissions (CO, and CO 2) and temperature. • NO x rose with blends; GD10PME10 closest to Jet-A1. Optimized blends can cut NO x. This study aims to assess the impact of using green fuel in place of biodiesel on the performance and exhaust emissions of air-breathing engines. GasTurb 13 is utilized to forecast the engine's performance (kingTech 180 k turbojet engine). Catalytic deoxygenation of vegetable oils produces green diesel, offering an alternative to biodiesel. Physiochemical properties of GD blends (PME30GD20, PME20GD30, PME10GD10) were analyzed, and GasTurb-13 software predicted engine performance and emissions, validated with experimental data. The results show that GD10PME10 exhibited higher density (767.6 g/m3) than pure green fuel, while viscosity dropped by 53.85 % compared to PME. GD outperformed Jet-A1 by 0.74 % in heating value, with GD10PME10 having the highest at 42.63 MJ/kg. Engine performance measures included thrust, mass fuel flow, thrust-specific fuel consumption, and exhaust gas temperature. GD10PME10 showed a 12.5 % thrust increase and the lowest TSFC (95 g/kN.s) at 80,000 RPM compared to Jet-A1. GD20PME30 achieved the lowest EGT (550 °C) at the same RPM. Regarding emissions, GD20PME30 emitted the lowest CO (100,000 RPM, 150 ppm) and 0.5 % less CO 2 (90,000 RPM) than Jet-A1. GD10PME10 produced the lowest NOx (12.5 ppm) at maximum speed, while Jet-A1 emitted the least NOx (7.5 ppm) at 120 k RPM. Overall, the data suggested that green fuel might increase the physiochemical properties of biodiesel blends, hence improving the fuel's capacity to burn more effectively in aero-engines. [ABSTRACT FROM AUTHOR]

In line with global demand for greenhouse gas reduction, the aviation industry has invested in biofuels development. A source feedstock that deserves special mention for this process is microalgae, because of its cultivation of renewable biomass with high yields, low cost, and high CO2 sequestering potential. This research aimed the study of microalgae culture with hard potential for biofuel production and its obtaining through catalytic deoxygenation to renewable source hydrocarbons in C12–C18 range. Thus, the oils of the Scenedesmus acuminatus and Cosmarium sp. species were cultivated and identified. Scenedesmus acuminatus oil is the majority composition of palmitic acid (C16:0) and has a higher production and yield than Cosmarium sp. oil. Scenedesmus acuminatus oil was then submitted to catalytic deoxygenation by the semi-batch reaction using the 5% Pd/C catalyst. The obtained results showed a selectivity of 82.9% and n-alkane yielding of 36.6%, placing the specie as potential biojet fuel precursor. [ABSTRACT FROM AUTHOR]

A low-rank coal was subjected to deoxygenation using NiO/Mo2O3-ZSM-5 as the catalyst and ethanol as the solvent under pressurized hydrogen circumstance to acquire a catalytic product (CP). Another parallel reaction was repeated with the same procedure but with nitrogen circumstance and without the catalyst to obtain a non-catalytic product (NCP). Both CP and NCP were analyzed with a Fourier-transform infrared spectroscopy, a gas chromatography/mass spectrometer (GC/MS) and an Orbitrap mass spectrometer (Orbitrap MS) to understand the deoxygenation features of low-rank coal. Low polar and molecular mass compounds were detected in NCP and CP using GC/MS. Compared with GC/MS, more species and high polarity were identified in NCP and CP by Orbitrap MS. The three analytical techniques indicated the effective oxygen removal during the catalytic treatment and provide a comprehensive evaluation of the deoxygenation process. [ABSTRACT FROM AUTHOR]

• Fe doped CeO 2 was prepared by coprecipitation method as ketonization catalysts. • 33%Fe-CeO x showed the best performance in the conversion of xylan to ketones. • The production of acetone and 2-butanone showed relative competitiveness. • Fe doping favored the production of ethylene glycol and thus promoted the yield of acetone. Ketonization of oxygenated compounds in pyrolytic products of biomass is an effective means for deoxygenation and upgrading of bio-oils. However, the ketonization potential of biomass-derived sugars and the mechanism underneath remain unclear. On this basis, a series of Fe doped CeO 2 catalysts were synthesized and employed for catalytic ketonization of xylan. Characterization of the catalysts proved the successful formation of the Fe-CeO x solid solution. Doping an appropriate amount of Fe (20–33%) ions on CeO 2 could obviously increase the number of oxygen vacancy and basic sites by up to 56.31% and 29.6%, respectively. During the catalytic reaction of xylan, pure CeO 2 exhibited a good ketonization ability during xylan pyrolysis, and the introduction of a certain amount of Fe further enhanced the ability. The highest yield of ketones was obtained by 33%Fe-CeO 2 , which was 38% higher than pure CeO 2. The selectivity to linear ketones (acetone and 2-butanone) reached a maximum of 85% for 57%Fe-CeO x. Thus, oxygen-rich compounds had been converted to low oxygen containing and high-quality ketone components. Introducing Fe into CeO 2 favored the production of ethylene glycol rather than 2,3-dihydroxy propanal, and thus promoted the yield of acetone. This investigation provides fundamentals for the deoxygenation of biomass through catalytic ketonization, aiming at the production of value-added ketone products. [ABSTRACT FROM AUTHOR]

Catalytic deoxygenation of coal is an important step to obtain high quality coal-derived liquid fuels. Bimetallic catalysts exhibit excellent hydrodeoxygenation performance, because their synergistic effects. In this work, NiO–Mo 2 O 3 /ZSM-5 was prepared by impregnation method, and applicated to catalytic hydrodeoxygenation of Wucaiwan long flame coal (WCW). The thermal dissolution (TD) and catalytic hydrodeoxygenation (HDO) of WCW were investigated using cyclohexane as the solvent. The soluble portions from TD (SF NHDO) and HDO (SF HDO) were analyzed by gas chromatograph/mass spectrometry. The relative abundance of arenes and alkanes in SF HDO increased by 12.30 % and 29.98 %, respectively, compared to that in SF NHDO. Most detected oxygen-containing compounds in SF NHDO were alcohols and ethers, and their relative abundances decreased by 50.27 % and 84.13 %, respectively, after the catalytic treatment. Thus, the cleavage of C–O bond and deoxygenation in WCW were significantly proceeded during the HDO of coal over NiO–Mo 2 O 3 /ZSM-5 catalyst. The hydrodeoxygenation mechanism was proposed according to the catalytic deoxygenation of model compounds. Mobile H+ attacks oxygen atom and iso-carbon in coal, and produces aryl-molecules and aromatic alcohols. Aryl-molecules can be also generated from the attacking of H+ to the oxygen atom in aromatic alcohols. • NiO–Mo 2 O 3 /ZSM-5 was prepared for hydrodeoxygenation of long flame coal. • The catalyst is effective for the generation of arenes and alkanes. • Hydrodeoxygenation mechanism was revealed via catalytic reaction of model compounds. [ABSTRACT FROM AUTHOR]

The present work is focused on the development of an effective process for the conversion of waste soap into fuel oil and gas. The waste soap was converted into highly combustible gas and oil by using low-cost white cement and burnt brick powder catalysts. Optimum conditions for both catalytic and non-catalytic pyrolysis were investigated by varying temperature, weight of catalyst, and reaction duration. All the experiments were carried out in a custom-made furnace and stainless steel pyrolyzer. The gaseous product was identified as alkenes and alkynes during their chemical analysis. The presence of carbon monoxide in the gaseous product was assessed from the color of the flame while the presence of hydrogen was examined through the GC-MS analysis. The oil fraction was separated into gasoline and kerosene fractions using fractional distillation approach. The qualitative and quantitative analysis of the oil was carried out using gas chromatography coupled with mass spectrometer (GC-MS). The oil obtained at 600 °C by non-catalytic pyrolysis, white cement–catalyzed, and clinker–catalyzed pyrolysis presented hydrocarbon content of 13.27%, 70.70%, and 46.44%, respectively. [ABSTRACT FROM AUTHOR]

It has been found that catalytic deoxygenation of triglycerides is a viable pathway for obtaining renewable liquid fuels to contribute to meet the global energy demand. In this study, SBA-15 mesoporous silica was synthesized in a pure form and modified with mesitylene (TMB) as a swelling molecule (SBA15-TMB). Catalysts with 0.5, 1.5 and 3.0 wt% Pd were synthesized and tested by deoxygenation of stearic acid (SA), obtaining initial conversions of 68–98% that decreased to 36–73% after 6 h time-on-stream. The most abundant product was n-heptadecane, with a selectivity of ~ 90%. The most active catalyst evaluated with SA was 3.0 wt% Pd over unmodified SBA-15 (30Pd/SBA-15). Subsequently, fresh and regenerated 30Pd/SBA-15 catalysts were tested with waste cooking oil (WCO) feed, obtaining conversions of 74 and 72%, respectively, but the fresh catalyst allowed a better oxygen removal (91%. Additionally, commercial Pd(10wt %)/C catalyst was evaluated, obtaining results comparable to those for the regenerated 30Pd/SBA-15 catalyst. The main WCO reaction product for all catalysts was a diesel fraction (C12-C21), and the quality of the products was not very different, following the order: Pd(10wt %)/C > 3.0Pd/SBA-15-regenerated > 3.0Pd/SBA-15-fresh. The results obtained indicate that shynthetized catalysts of this study are promising for obtaining renewable diesel from low-cost feeds while using low hydrogen consumption. [ABSTRACT FROM AUTHOR]

This work reported a new strategy in producing synthetic diesel hydrocarbons from a mono-unsaturated fatty acid model compound, oleic acid and replacing high pressure molecular hydrogen with a hydrogen-rich donor solvent, 1,2,3,4–tetrahydronaphthalene for the first time. Under the absence of an external H 2 supply, oleic acid was dispersed in 1,2,3,4-tetrahydronaphthalene and hydrotreated over commercially available 5 wt% Pd/C in a fed-batch reactor to obtain diesel range fuel products. A maximum oleic acid conversion of 92.4% and highest diesel hydrocarbon selectivity of 67.4% were achieved at 330 °C with a solvent to fatty acid mass ratio of 1 for 3 h under autogenous pressure. In-situ H 2 produced from 1,2,3,4-tetrahydronaphthalene operated as an effective hydrogen donor vehicle that continuously transported active hydrogen species from gas phase to reactant acid molecules and radical fragments. It minimized polymerization of reaction intermediate and suppressed coke formation, which subsequently improved catalyst resistance toward deactivation. Image 1 • Decarboxylation of oleic acid to alkanes over Pd/C in 1,2,3,4-tetrahydronaphthalene. • Addition of 1,2,3,4-tetrahydronaphthalene as donor solvent and H 2 source. • Tandem release of in situ H 2 from 1,2,3,4- tetrahydronaphthalene solvent. • Up to 67.4 w.t% of diesel-like hydrocarbon selectivity was achieved after 3 h. • Improve catalyst resistance toward deactivation and prolong catalyst lifetime. [ABSTRACT FROM AUTHOR]

The present experimental investigation aims at production of second-generation biofuels from straight vegetable oils (SVOs) and carrying out their performance assessment in a compression ignition (CI) engine. The intended second-generation biofuels, i.e., deoxygenated vegetable oils (DVOs), were produced through catalytic deoxygenation of palm and karanja SVOs over 5 wt% Pd/C catalyst under an inert (N2) atmosphere using a batch autoclave reactor. Fuel characterization and elemental analysis were carried out for the produced DVOs to evaluate various fuel properties. In order to evaluate the fuel composition and presence of diesel range aliphatic hydrocarbons, GC-MS and FT-NMR tests were carried out. The engine performance and emission characteristics with the DVOs were evaluated in a developed experimental diesel engine setup. Results showed that the DVOs exhibit better engine performance, lower emissions, and marginally higher NOx emissions compared to those with diesel fuel. In order to establish the DVOs as possible CI engine fuels, the performance and emission characteristics with the DVOs were compared against those with their corresponding established B20 biodiesel blends. The comparative assessment revealed that the engine performance and emission characteristics with the DVOs are superior compared to those with the corresponding B20 biodiesel blends. Especially, the NOx emissions with the DVOs are significantly lower as compared to their corresponding B20 biodiesel blends. [ABSTRACT FROM AUTHOR]

Catalytic deoxygenation of coal enhances the stability and combustion performance of coal-derived liquid fuels. However, determination of the selectivity of removal of oxygen atoms incorporated in or residing outside of aromatic rings is challenging. This limits the ability to evaluate the success of catalytic deoxygenation processes. A mass spectrometric method, in-source collision-activated dissociation (ISCAD), combined with high resolution product ion detection, is demonstrated to allow the determination of whether the oxygen atoms are in aromatic compounds reside outside of aromatic rings or part of the aromatic system, because alkyl chains can be removed from aromatic cores via ISCAD. Application of this method for the analysis of a subbituminous coal treated using a supported catalyst revealed that the catalytic treatment reduced the number of oxygen-containing heteroaromatic rings but not the number of oxygen atoms residing outside the aromatic rings. [ABSTRACT FROM AUTHOR]

Bio-jet fuel range alkanes were prepared by catalytic deoxygenation reaction of non-edible acid oils with no added hydrogen. A WOx[6]/Pt[1.6]/TiO 2 was used for the deoxygenation of stearic acid and Jatropha fatty acid derived from Jatropha oil by hydrolysis. Tungsten addition to the Pt/TiO 2 showed remarkably enhanced performance, a degree of deoxygenation of 86%, which is more than two times higher than that of the Pt/TiO 2 , even though the WOx/TiO 2 had almost no activity for deoxygenation reaction. The enhanced Pt-related hydrogen uptake, measured by H 2 -TPR, and XPS analysis showed the intimate contact of tungsten with Pt nanoparticles supported on TiO 2 . This tight contact allows for easier C C cleavage over Pt nanoparticles and this is assisted by the strong bonding between tungsten and oxygen in the reactant, resulting in more C 17 hydrocarbon production on the WOx/Pt/TiO 2 . [ABSTRACT FROM AUTHOR]

An efficient and highly selective CaO-MgO-promoting γ-Al 2 O 3 decarboxylation catalyst was fabricated with different CaO to MgO ratios via a ball-milling method for regulating product distribution and production of gasoline-kerosene-diesel hydrocarbons via the catalytic copyrolysis of oleic acid (OA) and methanol under hydrogen-generating conditions. In addition, influencing factors, reaction mechanisms, possible reaction pathways and deactivation mechanisms were probed. The results showed that combining Ca, Mg and AlOx was vital for boosting oleic acid conversion, and synergy between metal and acid active sites via strong metal-support interactions enhanced deoxygenation-cracking activity. High-alkalinity CaO boosted C-C/C C bond cleavage, and MgO provided medium-strength Lewis acid sites; additionally, a large BET surface area and mesopore volume suppressed excessive hydrocracking reactions, improving biogasoline yield. Methanol addition provided active hydrogen atoms to enhance biogasoline selectivity at the expense of diesel and heavy oil production via olefinic cycles and aromatic cycle mechanisms and reduced coke deposition. The maximum hydrocarbon and biogasoline yields of 94.53% and 57.59% were achieved at OA/methanol= 5:1 and pyrolysis/catalytic temperature= 450/500 °C with1 g catalyst at a feedstock input rate of 0.1 ml/min. [Display omitted] • A novel porous CaO-MgO-Al 2 O 3 catalyst was prepared by one-pot ball-milling method. • MgO-addition restricted the C C bond cleavage and promoted the formation of hydrocarbons. • A 57.59% yield of bio-gasoline at full OA conversion was obtained over Ca-Mg-Al= 5–25-70 with methanol. • Presence of CaO and MgO leads to the formation of less graphitic carbon structures. [ABSTRACT FROM AUTHOR]

The non-catalytic and in-situ catalytic co-pyrolysis of Huadian oil shale (OS) and microalgal powder (MP) were performed using a modified aluminum retort. By comparing the product yields and compositions for non-catalytic and catalytic pyrolyses, the catalytic effect of several additives, including MgO, CaO, ZrO 2 , Al 2 O 3 , zeolite Y, and zeolite ZSM-5, was investigated. This study focused on the deoxygenation performance of the pyrolytic oil. The oil yield increased with increasing MP addition in non-catalytic co-pyrolysis trials. At the OS/MP blending ratio of 3/1, the oil yield was 12.42 wt %, and the oxygen content and H/C ratio of oil were 11.54 wt % and 1.571, respectively. Both CaO and Al 2 O 3 significantly decreased the oxygen content of the oil to <7 wt % with less oil loss (<1 wt %). CaO catalysis facilitated the dehydrogenation of free radicals to release H 2 , thereby increasing alkene formation and decreasing the H/C ratio of the oil to 1.441. Al 2 O 3 catalysis increased the H/C ratio to 1.656 and improved the oil quality. ZSM-5 preferentially catalyzed the reaction between n -alkenes and nitrogenates to yield nitriles, and the catalytic performance for deoxygenation was negligible. Hence, Al 2 O 3 was selected as the most suitable additive for the co-pyrolysis of OS and MP. • CaO and Al 2 O 3 decrease the oxygen content of the oil with less oil loss. • CaO facilitates the dehydrogenation of free radicals to release H 2. • Al 2 O 3 increases the H/C ratio of the oil and improved the oil quality. • ZSM-5 catalyzes the reaction between n-alkenes and nitrogenates to yield nitriles. [ABSTRACT FROM AUTHOR]

In-situ catalytic upgrading of bio-oils derived from the fast pyrolysis of cellulose, lignin or sunflower stalk over Mg-doped Al-MCM-41 was investigated in details. It is found that Mg species with doping amounts ranged between 0.25 and 10 wt.% was well dispersed on Al-MCM-41, and that doping Mg on Al-MCM-41 effectively adjusted the acidity and basicity of the catalysts, resulting in significant improvement of bio-oil quality. Mg/Al-MCM-41 exhibited high selective conversion of bio-oils derived from cellulose, lignin or sunflower stalk to high value-added aromatic hydrocarbons via catalytic cracking, deoxygenation and aromatization. In the upgraded bio-oil, the relative total hydrocarbon amount reached up to approximately ≥80%, which consisted of aromatic hydrocarbon approximately 76% and aliphatic hydrocarbon approximately 4% for all feedstocks. The selectivity to the monocyclic aromatic hydrocarbons (MAHs) such as benzene, toluene and xylenes (BTXs) increased while the coke formed on the catalyst decreased with the increase in Mg doping amount. 1 wt.% Mg/Al-MCM-41 resulted in the highest relative total hydrocarbon amount in the upgraded bio-oil at lower catalytic deoxygenation temperature, and showed stable reusability for at least 5 cycles. It is expected that Mg/Al-MCM-41 can be widely applied for bio-oil upgrading in a practical process. [ABSTRACT FROM AUTHOR]

Triglycerides represent a type of sustainable energy source and robust catalysts for triglycerides refining to biofuels are very challenging. Herein, we report supported ruthenium catalysts, optimized from group VIII metal catalysts, for the selective conversion of triglycerides to diesel-range alkanes under mild conditions. The catalyst supports and ruthenium loadings show significant impacts on the performance of ruthenium catalysts, and Ru/TiO 2 with ruthenium weight loading of 1.68% is optimized for the reaction. Typically, the platform compound stearic acid could be directly converted, or via 1-octadecanol as an intermediate product, to n -heptadecane and n -octadecane in n -heptane solvent using the optimized Ru/TiO 2 catalyst at 473 K and under 3 MPa H 2 . On the basis of catalytic and spectroscopic characterization results, large ruthenium metal particles are established as the preferred active sites for stearic acid conversion. The complete reaction network of stearic acid deoxygenation on flat Ru (0001) is investigated by theoretical calculations. It is revealed that different pathways run simultaneously during the reaction and the adsorbed acyl species C 17 H 35 CO* are the key reaction intermediates for the catalytic deoxygenation on Ru (0001). The removal of adsorbed CO by hydrogenation is the rate-controlling step contributing to the highest energy barrier within the reaction network. [ABSTRACT FROM AUTHOR]

Biomass-derived fast pyrolysis oil (bio-oil) is a potential alternative replacement for conventional transportation fuels. But negative properties such as lower energy density, higher water content and acidity prevent the direct use of pyrolysis oil as a fuel. Catalytic deoxygenation of pyrolysis oils to hydrocarbons has been studied widely with application of high heat and hydrogen pressure. However, consumption of a large amount of expensive hydrogen has remained a problem for this technology. Therefore, development of an efficient and reduced hydrogen deoxygenation method would be desirable. In this study, we have applied catalytic deoxygenation of pretreated bio-oil in the presence of pressurized syngas to produce liquid hydrocarbons. The pretreatment is an oxidation step that converts aldehydes to carboxylic acids that are more conducive to catalytic conversion to hydrocarbons than are raw bio-oils. The pretreated bio-oil allowed performance of a partial deoxygenation step with a low amount of hydrogen (syngas). This partially deoxygenated product was then fully deoxygenated with pure hydrogen to produce hydrocarbons. Properties of the resultant liquid hydrocarbons were analyzed by ASTM standards for transportation fuels. The hydrocarbon mixture obtained by our process was analyzed by Fourier transform infrared spectroscopy, detailed hydrocarbon analysis, nuclear magnetic resonance spectroscopy and simulated distillation. [ABSTRACT FROM AUTHOR]

Deoxygenation of stearic acid has been investigated over the supported Ni nanoparticles on the mesoporous activated carbon (MAC) under relatively mild conditions (260°C), where the MAC was obtained from Kraft lignin by H3PO4 activation. The precursor and catalyst have been characterized by X-ray diffraction (XRD), N2 adsorption-desorption measurements and transmission electron microscopy (TEM). The influence of the H2 pressure, Ni loading, reaction time, and initial concentration of stearic acid on the composition and yield of hydrocarbons has also been checked. A high C17 to C18 hydrocarbons yield of 81.3%, a C17 hydrocarbon selectivity of 94%, and a conversion of 100% were obtained at 260°C, 6 bar H2 pressure, and stearic acid concentration of 0.15 mol/L after 10 h of reaction time over the 25 wt % Ni/MAC catalyst. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 607-612, 2015 [ABSTRACT FROM AUTHOR]

The environmental impact from the use of fossil fuel cum depletion of the known fossil oil reserves has led to increasing interest in liquid biofuels made from renewable biomass. This study presents the first experimental report on the catalytic pyrolysis of Napier grass, an underutilized biomass source, using ZSM-5, 0.3HZSM-5 and zinc exchanged zeolite-A catalyst. Pyrolysis was conducted in fixed bed reactor at 600 °C, 30 °C/min and 7 L/min nitrogen flow rate. The effect of catalyst-biomass ratio was evaluated with respect to pyrolysis oil yield and composition. Increasing the catalyst loading from 0.5 to 1.0 wt % showed no significant decrease in the bio-oil yield, particularly, the organic phase and thereafter decreased at catalyst loadings of 2.0 and 3.0 wt %. Standard analytical methods were used to establish the composition of the pyrolysis oil, which was made up of various aliphatic hydrocarbons, aromatics and other valuable chemicals and varied greatly with the surface acidity and pore characteristics of the individual catalysts. This study has demonstrated that pyrolysis oil with high fuel quality and value added chemicals can be produced from pyrolysis of Napier grass over acidic zeolite based catalysts.

Highlights: [•] Natural triglycerides converted to hydrocarbons by catalytic deoxygenation. [•] GC×GC-TOFMS used to quantify hydrocarbons and oxygenated intermediates. [•] Generalized reaction pathways of metal and Mo-based sulfide catalysts are proposed. [•] Metal catalysts showed higher activity on C C bond scission. [•] Mo-based catalysts showed higher activity on C O bond scission. [ABSTRACT FROM AUTHOR]

To address issues related to climate crises, microalgae-based biofuels are considered a promising option for reducing carbon dioxide emissions in the transportation sector. However, despite extensive research conducted over the past 20 years, there are major limitations in the application of conventional algal biodiesel, such as the instability of oxygen-containing fuel, blending wall limitations (less than 20%), and poor cost competitiveness. Recently, biomass-based renewable hydrocarbon fuels (drop-in biofuels) have been considered technologically competitive alternatives to petrofuels owing to the advantages of carbon dioxide reduction, high energy density, and compatibility with existing infrastructure. This review discusses the integrative utilization of whole algal biomass for the development of an advanced algal biorefinery process that could strategically help produce drop-in biofuels and multiple by-products to meet the growing fuel demand and secure economic feasibility. This review provides an updated overview of recent technical advancements in the (1) mass cultivation of oleaginous algal biomass obtained from industrial wastes, (2) production of renewable biodiesel and bio-jet fuel using algal lipids via catalytic upgrading, and (3) diversification of bio-products generated from residual lipid-extracted biomass, such as hydrogen, methane, alcohols, bio-oils, organic acids, biosorbents, biomaterials, and nutrients. The challenges and prospects for practical application are discussed along with the major constraints on the commercialization of integrative algal biorefining. [Display omitted] • Integrative utilization of whole biomass is required for economic algal biorefining. • Mass cultivation of lipid-rich algal biomass using CO 2 -rich flue gas and wastewater. • Catalytic upgrading of renewable diesel and bio-jet fuel from algal neutral lipids. • Diversification of products from lipid-extracted biomass via subsequent conversions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Recent advances in catalytic deoxygenation (CDO) of plant oils and fatty acids are presented. • Notable shift in CDO works from edible to non-edible oils as feedstock. • Catalysis, process, and kinetics of CDO are discussed in detailed. • CDO process with in situ self-sustaining H 2 system is gaining much interests. • Technical challenges and future prospects of CDO process are proposed. With the inevitable human innate aspirations for better urban mobility and sustainable economic development, bio-based transportation fuels are projected to play an essential role in the foreseeable automotive transportation sector. Agricultural-based renewable diesel (RD) is the prospective fuel of tomorrow due to its excellent fuel properties and environmentally friendly attributes. This review summarises the evolution of research works related to upgrading of plant oils and fatty acids to diesel-like hydrocarbons via catalytic deoxygenation (CDO) technologies in the past decade. Throughout this review paper, a strong emphasis is put on the fundamental chemistry, reaction mechanism, and kinetic modelling. The influence of the key process parameters that may affect the diesel hydrocarbon product yields/selectivity including the types of feedstock, types of catalyst, and key operating conditions are also explicated. This paper also addresses the technical barriers, challenges, and prospects of CDO technologies that could potentially bridge between the existing research gaps and industrial practices in these areas. In summary, this paper will help scientific researchers and industrial practitioners to explore the recent scientific advances and potential strategies in producing sustainable diesel fuel from natural plant oils and fatty acids. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hydrotreatment of oil in batch and continuous reactors, to produce green diesel. [•] Finding the optimum operating conditions for using the Ni and CoMoS x catalysts. [•] Comparisons of reaction and product, between batch and continuous systems. [•] The Ni catalyst showed higher activity in decarboxylation/decarbonylation. [•] The CoMoS x catalyst showed higher activity in hydrodeoxygenation. [Copyright &y& Elsevier]

Deoxygenation was systematically investigated using either stearic, oleic or linoleic acids as a feedstock at 300 °C under 1 vol% hydrogen in argon over a mesoporous Pd/C (Sibunit) catalyst producing one less carbon containing, diesel-like hydrocarbons. The results revealed that catalyst activity and selectivity increased with less unsaturated feedstock. The main products in the case of stearic acid were desired C17 hydrocarbons, whereas the amounts of C17 aromatic compounds increased in case of oleic and linoleic acids. Catalyst deactivation was relatively prominent in linoleic acid deoxygenation giving only 3% conversion of fatty acids in 330 min. The deactivation originated from the formation of C17 aromatic compounds and fatty acid dimers, which was confirmed by size exclusion chromatographic analysis. The latter compounds were formed via Diels-Alder reaction. [ABSTRACT FROM AUTHOR]

Catalytic deoxygenation of tall oil fatty acids (TOFA) was demonstrated over palladium catalysts supported on mesoporous carbon at 300 °C using dodecane as a solvent. Maximally 95% selectivity to linear C17 hydrocarbons was achieved. The effects of reaction atmosphere and initial TOFA concentration were investigated. [ABSTRACT FROM AUTHOR]

There is growing interest about the conversion of lipids to renewable fuels as the alternatives of traditional petroleum. However, the development of efficient catalysts from readily available materials is still challenging. In this study, we demonstrated that the generation of diesel-like fuel from methyl palmitate (MP) through catalytic deoxygenation could be significantly promoted by modifying the ZrO 2 support with B 2 O 3 , a cheap and readily available non-metal oxide. Characterization results showed that the attaching boron atom to the framework of ZrO 2 support to form the B-O-Zr interconnection significantly increased the acidic site concentration. The enhanced acidity of B 2 O 3 /ZrO 2 catalysts afforded the improved efficiency for MP deoxygenation, and the maximum activity was obtained at a B/Zr molar ratio of 1/5 with the MP conversion of 86.6% and liquid yield of 69.3%. The effect of reaction temperature and H 2 pressure on the MP deoxygenation performance of B 2 O 3 /ZrO 2 catalysts were also evaluated systematically. Combining the catalytic and spectroscopic data, it revealed that the MP was firstly adsorbed at the oxygen vacancies of m -ZrO 2 and then converted to < C 15 , C 15 alkane and alkenes through decarbonylation, hydrocracking and dehydrogenation reactions. Efficient generation of diesel-like fuel can be obtained over B 2 O 3 -modified ZrO 2 catalysts. [Display omitted] • Diesel-like fuel was produced from Methyl Palmitate by B 2 O 3 -modified ZrO 2. • 86.6% conversion of MP and 69.3% liquid products were obtained. • The strong acidic site was originated from the B-O-Zr interconnection. • The performance of B 2 O 3 (1)/ZrO 2 (5) was nearly twice as much as that from pure ZrO 2. [ABSTRACT FROM AUTHOR]

• NiO-CMD catalyst has shown potential bi-functional deoxygenation catalyst due to high capacity in removing oxygen compound to produce high quality of green fuel. • Synergistic effects of bi-functional NiO-CaO/MgO (acid-base) properties favored deoxyegnation pathways. • NiO doped Malaysian Dolomite restricted coke formation and improved product selectivity. • NiO-CMD catalyst had catalyzed simultaneous cracking- deoxygenation reaction. This study investigates the multi-objective optimization of reaction parameters with response surface methodology (RSM) with central composite design (CCD) for the deoxygenation of waste cooking oil (WCO) over low cost-modified local carbonate mineral catalyst (NiO-Malaysian dolomite) into green fuel in the range of gasoline, kerosene and diesel. RSM was performed to study the effect of four operating parameters: temperature (390–430 °C), time (30–120 min), catalyst loading (1–10 wt%) and nitrogen flow rate (50–300 cm3/min). The results indicate that for maximum WCO conversion, deoxygenated oil and product yield, the optimum parameters of the deoxygenation reaction were at 410 °C, 60 min, 5.50 wt% of catalyst loading, and 175 cm3/min of N 2. The green fuel properties testing (density, kinematic viscosity, flash point, cloud point, pour point, sulfur, carbon residue, cetane index, oxidation stability, acid value, iodine value and calorific value) and GC–MS analysis show that the product oil meets almost all the requirements of green diesel fuel and hydrocarbon biofuel standards for fuel application while the quadratic model proposed agreed with the experimental data (95% confidence) which indicates that the RSM can adequately predict the reaction products. [ABSTRACT FROM AUTHOR]

A convenient new method has been developed for preparation a series of 3-(substituted benzyl)piperidines by addition of substituted phenylmagnesium bromide to pyridine-3-carboxaldehyde followed by one pot deoxygenation and heteroaromatic ring saturation in the presence of palladium catalyst. [Copyright &y& Elsevier]