Catalysts For Hydrodeoxygenation Research Articles

Correction to “Porous Organic Polymer-Driven Evolution of High-Performance Cobalt Phosphide Hybrid Nanosheets as Vanillin Hydrodeoxygenation Catalyst”

Hydrodeoxygenation (HDO) is a promising route for the upgrading of bio-oils to eco-friendly biofuel produced from lignocellulose. Herein, we report the sequential synthesis of a hybrid nanocatalyst CoxP@POP, where substoichiometric CoxP nanoparticles are distributed in a porous organic polymer (POP) via solid-state phosphidation of the Co3O4@POP nanohybrid system. We also explored the catalytic activity of the above two nanohybrids toward the HDO of vanillin, a typical compound of lignin-derived bio-oil to 2-methoxy-4-methylphenol, which is a promising future biofuel. The CoxP@POP exhibited superior catalytic activity and selectivity toward desired product with improved stability compared to the Co3O4@POP. Based on advanced sample characterization results, the extraordinary selectivity of CoxP@POP is attributed to the strong interaction of the cation of the CoxP nanoparticle with the POP matrix and the consequent modifications of the electronic states. Through attenuated total reflectance-infrared spectroscopy, we have also observed different interaction strengths between vanillin and the two catalysts. The decreased catalytic activity of Co3O4@POP compared to CoxP@POP catalyst could be attributed to the stronger adsorption of vanillin over the Co3O4@POP catalyst. Also from kinetic investigation, it is clearly demonstrated that the Co3O4@POP has higher activation energy barrier than the CoxP@POP, which also reflects to the reduction of the overall efficiency of the Co3O4@POP catalyst. To the best of our knowledge, this is the first approach in POP-encapsulated cobalt phosphide catalyst synthesis and comprehensive study in establishing the structure-activity relationship in significant step-forwarding in promoting biomass refining.

High-Performance Evolution of Ni2P@Hierarchical HZSM-5 as the Guaiacol Hydrodeoxygenation Catalyst.

Hydrodeoxygenation (HDO) is one of the effective methods to upgrade biomass pyrolysis oil, but the development of a low-cost, high-performance HDO catalyst still faces enormous challenges. In this work, a facile and eco-friendly approach is developed to synthesize the Ni2P@hierarchical HZSM-5 catalyst. Structure and acidity of the catalyst can be controlled by simply adjusting the proportions of ammonia solution and the silicon to aluminum ratio, which are closely related to the performance of the catalyst. Experimental results reveal that the Ni2P@hierarchical HZSM-5 catalyst with Si/Al = 85 under NH3·H2O/Ni = 14 exhibits the highest activity of 98% guaiacol conversion, along with a 78.8% yield of cyclohexane (reaction conditions: 300 °C, 3 MPa H2). In addition, the guaiacol reaction network is provided.

Performance-screening of metal-impregnated industrial HZSM-5/γ-Al2O3 extrudates for deoxygenation and hydrodeoxygenation of fast pyrolysis vapors

Screening of catalysts for deoxygenation and atmospheric hydrodeoxygenation of fast pyrolysis vapors from biomass (wheat straw) was performed using a micro-scale setup. Steam-treated HZSM-5/Al2O3 extrudates were impregnated with metals by incipient wetness impregnation. 18 different metal modifiers (Pt, Pd, Ru, B, Li, Nb, Ga, Ca, Mg, Ce, Zn, Fe, Ni, Cu, Mo, Co, La, Zr) were tested, of which 14 were tested under inert atmosphere and 10 were tested in H2 containing atmosphere. The catalysts were evaluated based on the yield of individual product groups (incl. gas and coke), the oxygen content of the vapors, and the yield of vapor compounds containing, zero, one, and two-or-more oxygen atoms. The deactivation was monitored during 16 consecutive vapor pulses and cumulative product properties at B:C ∼4 were compared.In He atmosphere, a slight improvement of the deactivation behavior and the resulting cumulative vapor properties was observed for impregnation with Mg, B, Fe and Zr, but generally, the benefits were moderate or absent. Ga, Co, Ni, Fe, Cu, Mo, Nb, Pt, Ru, and Pd-modified HZSM-5/Al2O3 were tested in H2-containing atmosphere. A clear enhancement in catalytic activity resulted for Co, Fe, and Pd, achieving 21–26 % lower oxygen content compared to the unmodified HZSM-5/Al2O3. Even higher deoxygenation activity resulted for Ni, Mo, and Pt impregnated HZSM-5/Al2O3, achieving 35 %, 40 %, and 46 % lower oxygen content compared to HZSM-5/Al2O3. The results are attributed to a more favorable reaction chemistry such as hydrodeoxygenation and hydrogenation of coke precursors. Coke yields were clearly decreased compared to the parent HZSM-5/Al2O3 for the majority of the metal modifiers under H2 atmosphere, while under He atmosphere coke yields tended to be higher. Based on the high yields of gasoline-range hydrocarbons and considering catalyst costs, Mo-promoted HZSM-5/Al2O3 appears to be a promising catalyst that should be tested in hydrogen-containing atmosphere at larger scale allowing for further assessment of the liquid yield and properties.

Nature and Distribution of Cu and Pd Species in CuPd/TiO2-Na Bimetallic Catalysts for Glycerol Hydrodeoxygenation.

We demonstrated recently that CuPd/TiO2–Na bimetallic catalysts synthesized by sequential wet impregnation are active, selective, and stable for the hydrodeoxygenation (HDO) of glycerol into propylene glycol at low H2 pressure. The present study reports on the nature and distribution of Cu and Pd surface species in CuPd/TiO2–Na bimetallic catalysts using different scanning transmission electron microscopy techniques that supply cluster-specific alloying details. In particular, we used atomic-resolution Z-contrast imaging, X-ray energy-dispersive spectroscopy, and electron energy-loss spectroscopy. We also include X-ray photoelectron spectroscopy results. Our analysis shows that the metallic nanoparticles adopt mainly five different structures according to how the Cu and Pd atoms coordinate among themselves: a homogeneous CuPd alloy structure (45–61%), a Cu shell/CuPd core (15–23%), a smaller number of particles formed by Cu on the surface and Pd in the nucleus (10–17%), and there are also nanoparticles formed only by Pd (4–7%) or by Cu (8–13%). We determined that there is a inhomogeneous distribution of Cu and Pd in the bimetallic nanoparticles, with Cu being predominant on the surface (between 76 and 90% of the total area analyzed for each particle). Most bimetallic nanoparticles have sizes below 6 nm, the Pd monometallic nanoparticles are in the 2–4 nm range, whereas the monometallic Cu nanoparticles are larger than 8 nm. Bimetallic nanoparticles with sizes smaller than 6–7 nm are fundamentally made up of Cu0–Pd0 and Cu1+–Pd0. The nanoparticles with sizes greater than 7 nm consist of Cu2+ and Cu2+–Pd2+. Our obtained results also help describe reports about the activation of HDO by Pd–Cu in the absence of H2, an effect apparently not observed with other bimetallic systems.

Atomically Dispersed Co Catalyst for Efficient Hydrodeoxygenation of Lignin-Derived Species and Hydrogenation of Nitroaromatics

Single-atom catalysts (SACs) have attracted much attention due to their outstanding catalytic performance in heterogeneous catalysis. Here, we report a template sacrificial method to fabricate an a...

John Mondal

John Mondal

Biomass hydrodeoxygenation catalysts innovation from atomistic activity predictors.

Circular economy emphasizes the idea of transforming products involving economic growth and improving the ecological system to reduce the negative consequences caused by the excessive use of raw materials. This can be achieved with the use of second-generation biomass that converts industrial and agricultural wastes into bulk chemicals. The use of catalytic processes is essential to achieve a viable upgrade of biofuels from the lignocellulosic biomass. We carried out density functional theory calculations to explore the relationship between 13 transition metals (TMs) properties, as catalysts, and their affinity for hydrogen and oxygen, as key species in the valourization of biomass. The relation of these parameters will define the trends of the hydrodeoxygenation (HDO) process on biomass-derived compounds. We found the hydrogen and oxygen adsorption energies in the most stable site have a linear relation with electronic properties of these metals that will rationalize the surface's ability to bind the biomass-derived compounds and break the C-O bonds. This will accelerate the catalyst innovation for low temperature and efficient HDO processes on biomass derivates, e.g. guaiacol and anisole, among others. Among the monometallic catalysts explored, the scaling relationship pointed out that Ni has a promising balance between hydrogen and oxygen affinities according to the d-band centre and d-band width models. The comparison of the calculated descriptors to the adsorption strength of guaiacol on the investigated surfaces indicates that the d-band properties alone are not best suited to describe the trend. Instead, we found that a linear combination of work function and d-band properties gives significantly better correlation. This article is part of a discussion meeting issue 'Science to enable the circular economy'.

Micro-pyrolyzer screening of hydrodeoxygenation catalysts for efficient conversion of straw-derived pyrolysis vapors

Catalyst screening at micro-scale was performed for atmospheric hydrodeoxygenation (HDO) of fast pyrolysis vapors from biomass (wheat straw). The performance of TiO2-supported Pt and MoO3 catalysts and ZrO2 and TiO2-supported WO3 catalysts was compared to industrial Mo- and NiMo based catalysts. In addition, the HDO activity of an industrial HZSM-5/γ-Al2O3 extrudate promoted by MoO3 was investigated. In comparison with unpromoted acidic catalysts such as HZSM-5/γ-Al2O3, decreased deactivation rates and coke yields were obtained with catalysts that are active in HDO. Mo-based catalysts showed a higher selectivity to aromatics compared to aliphatics, while vapor upgrading with Pt/TiO2 favored aliphatics, thereby achieving the highest effective hydrogen index of the non-condensed vapors amongst the tested catalysts. Bulk WO3 was active for deoxygenation (23 % oxygen removal), albeit to a lesser extent compared to bulk MoO3 (37 % oxygen removal). Compared at the same mass of bulk transition metal oxide, the TiO2-supported WO3 and MoO3 catalysts obtained nearly complete deoxygenation (86–96 % oxygen removal), again with the supported MoO3 being more active than the supported WO3 catalyst.For the production of renewable fuels and/or chemicals from biomass via HDO of pyrolysis vapors the catalyst cost directly influences the economy and sustainability of the process. Therefore, this study further investigated red mud, an abundantly produced industrial waste from aluminum industries, and bog iron as two low-cost transition metal catalysts that are rich in iron. These two catalysts were tested at 4 times higher loading (8 mg) than the high-performing catalysts (2 mg). Under these conditions, an oxygen removal of 51 % and 61 % at vapor carbon yields of 22 wt% C and 14 wt% C were obtained for bog iron and red mud, respectively. Both catalysts showed a high selectivity to monoaromatics and ketones. However, bog iron obtained a higher yield of ketones compared to red mud. In addition, phenolics were converted completely by red mud, indicating a higher activity compared to bog iron.

Hydrotalcite supported bimetallic (Ni-Cu) catalyst: A smart choice for one-pot conversion of biomass-derived platform chemicals to hydrogenated biofuels

The production of drop-in biofuels 2,5-dimethylfuran (DMF), 2,5-dimethyltetrahydrofuran (DMTHF) from biomass-derived hydrocarbons usually incorporates precious metals as a catalyst. Herein, we developed a bimetallic (Ni-Cu) supported on hydrotalcite (HT) catalyst and applied for catalytic hydrogenation of 5-hydroxymethylfurfural (HMF) and 2,5-bis(hydroxymethyl)furan (BHMF) to 2,5-dimethylfuran (DMF) and other valuable fuel additives at a relatively low temperature (85–130 °C) and pressure (6–20 bar). The effect of other process parameters like reaction time, solvent and catalyst loading on DMF yield was also investigated. Ni-Cu/HT was found to be exceptionally active and selective catalyst for hydro-deoxygenation of HMF to DMF and other high-energy furanics. Ni-Cu/HT was applied under mild reaction condition for hydrogenation of BHMF to DMF and 100% BHMF conversion and 83% DMF yield was obtained at 85 °C and 6 bar hydrogen pressure and 100 mg catalyst loading. 78% over-hydrogenated product (DMTHF) yield was observed at higher catalyst loading (200 mg) at 130 °C. The excellent activity of Ni-Cu/HT catalyst for hydrogenation and deoxygenation is attributed to synergistic-cooperation of Ni and Cu and metal stability owing to hydrotalcite support. Moreover, the acid-base properties of HT also contributed to superior activity of Ni-Cu/HT catalyst by facilitating HMF, BHMF and formic acid adsorption and activation and by promoting hydrogenolysis of C-O ester bond. A detailed characterization of as-synthesized Ni-Cu/HT by TPR, BET, XPS, TEM, HRTEM, FESEM, EDX, powder XRD and FTIR techniques was carried out to examine its structural and morphological features.

Hydrodeoxygenation of benzyl alcohol on transition-metal-containing mixed oxides catalysts derived from layered double hydroxide precursors

M-MgAlO mixed oxide catalysts were prepared by controlled thermal decomposition of layered double hydroxides (LDH) precursors and were tested in the hydrodeoxygenation of benzyl alcohol. LDH with Mg/Al = 3 and 10 at. % M with respect to cations (M = Mn, Fe, Co, Ni, Cu and Zn) were obtained by coprecipitation. A second series of copper-containing catalysts with copper content from 5 to 20 at. % was also prepared. The solids were characterized by X-ray diffraction, N2 adsorption/desorption, temperature-programmed reduction in H2 atmosphere, temperature-programmed desorption of CO2. The influence of the transition metal and, for the copper-containing samples, of the copper loading, reaction temperature, reaction time, amount of catalyst and reduction pre-treatment on the catalytic performance were investigated. With 97% alcohol conversion and 96% selectivity to toluene, Cu15MgAlO is the best hydrodeoxygenation catalyst. It was also tested in the hydrodeoxygenation of 1-heptanol.

Mechanism of Dibenzofuran Hydrodeoxygenation on the Surface of Pt(111): A DFT Study

Catalytic hydrodeoxygenation is an efficient method to upgrade the quality of low-temperature coal tar and coal liquefied oil. However, only limited researches are performed on the mechanism of hydrodeoxygenation and, therefore, innovation of more efficient and stable catalysts is less progressed and still remains a challenging subject. In this study, density functional theory calculations are carried out to get a deeper insight in the mechanism of dibenzofuran hydrodeoxygenation on the Pt(111) surface. Calculated energies and activation barriers indicate that five-membered-ring opening of tetrahydrodibenzofuran is easier than that of hexahydrodibenzofuran. Then, the generated intermediate can be preferentially hydrogenated through a non-consecutive pathway to 2-cyclohexylphenol, and would result in multiple radical species. The dehydroxylation of that intermediate formed by adding five hydrogen atoms to the phenyl ring of 2-cyclohexylphenol shows a moderate reaction barrier of 1.07 eV; whereas, dehydroxylation of cyclohexylcyclohexanol needs a higher energy barrier of 2.04 eV. For the hydrodeoxygenation of dibenzofuran on the Pt(111) surface, the target product bicyclohexane is most likely to be formed through a radical intermediate. This investigation may provide a potent theoretical guidance to design new catalyst for hydrodeoxygenation of coal to liquid.

Ni/hierarchical ZSM-5 zeolites as promising systems for phenolic bio-oil upgrading: Guaiacol hydrodeoxygenation

Hierarchical ZSM-5 with mesopores were derived from seed directing crystalline process. The efficient encapsulation of nickel metal was achieved by a simple incipient wetness impregnation method, and a stable Ni/hierarchical ZSM-5 hydrodeoxygenation (HDO) catalyst was fabricated. The synthesized catalysts were characterized by XRD, N2-adsorption, FTIR, H2-TPR, NH3-TPD and TEM and were further tested for the hydrodeoxygenation of bio-derived guaiacol. Nickel particle size of about 6 nm and strong metal-support interaction were found for Ni/H-Z5 catalysts. It was discovered that the hydrodeoxygenation activity of the catalyst can be greatly improved by mesopores and strong acid sites. The reaction pathways were carefully studied to elucidate the effect of mesopores and acid sites. The Ni/ZSM-5 catalyst can be recycled seven times without loss of its initial selectivity.

Phosphoric acid enhancement in a Pt-encapsulated Metal-Organic Framework (MOF) bifunctional catalyst for efficient hydro-deoxygenation of oleic acid from biomass

The Pt-doped H3PO4@MIL-101Cr catalysts, with a series of phosphoric acid concentrations, were successfully synthesized using the double-solvent method for efficient hydrodeoxygenation (HDO) of fatty acid. The phosphoric acid modification of 1%Pt/MIL-101 enhanced the catalytic performance of HDO conversion of oleic acid in the gas phase with a 1.5–11 times higher turnover frequency (TOF) over metal site compared to the original Pt/MIL-101 catalyst. Moreover, the increase in the number of the moderate acid sites facilitates the decarbonylation/carboxylation compared to the hydrodeoxygenation reaction, based on the gradual increase in the ratio of nC17/nC18 due to the significant increase of the moderated Brønsted acid site. The FE-TEM and CO chemisorption measurements demonstrated that the Pt nanoparticles were highly dispersed on the support, and that they shifted to a larger size distribution due to the competitive adsorption between the acid site and metal site, with diameters in the range of 1.72–3.89 nm. The catalytic stability of a phosphoric acid modified- catalyst was maintained above 75% for 24 h of the HDO reaction. The application of phosphoric acid – MOF-based catalysts for the HDO of a model fatty acid compound was demonstrated for the first time, to the best of our knowledge, exhibiting an efficient catalyst system for HDO in a gas-phase process.

Synergistic effect with and without Ni metal over ZSM-5/SAPO-11 catalyst in hydrodeoxygenation of palm oil

Hydrodeoxygenation (HDO) of palm oil by catalytic for biofuels has attracted the researchers in the recent years. Currently available catalysts are typically intensive on sulfided CoMo and NiMo catalysts, which certainly modeled by the sulfur contamination in the final liquid product. Consequently, exploring the non-sulfured catalyst is still vulnerable challenge and has ultimate importance. In this paper, sulfur free catalyst with and without Ni based SAPO-11/HZSM-5 is synthesized according to incipient wetness impregnation method. The prepared catalyst was tested by performing HDO of palm oil for product selectivity. Different analytical techniques were used like: XRD, FESEM, Pyridine-FTIR and H2-TPD to explore the physicochemical properties of the novel catalyst. In addition, Ni supported ZSM-5/SAPO-11 catalyst with medium acidity showed greater properties because of the synergistic effect of Ni metal and acidic support than the catalyst without Ni support. The results showed that the, catalyst acidity has suggestively inclined the catalytic performance and product selectivity. The maximum selectivity of biofuel was achieved with ZSM-5/SAPO-11 over Ni support under the mild reaction condition at 350°C is indicating its auspicious part in this reaction. The acquired results determined that the metal and acid sites showed crucial role for the development of an effective catalyst for HDO of palm oil over Ni supported catalyst.

Ruthenium triphos complexes [Ru(X(CH2PPh2)3-κ3-P)(NCCH3)3](OTf)2; X = H3C-C, N) as catalysts for the conversion of furfuryl acetate to 1,4-pentanediol and cyclopentanol in aqueous medium

The ruthenium complexes [Ru(H3CC(CH2PPh2)3-κ3-P)(NCCH3)3](OTf)2 (1, (H3CC(CH2PPh2)3 = triphos) and [Ru(N(CH2PPh2)3-κ3-P)(NCCH3)3](OTf)2 (2, N(CH2PPh2)3 = N-triphos) have been evaluated as homogeneous ionic hydrogenation catalysts for the catalytic hydrodeoxygenation of furfuryl alcohol and furfuryl acetate to 1,4-pentanediol and cyclopentanol in aqueous media reaction mixtures. For furfuryl alcohol, only marginal yields of 1,4-pentanediol could be achieved with mass balance deficiencies due to humin formation ranging from 67% to 90%. Attempts to improve the catalytic activity of 2 by enhancing its water solubility by nitrogen protonation and (or) methylation failed. Employing the less self-reactive furfuryl acetate as the substrate substantially diminishes humin formation, yielding up to 43% of 1,4-pentanediol and 19% of cyclopentanol (via Piancatelli rearrangement) with 1 and up to 33% of 1,4-pentanediol and 5% of cyclopentanol with 2. A design of experiments study was used to determine and compare the yield responses of the multiple parallel reaction channels with 1,4-pentanediol, cyclopentanol, and humins as a function of reaction temperature, time, catalyst load, and substrate concentration. This explores the correlations between these parameters and their impact on the reaction outcome and suggests an extremely complex overall reaction cascade of interdependent pathways of both acid- and metal-catalyzed steps with some significant differences emerging between the two catalysts.

Guaiacol hydrodeoxygenation over Pd catalyst with mesoporous ZSM-5 support synthesized by solid-state crystallization

Mesoporous structure is important to promote mass transport and active site utilization of zeolites when used in reactions involving bulky molecules. However, their conventional hydrothermal synthesis is energy and labor intensive, requiring high-pressure operation, and lengthy heating a huge amount of alkaline liquid. We successfully synthesized new mesoporous zeolites, Meso-ZSM-5, via solid-state crystallization of dry aluminosilicate nanogels. Neighbor developing nanocrystals further joint at edges, creating connected, inter-lattice mesoscale pathway in the finished single crystalline zeolites. Palladium was further loaded on these zeolites to form a bi-functional catalyst (Pd/Meso-ZSM-5). When used in the hydrodeoxygenation (HDO) of guaiacol, a major bio-oil compound with disappointing conversion and severe coking issue over many HDO catalysts, Pd/Meso-ZSM-5 exhibits superior guaiacol conversion and product distribution when compared with those supported on conventional microporous ZSM-5 counterparts. This is attributed to the improved diffusion and accessibility of active sites inside Meso-ZSM-5 with its unique hierarchically porous structure. Ring saturated hydrocarbons are largely produced at 200 °C when hydrogenation dominates while alkaylated aromatics become major HDO products as deoxygenation becomes favorable at 250 °C. These encouraging results may ignite the wide use of these mesoporous zeolites in many other reactions in both traditional fossil fuel and emerging renewable energy fields.

Ruthenium-containing SBA-12 catalysts for anisole hydrodeoxygenation

Abstract Hexagonally ordered mesoporous silica SBA-12 catalysts containing various amounts of Ru (1 or 3 wt.%) were obtained by wet impregnation. These catalysts were thoroughly characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and low-temperature nitrogen adsorption/desorption (N2 ads/des). Anisole conversion was measured over catalysts at different process conditions, where the process temperature was 90−130 °C and the hydrogen pressure – 25−60 bar. Prior the experiments the process was optimized, i.e., the amount of catalyst used in the reaction and the time of reaction were adjusted. This study shows a significant effect of hydrogen pressure and process temperature on the hydrodeoxygenation of anisole, the conversion of which increased (16–100 %) with both increasing parameters. For all the catalysts studied, the highest selectivity was obtained for two main reaction products, methoxycyclohexane and 1-methoxycyclohexene. Along with increasing conversion of anisole, the selectivity to the main reaction product - methoxycyclohexane generally increased (65–96 %) reducing the amount of 1-methoxycyclohexene (0–27 %).

Nanostructured Carbon Material Effect on the Synthesis of Carbon-Supported Molybdenum Carbide Catalysts for Guaiacol Hydrodeoxygenation

The impact of using different nanostructured carbon materials (carbon nanofibers, carbon nanotubes, graphene oxide and activated carbon) as a support for Mo2C-based catalysts on the hydrodeoxygenation (HDO) of guaiacol was studied. To optimise the catalyst preparation by carbothermal hydrogen reduction (CHR), a thermogravimetric study was conducted to select the optimum CHR temperature for each carbon material, considering both the crystal size of the resulting β-Mo2C particles and the extent of the support gasification. Subsequently, catalysts were prepared in a fixed bed reactor at the optimum temperature. Catalyst characterization evidenced the differences in the catalyst morphology as compared to those prepared in the thermogravimetric study. The HDO results demonstrated that the carbon nanofiber-based catalyst was the one with the best catalytic performance. This behaviour was attributed to the high thermal stability of this support, which prevented its gasification and promoted a good evolution of the crystal size of Mo species. This catalyst exhibited well-dispersed β-Mo2C nanoparticles of ca. 11 nm. On the contrary, the other supports suffered from severe gasification (60–70% wt. loss), which resulted in poorer HDO efficiency catalysts regardless of the β-Mo2C crystal size. This exhibited the importance of the carbon support stability in Mo2C-based catalysts prepared by CHR.

Synergistic effects between Cu and Ni species in NiCu/γ-Al2O3 catalysts for hydrodeoxygenation of methyl laurate

Cu was introduced into Ni/γ-Al2O3 to prepare mesoporous NixCuy/γ-Al2O3 catalysts with different Ni and Cu contents. H2-TPR, XRD, BET, H2-TPD, and in-situ XPS were used to study the physicochemical properties of the prepared NixCuy/γ-Al2O3 catalysts. The catalytic performances of NixCuy/γ-Al2O3 catalysts were evaluated by methyl laurate catalytic hydrodeoxygenation (HDO) reaction. The NixCuyO/γ-Al2O3 precursors can be reduced to Ni0, Cu0, and NiCu alloy active species by H2 at 420°C. Formed NiCu alloy can effectively promote the electronic effect between Ni and Cu, and enhance the adsorption and activation abilities of the corresponding catalyst for the reactant molecules. The Ni active sites preferentially catalyzes the decarbonylation/carboxyl (DCO) reaction in the deoxygenation of methyl laurate, while the HDO pathway is predominant on the Cu active sites. The deoxygenation pathway obviously changes from DCO to HDO at the mole ratio of Ni/Cu lower than 3/7, and the main deoxygenation products change from C11 to C12 alkane. At the H2/Oil ratio of 500N, the space velocity (SV) of 1.5 h−1, H2 pressure(P) of 2 MPa, and the reaction temperature of 380°C, the Ni3Cu7/γ-Al2O3 catalyst shows the best methyl laurate DCO properties. And methyl laurate conversion and the main deoxygenation products C11 alkane selectivity can reach 98.3 and 87.4%, respectively. Moreover, Ni3Cu7/γ-Al2O3 catalyst also exhibits good stability.

Parametric Studies on Hydrodeoxygenation of Rubber Seed Oil for Diesel Range Hydrocarbon Production

Hydrodeoxygenation (HDO) is considered as a substantial path for cleaner production of fatty acids and triglycerides into diesel range hydrocarbons (DRHs) (C15–C18) generally identified as green diesel fuel. Heterogeneous catalysis suggests a supplementary approach for the conversion of biomass into significant biochemicals possibly selective hydrocarbons by an inventive method. The present study reveals the optimization of reaction parameters for the process of HDO of rubber seed oil (RSO) over the transition metal NiMo/γ-Al₂O₃ (NMA) catalyst (designed via sonochemical co-impregnation approach) into DRHs, that is, n-C15-n-C18. The comprehensive studies have been performed to investigate the parametric effects employing response surface methodology using central composite design. The experimental design was conducted on the four most influential operating factors, namely, temperature within the range of 300–400 °C, weight hourly space velocity (WHSV) (1–3 h–¹), H₂/oil ratio (400–1000 N (cm³/cm³)), and pressure (30–80 bar), for triglyceride conversion and DRH yield. All the experimental runs were performed in continuous process using a fixed bed tubular reactor over the NMA catalyst. The product analysis showed that triglycerides are completely hydrodeoxygenated into DRHs with an optimum production of 84.94 wt % yield led by prime reaction conditions at a temperature of 400 °C, WHSV of 1 h–¹, pressure of 80 bar, and H₂/oil ratio of 400 N (cm³/cm³). The parametric interaction between temperature and WHSV has significantly influenced the diesel yield. The investigations validated that HDO tracked the corresponding reaction condition in competitive mode and obligated the diverse optimum and limiting reaction conditions. In addition, deactivation of the catalyst study was performed at the optimized reaction condition. The catalyst was found to be active until 18 h without bringing to sulfidization process with 80% diesel yield and 100% triglyceride conversion. The slight deactivation of the catalyst is observed, with a very small amount coke deposition even after 18 h of time on stream at the optimized reaction condition. The novelty of the present study lies in the performance of sonochemically synthesized catalyst for HDO of RSO to produce green diesel and to optimize the reaction condition and catalysts deactivation performance at optimized reaction conditions.