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Selective oxidation of 5-hydroxymethylfurfual (HMF) to 2,5-furandicarboxylic acid (FDCA) as a bioplastics monomer is efficiently promoted by a simple system without noble-metal and base additives. In this work, graphene oxide (GO) was first synthesised by an electrochemical method with flexible graphite paper (FGP) as start carbon material, then, nitrogen-doped graphene (NG) layers encapsulated Cu nanoparticles (NPs) was prepared by one-step thermal treatment of GO supported Cu2+ in flowing NH3 atmosphere. Compared with NG supported Cu NPs prepared by the traditional impregnation method, enhanced catalytic activity was achieved over Cu/NG and an FDCA yield of 95.2% was achieved under mild reaction conditions with tert-butylhydroperoxide (t-BuOOH) as the oxidant. Control experiments with different catalysts and different addition procedure of t-BuOOH showed the yield of HMF and various intermediates during reaction. From the changing of intermediates concentrations and reaction rates, a reaction pathway through HMF-DFF-FFCA-FDCA was proposed. This work gives a more convenient, more green, more economical and effective method in encapsulated metal NPs preparation and high selectivity in HMF oxidation to FDCA under mild conditions.

The Ni/SBA-15 and Ni/TiO2 catalysts with 20 wt% nickel with different metal–support interaction strength were designed using ordered mesoporous silica (SBA-15) and TiO2 (P25). The Ni/SBA-15 and Ni/TiO2 catalysts with 20 wt% nickel were investigated using various characterization techniques. It was found that the Ni/SBA-15 and Ni/TiO2 catalysts with 20 wt% nickel possess different nickel particle size and different reducibility because of the different strength between nickel and support interaction. Both Ni/SBA-15 and Ni/TiO2 catalysts were tested for the hydrodeoxygenation reaction of a model bio-oil using a fixed-bed reactor at different evaluation conditions. It was found that under high hydrogen pressure (≥7 bar), both Ni/SBA-15 and Ni/TiO2 catalysts are highly efficient because the organic oxygen compound could be converted completely. And the product selectivity is very sensitive to the hydrogen pressure. Under low hydrogen pressure (3–5 bar) Ni/TiO2 catalyst show rather higher selectivity toward aromatic hydrocarbon as compared with Ni/SBA-15 catalyst. Lower hydrogen pressure and reaction temperature will be beneficial to the aromatic hydrocarbon production. It is very important to reduction for the H2 consumption cost. TiO2 is a very potential candidate support for the catalyst design aiming to the sustainable aromatic hydrocarbon production.

Graphene oxide (GO), prepared by the modified Hummers method, was applied as a highly active and selective solid acid catalyst for oxidative transformation of furfural (FAL) into succinic acid (SA)...

In this work, pyridinic-nitrogen-dominated nitrogen doped graphene with Cu incorporation (Cu/NG) are prepared via a facile and effective process. In prepared nitrogen doped graphene (NG), high nitrogen content up to 13.5 wt% was achieved and pyridinic-nitrogen dopant enriched to 11.9 at.%. Cu nanoparticles can be highly stabilized by NG materials and the stabilized Cu loading is linearly correlated with the pyridinic nitrogen content in NG. With Cu/NG as the catalyst and 2,2,6,6-tetramethyl-piperidin-1-oxyl (TEMPO) as co-catalyst, 5-hydroxymethylfurfural (HMF) was oxidized to 2,5-diformylfuran (DFF) in the new developed catalytic system under relative mild conditions (70 °C, 8 h) with high HMF conversion (99.8%) and DFF yield (99.2%). By various characterization and experimental data, Cu-N-C nano-centers were speculated to be the actives sites in catalytic oxidation of HMF. Comparison of high-resolution XPS spectra of N 1s between NG and Cu/NG material indicates the existence of strong interaction between Cu nanoparticles and pyridinic N. The developed catalytic system showed high efficiency in HMF oxidation and Cu/NG can be recycled for eight times without any obvious Cu leaching and catalytic activity loss.

Graphene oxide (GO) sheets are emerging as a new class of carbocatalyst, and also a perfect platform for metal-oxide catalyst assembling. The oxygen groups on either side of GO basal plane can be functioned as the anchor by employing GO as scaffolds. Vanadium-oxo nanosheets (VON) were assembled onto the surface of GO material from homogeneously dissolved VO(acac)2 solution via a facile route. Control experiments with different methods prepared graphene materials illustrate the nucleation and fabrication process of VON on GO surface with detailed TEM and XPS investigation. The evolution of oxygen groups in graphene material was also investigated. Hydroxyl/epoxy in GO sheets was considered to be important and favorable for the fabrication of VON on GO surface. The developed material was shown to be an efficient and recyclable heterogeneous catalyst for aerobic oxidation of 5-hydroxymethyfurfural (HMF) and furfural into maleic anhydride. Up to 90.9% yield of maleic anhydride from HMF and 59.9% from furfural were achieved under optimized reaction conditions, the reaction rate difference between HMF and FAL was studied on the basis of oxidation mechanism and their molecular structures.

Mesoporous silica-included heteropolyacids materials were synthesized and characterized by nitrogen sorption, XRD, FT-IR, TEM and NH3-TPD. Characterization results show that silica included heteropolyacids is a kind of Bronsted acid catalyst possessing large surface area, suitable pore structure, appropriate acid strength and high acid density. These materials are used as solid catalysts for the alkylation of phenol with cyclohexene. The mesoporous channel facilitates not only the dispersion of Bronsted acidity centers but also the transport of reactant and product molecules, thus leading to a significantly improved catalytic performance. Through adjusting the interaction between the support pore channel surface and heteropolyacid acive species, different acidity amount and strength can be obtained, leading to the tunable selectivity to the alkylation of phenol with cyclohexene. The improvement of reusability of silica-included HPA catalyst was related to the uniform dispersion of HPA and the enhanced interaction between HPA and the support. In six cycles of the catalyst, a stable activity could be mainttained.

This paper mainly explores the influence of different experiment factors on the angelica lactone self-aggregation process to synthesize C 10 , C 15 and C 20 self-aggregation products through Michael addition by base catalysis. Various experiment factors including types of catalysts, temperature, time and catalyst amounts are investigated in the angelica lactone self-aggregation process. And the possible mechanism of angelica lactone self-aggregation process catalyzed by carbonate is proposed. The results show that anhydrous potassium carbonate exhibits the higher efficiency and milder application conditions than other base catalysts. The different dominating products could be obtained by using anhydrous potassium carbonate under different experiment conditions. The optimal conditions for the angelica lactone dimer (C 10 ) are 10 wt% catalyst, 343 K and 30 min, and the maximal yield of dimer is 69.26%; the optimal conditions for the angelica lactone trimer (C 15 ) are 12 wt% catalyst, 333 K and 20 min, and the maximal yield of trimer is 49.89%; the optimal conditions for the angelica lactone tretramer (C 20 ) are 12 wt% catalyst, 343 K and 60 min and the maximal yield of tretramer is 62.46%.

The combination of benzoic acid and 2,2,6,6-teramethylpiperidin-1-oxyl (TEMPO) afforded an efficient catalytic system for the aerobic oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-diformylfuran (DFF) under certain conditions. The maximum conversion of 86.7 % for HMF was obtained with a nearly 77.8 % DFF yield at 1 mmol benzoic acid and 0.4 MPa oxygen pressure in acetonitrile. The aerobic oxidation ability of HMF into DFF depended on the electron density of the organic acid skeletal structure with the carboxyl group. Meanwhile, the catalyst system of benzoic acid/TEMPO also exhibited good performance for aerobic oxidation of other alcohols. Based on experimental results, we propose that the benzoic acid acted as the primary catalyst and TEMPO was the key co-catalyst, oxidized into oxoammonium cation through electron transport and then regenerated by a superoxide radical during the reaction.

The dehydration of fructose in aqueous and biphasic system was studied using heteropolyacids, immobilized in silica, as catalyst. The catalysts were characterized by ICP-AES, nitrogen sorption, NH3-TPD, TEM, FT-IR, XRD, and TGA. The effect of different parameters, such as reaction temperature, reaction time, catalyst loading and volume ratio of water with methyl isobutyl ketone (MIBK) was studied. Silica included tungstosilisic acid (HSiW) was found to function as an efficient catalyst for the transformation of fructose into 5-hydroxymethylfurfural in aqueous phase. Addition of MIBK into the reaction system can increase both of fructose conversion and HMF selectivity. Besides, MIBK showed a positive effect in increasing the stability of the catalyst by suppressing the formation and deposition of humins over catalyst surface. After the third catalysis cycles, a stabilization of the catalytic activity was observed.

Ce-containing SBA-15 materials with Ce/Si molar ratio ranging from 0 to 0.08 were prepared by mixing an acidic suspension of colloidal CeO 2 particles along with the surfactant during the synthesis of mesostructured silica. The obtained solids were characterized by powder X-ray diffraction (XRD), N 2 sorption isotherms, TEM, UV–vis, and Raman spectroscopy. Structural analyses confirmed that all the samples present a well-ordered hexagonal mesoporous structure, with larger pore diameter and volume than unmodified SBA-15 due to the incorporation of the lanthanide promoter. According to the characterization results different cerium species, namely dispersed Ce species and CeO 2 crystallites, are formed depending on the Ce/Si ratio of the Ce-SBA-15 materials. On the other hand, Ni/Ce-SBA-15 catalysts were prepared by wet impregnation of the mesoporous supports and the comparison of the different samples showed that the incorporation of Ce progressively enhances Ni dispersion. These catalysts were assayed for hydrotreating of anisole at temperatures in the 270–290 °C range and moderate hydrogen pressure (7 bar). Such process is relevant for the upgrading of bio-oils derived from the pyrolysis of lignocellulosic biomass. Catalytic activity tests reveal that conversion of anisole progressively improves with increasing Ce/Si ratio and exceeds 30% at 290 °C for the catalyst with Ce/Si = 0.08. In these conditions the main product is methoxycyclohexane in all cases. However, almost a two-fold increment of benzene yields can be obtained with Ce-promoted catalysts when compared to Ni/SBA-15. This enhancement of the selectivity towards aromatic is very promising for the development of a green route for the production of those chemicals.

2,5-hexanedione, a valuable platform chemical which is being broadly used in biofuel, medicinal chemistry and drug discovery, was synthesized from biomass derived dimethyl furane using a highly efficient biphasic system. In this biphasic systems, mineral acids (HCl, H2SO4 and H3PO4) dissolved in aqueous phase were used as hydrolysis catalysts. The hydrolysis reaction is suggested to take place at the interface between the aqueous and the organic phase. But more importantly, water-immiscible organic phase could continuously extract the in-situ produced 2,5-hexanedione from the interface to prevent the extended contact between the 2,5-hexanedione and the acids, thereby avoiding the oligomerization side reactions A yield of 99 % could be obtained when methyl isobutyl ketone (MIBK) was the organic phase in the biphasic system.

Co-containing catalysts supported on super-microporous Al2O3–ZrO2 (denoted as Co/AZ(X)) with different Al/Zr molar ratio (X) were prepared by impregnation method, and they were applied to the dehydrogenation of ethylbenzene with CO2 as soft oxidant. It was found that textural and chemical properties of Co/AZ(X) materials were strongly influenced by Al/Zr molar ratio. The catalytic performance of these materials highly depended on their physicochemical properties, and the 2.5Co/AZ(0.7) catalyst with an intermediate acidity, high surface area and high metal dispersion exhibited the best catalytic performance in the dehydrogenation of ethylbenzene with CO2.

The oxidation of 5-hydroxylmethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is a sustainable and promising method for the preparation of bio-derived aromatic polyesters. Nitrogen doped carbon material is an effective catalyst support in preparing supported nanoparticle metal catalysts in heterogeneous reactions. In this work, by pyrolysis of bio-waste carbon material, pomelo peel, under 800 °C flowing NH3, high nitrogen (up to 11.4 wt%) doped porous carbon material (NC) was facilely obtained. Pt nanoparticles (NPs) can be uniformly dispersed on NC surface and stabilized by the doped nitrogen dopant. Supported Pt NPs by NC-800 (Pt/NC-800) was proved to be an efficient catalyst in aerobic oxidation of HMF into FDCA. Control experiments show that the oxidation of 5-hydrox-ymethyl-2-furancarboxylic acid (HMFCA) to 5-formyl-2-furancarboxylic acid (FFCA) by supported Pt NPs was the key step to determine the oxidation rate of HMF to FDCA. With controlled experiment results and previous reports, a catalytic mechanism involving water, molecular O2, hydroxyl ions and Pt NPs was given and explained well of the phenomenon of high HMFCA concentration accumulation during reaction.

Mesoporous rod-like SiC has been prepared by using SBA-15 as hard template and sucrose as carbon source through a vapor-solid mechanism. The material was characterized by X-ray diffraction (XRD), high resolution transmission electronmicroscopy (HRTEM) and thermalgravimetric (TG) analysis. The obtained material exhibits different morphologies, and consists of a rod-like SiC core and amorphous silica shell which is due to the excessive silica during the reaction between silica and carbon to form SiC. The diameter of the SiC nanorods are ranged from 8 to 60 nm, and the silica shell has a thickness of about 4 nm. The silica coating SiC nanorods possess more porous structure than pure SiC and in turn make it more useful in catalytic fields.

This research focuses on high-value utilization of the lignin-derived phenol monomer and bioethanol from biorefining process. Supported-heteropolyacid is easily used as an efficient catalyst for the ethylation of phenol with bioethanol to obtain value-added products. Through adjusting the loading amount, different acidity amount and strength can be obtained, leading to the tunable selectivity to the phenol ethylation route and regioselectivity.

N-doped graphene materials with various types and quantities of N species were prepared via thermal treatment of graphene oxide in flowing NH3, and their catalytic performance was tested in aerobic selective oxidation of 5-hydroxymethyl-furfural (HMF). A full HMF conversion and nearly 100% selectivity to DFF can be obtained under relatively mild reaction conditions (6 h, 100 °C, 1 atm air pressure) with 2,2,6,6-tetramethylpiperidin-oxyl (TEMPO) as co-catalyst. The reduction degree of graphene oxide in NH3 was characterized by visible Raman spectroscopy. The amount and nature of doped nitrogen species were examined by X-ray photoelectron spectroscopy to reveal the genesis of active species by nitrogen doping. The graphitic nitrogen species doped into the graphene lattice were demonstrated to be responsible for the activation of molecular oxygen. In the selective oxidation of HMF, N-doped graphene showed a much lower apparent activation energy (ca. 13.5 kJ mol−1) compared with conventional active carbon supported metal catalysts (Ru/C, Pt/C, Pd/C, Au/C, 51–77 kJ mol−1). Based on current results and previous reports, a possible reaction pathway with the graphitic N species as active sites was proposed. This study examines the origin of the enhanced catalytic activity, which can be linked to the synergistic effect of TEMPO, N-doped graphene and molecular oxygen. This kind of synergistic effect makes the oxidation of HMF run smoothly. The present study demonstrates the potential of functionalized nitrogen-doped graphene materials as an efficient and alternative material to metal-based catalysts for organic synthetic reactions.

Compared to 5-HMF (C6H6O3), angelica lactone (C5H6O2) is a platform compound that has more potential for biomass-derived high performance bio-alkane fuel production due to a CC bond in the molecular structure, leading to a C–C coupling intermediate (C10 self-aggregation dimer) and higher C:O ratio (2.5), resulting in lower hydrogen consumption for the subsequent hydrodeoxygenation process. Biomass-derived levulinic acid was used as the only starting raw material to produce C10 branched alkanes. First, carboxyl and carbonyl functional groups of levulinic acid under catalysis via intramolecular esterification and dehydration yielded angelica lactone, which included two isomers of angelica lactone (α-angelica lactone and β-angelica lactone). Secondly, angelica lactone di/trimers would be obtained by angelica lactone self-aggregation: α-angelica lactone and β-angelica lactone connecting via C–C bond coupling. Finally, these intermediate products are selectively hydrodeoxygenated over a RANEY® catalyst to obtain C7–C10 branched alkanes. Nearly a 90% yield can be achieved under 483 K and 5 MPa H2 and the C10 branched alkane product, 3-ethyl-4-methyl heptane, accounts for 75% of the same.

Graphene oxide (GO) sheets are emerging as a new class of carbocatalyst, and also a perfect platform for molecular engineering. The hydroxyl groups on either side of GO sheets can function as anchors by employing them as scaffolds linking organometallic nodes and vanadium-oxo was homogeneously immobilized on a Schiff base modified GO support via covalent bonding. The developed VO–NH2-GO was shown to be an efficient and recyclable heterogeneous catalyst for the aerobic oxidation of 5-hydroxymethylfurfural (HMF) into maleic anhydride. Up to 95.3% yield of maleic anhydride from HMF and 62.4% from furfural were achieved under optimized reaction conditions. The immobilized vanadium oxo was identified as the active sites, while the residual oxygen-containing groups worked synergistically to adsorb HMF to maintain a high reactant concentration around the catalyst. The STY value was enhanced significantly over VO–NH2-GO, compared with homogeneous or heterogeneous traditional supported V based catalyst.

It is of vital importance to design stable and selective heterocatalysts for aqueous production of platforms from biomass-derived sugars. This paper describes a selective aqueous conversion of fructose to HMF using carbon catalysts from pulping waste sodium ligninsulfonate (SLS). The effect of carbonization atmospheres (N2 flow, static air and air flow) on the structure, porosity, compositions and acidic properties of carbon catalysts were investigated by thermogravimetry-mass spectrum analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Boehm titrations, N2 adsorption–desorption isotherms and elemental analysis. The carbonization in air flow favored the formation of more oxygen-containing functional groups and micropores, while more sulfonic groups and meso-/macro-pores were formed during carbonization in a static air atmosphere. Both oxygen- and sulfur-containing groups were acid sites, and their total amount was the largest when carbonized in air flow, followed by static air and N2 flow. The positive correlation between the acid amounts and fructose conversion of carbon catalysts clearly demonstrated the catalytic effect of the acid sites. The steric hindrance of micropores in carbon catalysts restricted the formation of humins and promoted the HMF selectivity compared with meso-/macro-pores.

An efficient strategy is developed for chemical recycling of cured epoxy resin (CEP) from its carbon fiber reinforced polymer composites (CFREP) using AlCl3/CH3COOH as the degradation system. Acetic acid swells the dense structures of CEP, facilitating the penetration of the aluminum ion catalyst into the polymer matrix. The weakly coordinating aluminum ions in CH3COOH solution selectively cleave the C–N bond while leaving the C–C, C–O (aryl alkyl ether) bonds intact. This process recovers valuable oligomers and carbon fibers from CFREP.

A series of catalysts constituted by nanoparticles of transition metal (M = Fe, Co, Ni and Mo) phosphides (TMP) dispersed on SBA-15 were synthesized by reduction of the corresponding metal phosphate precursors previously impregnated on the mesostructured support. All the samples contained a metal-loading of 20 wt% and with an initial M/P mole ratio of 1, and they were characterized by X-ray diffraction (XRD), N2 sorption, H2-TPR and transmission electron microscopy (TEM). Metal phosphide nanocatalysts were tested in a high pressure continuous flow reactor for the hydrodeoxygenation (HDO) of a methyl ester blend containing methyl oleate (C17H33-COO-CH3) as main component (70%). This mixture constitutes a convenient surrogate of triglycerides present in vegetable oils, and following catalytic hydrotreating yields mainly n-alkanes. The results of the catalytic assays indicate that Ni2P/SBA-15 catalyst presents the highest ester conversion, whereas the transformation rate is about 20% lower for MoP/SBA-15. In contrast, catalysts based on Fe and Co phosphides show a rather limited activity. Hydrocarbon distribution in the liquid product suggests that both hydrodeoxygenation and decarboxylation/decarbonylation reactions occur simultaneously over the different catalysts, although MoP/SBA-15 possess a selectivity towards hydrodeoxygenation exceeding 90%. Accordingly, the catalyst based on MoP affords the highest yield of n-octadecane, which is the preferred product in terms of carbon atom economy. Subsequently, in order to conjugate the advantages of both Ni and Mo phosphides, a series of catalysts containing variable proportions of both metals were prepared. The obtained results reveal that the mixed phosphides catalysts present a catalytic behavior intermediate between those of the monometallic phosphides. Accordingly, only marginal enhancement of the yield of n-octadecane is obtained for the catalysts with a Mo/Ni ratio of 3. Nevertheless, owing to this high selectivity for hydrodeoxygenation MoP/SBA-15 appears as a very promising catalyst for the production of advanced biofuels.

By thermal treatment in vacuum, graphite oxide prepared by Hummer’s method was exfoliated and partially reduced. This procedure imparts to the graphene oxide (GO) high reactivity with 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) as cocatalyst for selective oxidation of 5-hydroxymethylfrufural (HMF) to 2,5-diformylfuran (DFF) under certain conditions (100% HMF conversion with HMF selectivity 99.6% at 80 wt % GO loading, 1 atm air pressure). This study found that GO could function as an oxidant for anaerobic oxidation of HMF during which carboxyl groups in GO were reduced. Importantly, the partially reduced GO material could continue to activate molecular oxygen during aerobic oxidation. Further study showed that oxygen functionalities in the GO material had a crucial effect on the catalytic oxidation of HMF. By control experiments and molecular analogues tests, a plausible mechanism was proposed in which the high reactivity was attributed to the synergistic effect of the carboxylic acid groups and unpaired ...

A series of high-performance catalysts based on nickel phosphide particles supported on SBA-15 have been synthesized by temperature-programed reduction of a nickel phosphate, previously impregnated in the mesostructured silica support. In these samples the loading of the active phase varied between 10% and 20% in a Ni basis, while nominal Ni/P ratios ranged from 0.5 to 3. The formation of different active phases, Ni2P, Ni12P5 or Ni3P, depending on the P/Ni proportion was verified by X-ray diffraction (XRD). The study of these catalysts by transmission electron microscopy (TEM) and Energy-Dispersive X-ray spectroscopy (EDX) revealed that the majority of the phosphide nanoparticles present a relatively uniform diameter evenly distributed within the SBA-15 channels. All the nickel phosphide catalysts, as well as a reference Ni/SBA-15 catalyst, were tested for the hydrodeoxygenation (HDO) of methyl oleate (C17H33–COO–CH3) in a high pressure continuous flow reactor. This compound was used as a convenient surrogate of triglyceride molecules present in vegetable oils, and following catalytic hydrotreating yields mainly n-alkanes at 30 bars and temperature in the 250–340 °C range. In all cases lower contact time and reaction temperature decrease the conversion but favor the formation of C18 alkanes, which is the preferred product in terms of carbon atom economy. In addition, this study reveals that activity and selectivity are affected remarkably by the Ni/P ratio. Maximum conversion is achieved for the catalysts prepared with an initial Ni/P ratio of 1, while selectivity to C18 is larger for the catalyst with an initial Ni/P ratio of 2. These catalysts contain predominantly the Ni2P phase, which seem to be the most active for this process, although the presence of Ni12P5 in the case of the catalysts with Ni/P = 2 appears to be also positive. On the basis of the product distribution it can be concluded that both hydrodeoxygenation and decarboxylation/decarbonylation reactions occur simultaneously over the nickel phosphide catalysts, whereas decarboxylation and cracking are the prevailing processes over the Ni/SBA-15 catalyst. Owing to these high yields of long-chain paraffins, SBA-15-supported nickel phosphide catalysts can be considered as a very promising catalyst for the transformation of vegetable oils into green diesel.

Ni/γ-Al2O3, Ni/AlSBA-15 and Ni/HZSM-5 catalyst with small amount of active metal of 1 wt% Ni loading were prepared. The performance for hydrodeoxygenation upgrading of a model bio-oil was evaluated under different reaction conditions. It was found that Ni/γ-Al2O3 displays the highest anisole conversion 60% at WHSV = 81.6 h−1 and nearly 100% at WHSV = 20.4 h−1 as compared with Ni/AlSBA-15 and Ni/HZSM-5. Toluene, a premium aromatic product, could form and the maximum toluene selectivity 20% could be obtained at WHSV = 20.4 h−1 at 3 bars over Ni/HZSM-5. 10% n-hexane selectivity could be obtained over Ni/HZSM-5 at WHSV = 20.4 h−1 at 3 bars. 70% arene selectivity could be obtained at WHSV = 81.6 h−1 at 3 bars over Ni/HZSM-5.

Hydrodeoxygenation (HDO) of anisole has been often investigated in connection with biofuel production by bio-oil upgrading, because this molecule is representative of the methoxyphenyl components generated by flash pyrolysis of lignocellulose biomass. In the present work a series of Ni-containing (20 wt% loading) catalysts based on carriers as diverse as SBA-15, Al-SBA-15, γ-Al2O3, microporous carbon, TiO2 and CeO2 were selected in order to investigate the possible influence of metal–support interactions on the selectivity of anisole HDO toward aromatic products. Both, supports and catalysts were extensively characterized by N2 adsorption–desorption isotherms, X-ray diffraction (XRD), transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR) and ammonium programmed desorption (NH3-TPD). Subsequently, the catalysts were tested for the hydrodeoxygenation of anisole in a continuous flow high pressure reactor. Under low hydrogen pressure (3 bars) and moderate temperature (290–310 °C) and space velocity (20.4 and 81.6 h−1), these catalysts show a very high HDO activity that, for most of them approaches to 100%. Differences in product distribution among the catalysts are attributed not only to variations in the dispersion of the active phase, but also to the influence of the support properties in tuning its reactivity. In particular, acidity of the support is very relevant because strong acid sites may contribute the hydrogenolysis of anisole, while metallic sites will further hydrogenate intermediate compounds to yield cyclohexane. Therefore, the selective production of aromatics, from biomass derived feedstock in a biorefinery scheme can be promoted by an adequate selection of the catalysts characteristics. In this respect, a maximum yield of 64% of benzene was obtained in this study over Ni/C catalysts.

Hydrodeoxygenation (HDO) is a suitable process to eliminate the oxygen content in vegetable oils and to produce a renewable fuel with characteristics similar to petroleum derived diesel. In this investigation, ordered mesoporous materials based on SBA-15 and Al-SBA-15 were synthesized and impregnated by incipient wetness impregnation with Ni or Co nitrate, being subsequently calcined and reduced with hydrogen. All the samples were characterized by means of XRD, N2 adsorption–desorption analysis at 77 K, ICP-OES, H2-TPR and TPD-NH3. Hydrotreating of a methyl esters mixture, used as convenient surrogate of triglycerides, was studied in the present work. Catalytic tests were carried out in a fixed-bed tubular reactor at 340–300 °C and 30 bar of H2 for 6 h, obtaining n-paraffins as main products. The results revealed that the presence of aluminum in the supports favors HDO processes, specifically at low temperatures, achieving higher selectivities and yields to C18 hydrocarbons than SBA-15 based materials. Besides, acid sites promote the formation of non-linear hydrocarbons in addition to n-paraffins, which are mainly produced with pure silica based catalysts. Regarding active phases, Co proved to be more active than Ni under the reaction conditions used in this study. On the basis of these results, Co/Al-SBA-15 can be considered as a very promising catalyst for the production of biofuels in diesel range from vegetable oils with a remarkable HDO activity.

The effect of Mn doping on the adsorptive desulfurization performance of 5%Ni/ZnO adsorbents was investigated in model gasoline, with thiophene as a sulfur-containing compound, using a fixed-bed reactor. The 5%Ni/MnO-ZnO adsorbents with different levels of Mn doping were prepared using an incipient wetness impregnation method and characterized by powder X-ray diffraction (XRD). It was found that the adsorption performances of the 5%Ni/MnO-ZnO adsorbents were considerably improved after Mn doping compared with that of 5%Ni/ZnO. Moreover, the 5%NiO/MnO-ZnO adsorbents showed high desulfurization activities after regeneration. Sulfur removal by a 5%NiO/8%MnO-ZnO adsorbent after three reaction-regeneration cycles was 4% higher than that by a 5%NiO/ZnO adsorbent without Mn doping. The excellent performance of the 5%NiO/8%MnO-ZnO adsorbent in desulfurization, and its regenerability, were attributed to formation of a new compound, ZnMnO3, in the adsorbent; this compound was characterized using XRD.

The effect of zno particle size on the adsorptive desulfurization performance for ni/zno (5 wt% nio) adsorbent was investigated using thiophene as a sulfur containing compound in model gasoline with a fixed bed reactor. the ni/zno adsorbents with different zno particle sizes (8, 12, 20, 30 nm) were prepared by an impregnation method and characterized by powder x-ray diffraction (xrd), high resolution transmission electron microscopy (hrtem) and transmission electron microscopy (tem). it was found that the adsorption capacity of the ni/zno adsorbent for thiophene significantly increased with the decrease of the zno particle sizes. typically at a breakthrough sulfur level of 1 mg/l, sulfur capacity of ni/zno (8 nm) from model gasoline (500 mg/l) is much higher than that of ni/zno (30 nm) from 84 mg sulfur per gram adsorbent to nearly 0 mg sulfur per gram adsorbent. this higher desulfurization activity and sulfur capacity for ni/zno with smaller zno particle sizes could be derived from higher ni dispersion on zno and lower mass transfer limitations of sulfur to zno from ni in h-2. (c) 2012 elsevier bm. all rights reserved.

A novel hydrodeoxygenation catalytic system, Ni2P/SBA-15, has been synthesized by temperature-programmed reduction of a nickel phosphate precursor impregnated in the mesostructured silica support. The formation of this active phase was verified by X-ray diffraction, whereas the study by transmission electron microscopy revealed that the catalyst is mainly constituted of nickel phosphide particles of relatively uniform size dispersed within the SBA-15 channels. Both Ni2P/SBA-15 and a reference Ni/SBA-15 catalyst were tested for the hydrodeoxygenation of methyl oleate (C17H33–COO–CH3) in a fixed-bed continuous flow reactor. This compound was used as a convenient surrogate of triglyceride molecules present in vegetable oils that following catalytic hydrotreating yields n-alkanes as the main products. In the whole range of pressure studied (3–40 bar) and for temperatures higher than 290 °C, both systems achieve more than 80% ester conversion at 20 h–1 WHSV, although the Ni/SBA-15 catalyst presents a slightly ...

A recyclable amphiphilic catalyst, which composed of peroxotungsten anion and quaternary ammonium cation assembled in the interface of the emulsion droplets, shows high selectivity and activity in the oxidation of sulfur-containing molecules to sulfones with hydrogen peroxide in diesel under mild reaction conditions. all the sulfur-containing molecules present in diesel can be completely oxidized into sulfones with -100% selectivity of sulfones in w/o (h2o2-in-diesel) emulsion system. the sulfones can be readily separated from the diesel, and the sulfur level of the desulfurized diesel can be lowered from about 500 ppm to below 1 ppm with about 98% yield of oil. in addition, the s-containing molecules in straight-run gas oil are also readily oxidized to their corresponding products in the oav emulsion reaction medium. the s-level of oil layer of the oxidized oil was reduced to below 1 ppm from 312 ppm in the original straight-run gas oil with above 99% yield of oil. the amphiphilic catalysts serve as not only a catalyst but also an emulsifying agent to stabilize the emulsion droplets. the emulsion droplets are not only in the highly dispersed form but also behave like homogenous catalyst with high activity. the limitations due to interphase mass transport are greatly reduced in emulsion reaction medium. moreover, the emulsion catalysts can be easily separated and recycled by demulsifying. (c) 2006 elsevier b.v. all rights reserved.

The oxidation of sulfur-containing compounds (benzothiophene, dibenzothiophene, and their derivatives) in diesel was conducted in emulsion oxidative system (water in oil [w/o]) composed of diesel. 30 wt% hydrogen peroxide, and ail amphiphilic catalyst [c18h37n(ch3)(3)](4)[h2napw10o36] under mild conditions. the amphiphilic catalyst in the w/o emulsion system exhibits very high catalytic activity such that all sulfur-containing compounds in either model or actual diesel can be selectively oxidized into their corresponding sulfones using hydrogen peroxide (o/s

Catalysts assembled in emulsions are found to be potentially recoverable and efficient for a number of catalytic reactions. The catalysts composed of polyoxometalate anions and quaternary ammonium cations have been designed and synthesized according to the catalytic reactions and by optimizing the structures of cations and anions. The catalysts act essentially as surfactants, which are uniformly distributed in the interface of the emulsion droplets, and accordingly behave like homogeneous catalysts. The catalysts show remarkable selectivity and activity in the oxidation of sulfur-containing molecules to sulfones in diesel and the selective oxidation of alcohols to ketones, using H2O2 as oxidant. For an example, the catalyst demonstrated over 96% efficiency of H2O2 and ˜100% selectivity to sulfones for the selective oxidation of sulfur-containing molecules in real diesel. Moreover, the catalysts can be separated and recycled by a simple demulsification and re-emulsification.

Silica-supported binary and ternary phosphides, mop/sio2, ni2p/sio2, and ni-mo-p/sio2 have been prepared and characterized by x-ray diffraction (xrd), bet surface area, co chemisorption, transmission electron microscopy (tem), and infrared spectroscopy (ir). the hydrodesulfurization (hds) activities of dibenzothiophene (dbt) were measured and compared at 593 k and 3.0 mpa for mop/sio2, ni2p/sio2, and ni-mo-p/sio2 catalysts with different mo and ni loadings. the activities of the phosphides follow the order ni2p/sio2 > ni-mo-p/sio2 > mop/sio2. the ni sites in the ni-mo-p/sio2 catalysts play a major role in the conversion of dbt, and the activity of the catalysts increases with increasing ni content. this is different from sulfides, nitrides, and carbides, as no synergetic effect is observed between the phosphided ni and the mo atoms. the surface of these phosphide catalysts is partially sulfided forming a surface phosphosulfide phase, while the bulk structure of the phosphides is maintained in the hds reactions. (c) 2004 elsevier inc. all rights reserved.

Dibenzothiophene (DBT) is oxidized to the corresponding sulfoxide and sulfone in an emulsion system (W/O) composed of polyoxometalate anion [C(18)H(37)N(CH(3))3](5)[PV(2)Mo(10)O(40)] as both the surfactant and catalyst, using molecular oxygen as the oxidant and aldehyde as the sacrificial agent under mild conditions.

A [(C(18)H(37))(2)N(+)(CH(3))(2)](3)[PW(12)O(40)] catalyst, assembled in an emulsion in diesel, can selectively oxidize the sulfur-containing molecules present in diesel into their corresponding sulfones by using H(2)O(2) as the oxidant under mild conditions. The sulfones can be readily separated from the diesel using an extractant, and the sulfur level of the desulfurized diesel can be lowered from about 500 ppm to 0.1 ppm without changing the properties of the diesel. The catalyst demonstrates high performance (>/=96 % efficiency of H(2)O(2), is easily recycled, and approximately 100 % selectivity to sulfones). Metastable emulsion droplets (water in oil) act like a homogeneous catalyst and are formed when the catalyst (as the surfactant) and H(2)O(2) (30 %) are mixed in the diesel. However, the catalyst can be separated from the diesel after demulsification.