Catalytic Deoxygenation Reaction Research Articles

The catalytic deoxygenation reaction temperature and N2 gas flow rate influence the conversion of soybean fatty acids into Green Diesel

BackgroundGreen diesel is a promising alternative as a petroleum replacement given the worldwide demand for petroleum fuel. Environmental issues have drawn public attention and concerns towards advancing renewable energy development. A catalytic deoxygenation (deCOx) was carried out to produce green diesel from soybean oil (SO) using a low-cost NiO-doped calcined dolomite (NiOCD) catalyst. MethodThe structure, chemical composition and morphology of NiOCD were comprehensively characterized by XRF, BET, TPD-CO2, SEM and TEM. In this study, the effect of two operating parameters, reaction temperature and flow rate of nitrogen, was discovered using a one-factor-at-a-time (OFAT) optimisation study. In addition, the life cycle cost analysis (LCCA) of stepwise catalyst preparation and green diesel production has been performed. Significant findingsAn optimal reaction temperature of 420 °C was found to provide the highest yield of green diesel (47.13 wt.%) with an 83.51% hydrocarbon composition. The ideal nitrogen flow rate, however, was found to be 50 cm3/min, which produced 41.80 wt.% of green diesel with an 88.63% hydrocarbon composition. The deoxygenation reaction was significantly impacted by both reaction temperature and nitrogen flow rate. According to LCCA, NiOCD catalyst has potential to lower the overall cost of producing green diesel compared to commercial zeolite catalysts.

Production of green diesel from waste cooking oil via catalytic deoxygenation reaction using metal doped eggshell catalyst

Abstract Green diesel production via catalytic deoxygenation of waste cooking oil (WCO) over metal doped eggshell catalyst was investigated in this work. The catalyst was prepared through liquid-liquid precipitation of 5 transition metal solutions and ground eggshell (ES) as the catalyst support. The prepared catalyst, Fe-ES, Cu-ES, Co-ES, Zn-ES, and Ni-ES were characterized using BET surface area and Scanning Electron Microscopy (SEM) analysis. BET surface area data and SEM images of the catalyst shows a promising catalyst physical properties that tailor to the deoxygenation reaction. Gas Chromatography Mass Spectrometry (GCMS) was used to determine the hydrocarbon composition of the oil yield product from the reaction. The reaction also produces gas, soap and liquid acid phase while the remaining unreacted WCO becomes coke. The percentage of all products and coke were calculated using mass balance. Deoxygenation of WCO with Ni-ES catalyst produced highest oil yield at 61.6% with the hydrocarbon content of 56.11%. Ni-ES also produced 22.9% coke; the least percentage compared to other catalyst. The findings proved that Ni-ES catalyst exhibited the highest conversion of WCO into gas and liquid product with a greater yield of oil and minimal coke formation. These findings demonstrate the feasibility and practicality of using eggshell catalysts as substitutes for commercial catalysts in green diesel production.

Simulation of a catalytic deoxygenation reaction of fatty acids to produce biohydrocarbons and evaluation of the influence of reaction parameters on the conversion and selectivity of products

Nowadays, there has been an urgency in the search for sustainable energy sources, such as those derived from biomass. This search is not only limited to minimizing greenhouse gas emissions but is also related to the increasing scarcity of fossil fuels. This work aims to investigate and analyze the production of bio-hydrocarbons from fatty acids through the simulation of the deoxygenation reaction by the DWSim software. In this simulation, a continuous catalytic deoxygenation reactor of the stirred tank with fluidized bed type was selected, aiming to understand the influence of operating parameters on this reaction. The parameters evaluated were temperature, pressure, hydrogen feed, and catalyst mass. For this simulation, hydrogen and stearic acid were chosen as feedstocks, focusing on the heptadecane and octadecane production. The rate law was chosen based on an extensive literature review, as well as reaction conditions. The kinetic model used as a reference was based on reactions of stearic acid and hydrogen in the presence of NiMo/Al2O3 as a catalyst. A stearic acid feed of 2.4 x 104 m3 year-1 was used as a base, representing the average feed of fatty raw material practiced in biodiesel plants located in the state of Minas Gerais, Brazil. From the variation of these parameters for a sensitivity analysis, with conversion as the key response, the following optimal operating conditions were defined: temperature of 650 K, pressure of 50 bar, molecular hydrogen feed of 4.1 x 10-3 m³ s-1, and catalyst mass of 8 kg. Under these new circumstances, the conversion of stearic acid reached a value of 99.23 %. The simulation of this reaction allowed us to understand the effect of the main reaction parameters on the reaction products, proved to be an important and robust tool to be used in projects and feasibility analyses of plants and biorefineries.

Green Diesel Production by Catalytic Hydrodeoxygenation of Vegetables Oils.

Non-renewable fossil fuels and the air pollution associated with their combustion have made it necessary to develop fuels that are environmentally friendly and produced from renewable sources. In addition, global warming and climate change have brought to the attention of many countries the need to develop programs and reforms, such as the 2030 Agenda of the United Nations and the European Green Deal, that finance and promote the conversion of all socio-economic activities in favor of sustainable and environmentally friendly development. These major projects include the development of non-polluting biofuels derived from renewable sources. Vegetable oils are a renewable source widely used to produce biofuels due to their high energy density and similar chemical composition to petroleum derivatives, making them the perfect feedstock for biofuel production. Green diesel and other hydrocarbon biofuels, obtained by the catalytic deoxygenation of vegetable oils, represent a sustainable alternative to mineral diesel, as they have physico-chemical properties similar to derived oil fuels. The catalyst, temperature, hydrogen pressure, and the type of vegetable oil can influence the type of biofuel obtained and its properties. The main aspects discussed in this review include the influence of the catalyst and reaction conditions on the catalytic deoxygenation reaction.

Multiple-objective optimization in green fuel production via catalytic deoxygenation reaction with NiO-dolomite catalyst

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 N2. 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.

Vanadium Pyridonate Catalysts: Isolation of Intermediates in the Reductive Coupling of Alcohols.

The reductive coupling of alcohols using vanadium pyridonate catalysts is reported. This attractive approach for C(sp3)-C(sp3) bond formation uses an oxophilic, earth-abundant metal for a catalytic deoxygenation reaction. Several pyridonate complexes of vanadium were synthesized, giving insight into the coordination chemistry of this understudied class of compounds. Isolated intermediates provide experimental mechanistic evidence that complements reported computational mechanistic proposals for the reductive coupling of alcohols. In contrast to previous mononuclear vanadium(V)/vanadium(III)/vanadium(IV) cycles, this pyridonate catalyst system is proposed to proceed by a vanadium(III)/vanadium(IV) cycle involving bimetallic intermediates.

Ni, Zn and Fe hydrotalcite-like catalysts for catalytic biomass compound into green biofuel

Abstract In this study, the deoxygenation pathway was proposed to eliminate oxygen species from biomass-derived oil, thereby producing a high quality of hydrocarbon chains (green fuel). The catalytic deoxygenation reaction of bio-oil model compound (oleic acid) successfully produced green gasoline (C8–C12) and diesel (C13–C20) via activated hydrotalcite-derived catalysts (i.e. CMgAl, CFeAl, CZnAl and CNiAl). The reaction was performed under inert N2 condition at 300 °C for 3 h, and the liquid products were analysed by GC–MS and GC–FID analyses to determine the hydrocarbon yield and product selectivity. The activity of the catalysts towards the deoxygenation reaction presented the following increasing order: CNiAl > CMgAl > CZnAl > CFeAl. CNiAl produced a hydrocarbon yield of up to 89 %. CNiAl demonstrated the highest selectivity with 83 % diesel production, whereas CMgAl showed the highest gasoline selectivity with 30 %. These results indicated that catalysts with a high acidic profile facilitate C–O cleavage via deoxygenation, producing hydrocarbons (mainly diesel-range hydrocarbons). Meanwhile, highly basic catalysts exhibit significant selectivity towards gasoline-range hydrocarbons via cracking and lead to the occurrence of C–C cleavage. The large surface area of CNiAl (117 m2 g−1) offered high approachability of the reactant with the catalyst’s active sites, thereby promoting high hydrocarbon yield. Consequently, the hydrocarbon yield and selectivity of the deoxygenation products were predominantly influenced by the acid–base properties and structural behaviour (porosity and surface area) of the catalyst.

Deoxygenation mechanism of methyl butyrate on HZSM-5: A density functional theory study

The catalytic cracking of fatty acid esters is of great importance for the utilization of biomass. Here, the Gibbs energy barriers for the multistep catalytic deoxygenation reaction of methyl butyrate in HZSM-5 zeolite were systematically investigated via density functional theory (DFT). All the rate-determining steps of the different reaction pathways together with the possible reaction intermediates were determined. The optimal preliminary cleavage reaction of methyl butyrate on HZSM-5 zeolite were CH3CH2CH2CO2CH3 → CH3CH2CH2C+(O) + CH3OH and CH3CH2CH2CO2CH3 → CH3CH2CH2CO2H + CH3+. The initial cleavage products (butyryl carbocation, methanol, and butyric acid) subsequently formed alkanes through a series of dehydration and decarboxylation as well as nucleophilic addition reactions. The butanone intermediate, which was the determining factor for carbon chain growth, tended to form longer carbonyl cations with alkyl alkoxides, followed by decarbonylation reactions. In addition, the difficulty of the nucleophilic addition reaction and decarbonylation reaction depended on the stability of the carbocations in the transition state. The reaction mechanism revealed here may pave the way to the design of highly efficient catalysts for the catalytic cracking of biomass.

Catalytic deoxygenation of waste soybean oil over hybrid catalyst for production of bio-jet fuel: in situ supply of hydrogen by aqueous-phase reforming (APR) of glycerol

A one-pot reaction was performed to produce oxygen-free saturated hydrocarbons via the catalytic deoxygenation and hydrogenation of waste soybean oil over a hybrid catalyst (Pd/C and NiO/γ-Al2O3). We utilized in situ hydrogen generated from a reforming reaction of glycerol, a byproduct of triglyceride hydrolysis, for the one-pot reaction to produce hydrocarbons. When NiO/γ-Al2O3 (2 g) was used along with Pd/C (1 g), most of the unsaturated free fatty acids (FFAs) were hydrogenated into saturated FFAs, and the percentage of desirable hydrocarbons in the liquid product increased, in contrast to the case when only Pd/C (1 g) was used. This result means that using a hybrid catalyst is better for promoting the catalytic deoxygenation reaction than increasing the degree of loading of Pd/C, and suggests that it should be possible to decrease the amount of precious metal catalysts to be used for deoxygenation reaction.

The surface and catalytic chemistry of the first row transition metal phosphides in deoxygenation

The proven utility of transition metal (TM) phosphides in catalytic deoxygenation reactions and their ability to preserve unsaturation or aromaticity in products has suggested the materials exhibit unique surface chemistry towards C, O, and H.

Production of bio-jet fuel range alkanes from catalytic deoxygenation of Jatropha fatty acids on a WOx/Pt/TiO2 catalyst

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]/TiO2 was used for the deoxygenation of stearic acid and Jatropha fatty acid derived from Jatropha oil by hydrolysis. Tungsten addition to the Pt/TiO2 showed remarkably enhanced performance, a degree of deoxygenation of 86%, which is more than two times higher than that of the Pt/TiO2, even though the WOx/TiO2 had almost no activity for deoxygenation reaction. The enhanced Pt-related hydrogen uptake, measured by H2-TPR, and XPS analysis showed the intimate contact of tungsten with Pt nanoparticles supported on TiO2. This tight contact allows for easier CC cleavage over Pt nanoparticles and this is assisted by the strong bonding between tungsten and oxygen in the reactant, resulting in more C17 hydrocarbon production on the WOx/Pt/TiO2.

Catalytic hydroconversion of pyrolytic bio-oil: Understanding and limiting macromolecules formation

Fast pyrolysis followed by catalytic hydroconversion is a value chain aimed to transform lignocellulosic biomass into biofuel or chemicals. During hydroconversion, desired catalytic deoxygenation reactions are in competition with thermal side reactions like condensation or oligomerization. These undesired pathways lead to high molecular weight compounds (i.e. macromolecules) that are responsible for catalyst deactivation and severe plugging of the reactor. We investigate here the impact of a phenolic compound on the formation of these macromolecules. Catalytic hydroconversion of a fast pyrolysis bio-oil and a bio-oil/guaiacol (50/50 wt%) mixture were carried out in a batch reactor using a NiMo/alumina catalyst. An extended analytical strategy has been developed involving size-exclusion chromatography (SEC) and liquid state 13C NMR dedicated to the in depth characterization of effluents as well as physicochemical analysis of the fresh and used catalyst (XRD, Hg porosimetry, N2 physisorption, STEM). This strategy allowed bringing new insights on aromatic structures larger than 1000 g.mol−1 and their formation mechanism. This formation can be chemically inhibited by the introduction of organic component such as guaiacol. This stabilization was mainly observed and explained at low temperature and short reaction time.

ChemInform Abstract: Catalytic Deoxygenation on Transition Metal Carbide Catalysts

AbstractReview: 110 refs.

Bio fuel production from crude Jatropha oil; addition effect of formic acid as an in-situ hydrogen source

The catalytic deoxygenation reaction of crude Jatropha oil (CJO) was carried out to produce oxy-free hydrocarbons in assistance with hydrogen in-situ produced from formic acid solution (30%) and addition effect of formic acid was discussed on the deoxygenation reaction and product distribution. Mixing of formic acid with reactant yielded higher oil conversion and higher selectivity to normal hydrocarbon (mainly C15 and C17) than those of the other cases (no mixing or water addition). Total surface area and total pore volume of used catalysts in the batch reactor followed the order Pd/C–formic acid solution>Pd/C–water>Pd/C–no co-reactant under constant conditions. Moreover, significantly higher degree of deoxygenation with a high initial resistance to catalyst deactivation was observed on Pd/C catalyst in the presence of formic acid during the continuous catalytic reaction. This means that addition of formic acid solution as the hydrogen donor is favorable the deoxygenation reaction and the initial deactivation of catalyst. As results of continuous deoxygenation reaction using the mixture of oil and formic acid, normal hydrocarbon in the liquid product was main product, about 97%, and the degree of deoxygenation was about 99.5%.

Influence of the Zeolite ZSM-5 on Catalytic Pyrolysis of Biomass via TG-FTIR

Bio-oil from the pyrolysis of biomass is an important renewable source for liquid fuel. However, the application of bio-oil has been severely restricted due to its high viscosity, acidity, and low heating value. Thus, it has been necessary to upgrade bio-oil for automobile fuel via catalytic deoxygenation reactions. Herein, the effects of the zeolite ZSM-5 on the pyrolysis of four biomass materials (corn cob, corn straw, pine powder, and cellulose) were investigated via TG-FTIR (thermogravimetric analyzer coupled with a Fourier transform infrared spectrometer) to better understand the working mechanism of ZSM-5. The contents of the products of H2O, CO, CO2, and the C-O, C=O, and OH groups evolved with increasing pyrolytic temperature were monitored by FTIR. It was found that the relative contents of the C-O and C=O groups were decreased under the catalysis of ZSM-5, while the formations of CO, H2O, and the OH containing compounds were promoted. To explain the regulations, reaction routes were speculated and the catalytic conversion mechanisms were deduced.

Phenol Deoxygenation Mechanisms on Fe(110) and Pd(111)

The catalytic deoxygenation of phenolic compounds has become a major area of interest in recent years because they are produced during the pyrolysis of lignin and are present in biofuels. Our previous work showed that a PdFe bimetallic catalyst was catalytically active for the deoxygenation of phenolics. To better understand and control the catalytic deoxygenation reaction of phenolics, the detailed surface reaction mechanisms are needed for phenol, a key intermediate in phenolic deoxygeantion. Here, we have examined five distinct reaction mechanisms for the deoxygenation of phenol on the Fe(110) and Pd(111) surfaces so as to identify the most likely deoxygenation mechanism on these surfaces. Our results show that the elementary phenol deoxygenation reaction step for each mechanism was highly endothermic on Pd(111), whereas the same mechanisms are exothermic on Fe(110). On the basis of the reaction energy studies, detailed mechanistic studies were performed on the Fe(110) surface, and it was found that the most energetically and kinetically favorable reaction mechanism occurs via the direct cleavage of the C–O bond.