Hydrodeoxygenation Of Vanillin Research Articles

Pd Nanoparticles Supported on Cellulose as a Catalyst for Vanillin Conversion in Aqueous Media

Palladium nanoparticles were first anchored on modified biopolymer as an efficient catalyst for a biofuel upgrade. Fluorinated compounds was grafted onto cellulose to obtain amphiphilic supports for on water reactions. Pd catalyst was prepared by straightforward deposition of metal nanoparticles on modified cellulose. The catalyst exhibited excellent catalytic activity and selectivity in hydrodeoxygenation of vanillin (a typical model compound of lignin) to 2-methoxy-4-methylphenol under atmospheric hydrogen pressure in neat water without any other additives under mild conditions.

Cu–Pd bimetallic nanoalloy anchored on a N-rich porous organic polymer for high-performance hydrodeoxygenation of biomass-derived vanillin

A N-rich porous organic polymer-anchored bimetallic Cu–Pd nanoalloy exhibited superior catalytic activity with improved stability for biomass-derived selective hydrodeoxygenation of vanillin.

Palladium Nanoparticles Encaged in a Nitrogen‐Rich Porous Organic Polymer: Constructing a Promising Robust Nanoarchitecture for Catalytic Biofuel Upgrading

AbstractRobust nanoarchitectures based on surfactant‐free ultrafine Pd nanoparticles (NPs) (2.7–8.2±0.5 nm) have been developed by using the incipient wetness impregnation method with subsequent reduction of PdII species encaged in the 1,3,5‐triazine‐functionalized nitrogen‐rich porous organic polymer (POP) by employing NaBH4, HCHO, and H2 reduction routes. The Pd‐POP materials prepared by the three different synthetic methods consist of virtually identical chemical compositions but have different physical and texture properties. Strong metal–support interactions, the nanoconfinement effect of POP, and the homogeneous distribution of Pd NPs have been investigated by performing 13C cross‐polarization (CP) solid‐state magic angle spinning (MAS) NMR, FTIR, and X‐ray photoelectron spectroscopy (XPS), along with wide‐angle powder XRD, N2 physisorption, high‐resolution (HR)‐TEM, high angle annular dark field scanning transmission electron microscopy (HAADF‐STEM), and energy‐dispersive X‐ray (EDX) mapping spectroscopic studies. The resulting Pd‐POP based materials exhibit highly efficient catalytic performance with superior stability in promoting biomass refining (hydrodeoxygenation of vanillin, a typical compound of lignin‐derived bio‐oil). Outstanding catalytic performance (≈98 % conversion of vanillin with exclusive selectivity for hydrogenolysis product 2‐methoxy‐4‐methylphenol) has been achieved over the newly designed Pd‐POP catalyst under the optimized reaction conditions (140 °C, 10 bar H2 pressure), affording a turnover frequency (TOF) value of 8.51 h−1 and no significant drop in catalytic activity with desired product selectivity has been noticed for ten successive catalytic cycles, demonstrating the excellent stability and reproducibility of this catalyst system. A size‐ and location‐dependent catalytic performance for the Pd NPs with small size (1.31±0.36 and 2.71±0.25 nm) has been investigated in vanillin hydrodeoxygenation reaction with our newly designed Pd‐POP catalysts. The presence of well‐dispersed electron‐rich metallic Pd sites and highly rigid cross‐linked amine‐functionalized POP framework with high surface area is thought to be responsible for the high catalytic activity and improvement in catalyst stability.

Palladium Nanoparticles Supported on a Metal–Organic Framework‐Partially Reduced Graphene Oxide Hybrid for the Catalytic Hydrodeoxygenation of Vanillin as a Model for Biofuel Upgrade Reactions

AbstractIn this work we report a new strategy to enhance the catalytic activity and selectivity in heterogeneous catalysis by using a hybrid support that consists of metal–organic framework (MOF) crystals and partially reduced graphene oxide (PRGO) nanosheets to disperse metal nanoparticle catalysts efficiently. We report the development of a Pd nanocatalyst incorporated within a 3 D hierarchical nanocomposite that consists of a Ce‐based MOF wrapped with thin PRGO nanosheets, Pd/PRGO/Ce‐MOF, as a heterogeneous tandem catalyst for the hydrodeoxygenation of vanillin, a common component in lignin‐derived bio‐oil, under mild reaction conditions. Our results demonstrate that the PRGO/Ce‐MOF hybrid scaffold is an excellent support for Pd nanoparticles for the transformation of vanillin into 2‐methoxy‐4‐methyl phenol, an important high‐value phenol compound that can be used directly in the chemical and pharmaceutical industries. The high catalytic performance of the Pd/PRGO/Ce‐MOF catalyst is attributed to the unique characteristics of the incorporation of the PRGO support that leads not only to a stable and uniform dispersion of the Pd nanoparticles but also to the presence of acidic active sites that promote the hydrogenolysis reaction.

Mild-temperature hydrodeoxygenation of vanillin over porous nitrogen-doped carbon black supported nickel nanoparticles

N-doped carbon black (NCB) supported Ni NPs exhibited higher activity than most Ni-based catalysts for selective HDO of vanillin at mild conditions, ascribing to higher reducibility, lower oxidation state of Ni NPs and enhanced spillover hydrogen of Ni to NCB.

Co embedded within biomass-derived mesoporous N-doped carbon as an acid-resistant and chemoselective catalyst for transfer hydrodeoxygenation of biomass with formic acid

Biomass-derived acid-resistant Co@NC is used as a bifunctional catalyst for biomass-derived FA dehydrogenation and biomass-derived vanillin hydrodeoxygenation.

One-pot catalytic reaction to produce high-carbon-number dimeric deoxygenated hydrocarbons from lignin-derived monophenyl vanillin using Al2O3-cogelled Ru nanoparticles

Al2O3-cogelled Ru nanoparticle (Ru@Al) catalyst was prepared by a one-pot in-situ alumina gelation method using a PVP-stabilized Ru colloid solution. The Ru@Al catalyst exhibited excellent catalytic activity during the liquid-phase hydrodeoxygenation of vanillin, demonstrating 100% conversion, as well as significantly higher yields of fully deoxygenated compounds compared to other conventional alumina-supported Ru catalysts. We also observed better selectivity to deoxygenated dimers with the Ru@Al catalyst. The improved catalytic selectivity was attributed to the hypothesized three-dimensional structures of Al2O3 surrounding the Ru nanoparticles, which improved the two-step reaction, containing the dimerization of the phenolic compounds and the hydrodeoxygenation of phenolic dimers to produce deoxygenated high-carbon-number hydrocarbons.

Visible light mediated upgrading of biomass to biofuel

Heterogenized bimetallic Ag–Pd nanoparticles on graphitic carbon nitride (AgPd@g-C3N4) promote upgrading of biofuel via hydrodeoxygenation of vanillin under visible light irradiation using formic acid as a hydrogen source.

Synergetic catalysis of palladium nanoparticles encaged within amine-functionalized UiO-66 in the hydrodeoxygenation of vanillin in water

Ultrasmall palladium nanoparticles (1.5–2.5 nm) encapsulated within the highly porous and hydrothermally stable amine-functionalized metal–organic framework UiO-66 exhibit excellent catalytic activity for the selective conversion of vanillin to 2-methoxy-4-methylphenol.

Surfactant-free Pd nanoparticles immobilized to a metal-organic framework with size- and location-dependent catalytic selectivity.

Surfactant-free Pd nanoparticles, immobilized to a metal-organic framework (MIL-101), have been used for the first time as highly active and durable catalysts in water for biomass refining (hydrodeoxygenation of vanillin, a typical compound of lignin) with metal nanoparticle size- and location-dependent catalytic activity and selectivity.

Palladium nanoparticles incorporated within sulfonic acid-functionalized MIL-101(Cr) for efficient catalytic conversion of vanillin

The developed Pd/SO3H-MIL-101(Cr) catalyst exhibits novel synergy in hydrodeoxygenation of vanillin at low H2 pressure under mild conditions.

Highly dispersed molybdenum carbide nanoparticles supported on activated carbon as an efficient catalyst for the hydrodeoxygenation of vanillin

Characterized by XRD and TEM, highly dispersed molybdenum carbide (Mo2C) nanoparticles with a diameter of 1–4 nm were effectively synthesized on activated carbon at 700 °C.

Hydrodeoxygenation of vanillin over carbon nanotube-supported Ru catalysts assembled at the interfaces of emulsion droplets

Carbon nanotube supported ruthenium catalysts, assembled at the water/oil interfaces, show excellent activity and selectivity for the hydrodeoxygenation of the bio-oil model compound of vanillin under mild conditions (1MPa, 150°C). Based on a direct fluorescence image, the Ru/CNT catalysts are mainly distributed on the surface of the emulsion droplets, forming a Pickering emulsion. Simultaneous reaction and separation of the products are achieved in the constructed emulsions, which have great potential in the simplifications of the isolation and purification stages for bio-oil refining.

Hydrodeoxygenation of vanillin as a bio-oil model over carbonaceous microspheres-supported Pd catalysts in the aqueous phase and Pickering emulsions

Amphiphilic carbonaceous microspheres-supported Pd catalysts are effective in hydrodeoxygenation of vanillin in aqueous phase and Pickering emulsions.

Au/CNTs catalyst for highly selective hydrodeoxygenation of vanillin at the water/oil interface

Au/CNTs assembled at the interfaces of emulsion droplets exhibits good catalytic activity and 100% selectivity for the hydrodeoxygenation of vanillin to p-creosol.

Modelling of experimental vanillin hydrodeoxygenation reactions in water/oil emulsions. Effects of mass transport

We have studied the coupling of mass transport and chemical reaction rates in a biphasic emulsion system. The emulsion is stabilized by the presence of solid nanoparticles that, in addition, act as a catalyst for the reaction. These solid nanoparticles are composed of carbon nanotubes (CNTs) attached to SiO2 nanoparticles. Both components, CNTs and silica, can be selectively impregnated by a catalytic active phase (e.g. Pd) forming the so-called nanohybrids. We have studied the application of the catalytic nanohybrids in emulsions of type (w/o), during the reaction of hydrodeoxygenation of vanillin (4-hydroxy-3-methoxy-benzaldehyde). This is a model reaction that occurs in the aqueous side of the interface of the emulsion. The main target for this work is to analyze the impact of mass transport of the main compounds between the aqueous and organic phases on the global performance of the reaction.

Superhydrophilic mesoporous sulfonated melamine–formaldehyde resin supported palladium nanoparticles as an efficient catalyst for biofuel upgrade

Mesoporous sulfonated melamine–formaldehyde resin (MSMF) has been successfully synthesized from the self-assembly of a copolymer surfactant (F127) with a mixture of melamine, formaldehyde and NaHSO3 in an aqueous solution. After removal of the copolymer surfactant (F127) by ethanol extraction, the MSMF exhibits uniform mesopore sizes centered at 10.2 nm. The contact angle (0°) of water on the sample shows that the MSMF is superhydrophilic. After impregnating with a Pd species, a MSMF supported Pd catalyst (Pd/MSMF) is obtained, which shows high activity and excellent recyclability in an important model reaction for biofuel upgrade (hydrodeoxygenation of vanillin), compared with a conventional carbon supported Pd catalyst (Pd/C). The superior catalytic properties of the Pd/MSMF catalyst should be potentially important for biofuel upgrades in the future.

Synthesis of Palladium Nanoparticles Supported on Mesoporous N-Doped Carbon and Their Catalytic Ability for Biofuel Upgrade

We report a catalyst made of Pd nanoparticles (NPs) supported on mesoporous N-doped carbon, Pd@CN(0132), which was shown to be highly active in promoting biomass refining. The use of a task-specific ionic liquid (3-methyl-1-butylpyridine dicyanamide) as a precursor and silica NPs as a hard template afforded a high-nitrogen-content (12 wt %) mesoporous carbon material that showed high activity in stabilizing Pd NPs. The resulting Pd@CN(0.132) catalyst showed very high catalytic activity in hydrodeoxygenation of vanillin (a typical model compound of lignin) at low H(2) pressure under mild conditions in aqueous media. Excellent catalytic results (100% conversion of vanillin and 100% selectivity for 2-methoxy-4-methylphenol) were achieved, and no loss of catalytic activity was observed after six recycles.

Novel Solid Nanohybrids that Stabilize Oil/Water Emulsions and Catalyze Reactions at the Interface

AbstractA novel system has been developed to catalyze reactions at the oil/water interface of a biphasic liquid system. Stabilization of emulsions was accomplished through the use of nanohybrids composed of hydrophilic oxide particles and hydrophobic Single-Walled Carbon Nanotubes (SWNT), generated in the CoMoCAT process. These nanohybrids are inherently amphiphilic, and tend to adsorb at the interface of a biphasic water/oil liquid system. When enough energy is added to the system, these particles stabilize emulsions by suppressing the coalescence of the droplets and increasing the viscoelastic or pseudoplastic character of the liquid film between droplets. , Depending on contact angle of the particles at the liquid-liquid interface it was possible to stabilize water-in-oil or oil-in-water emulsions. The resulting emulsions are remarkably stable against coalescence and sedimentation, and can be easily separated by filtration or centrifugation, which make them suitable for applications in interfacial catalytic processes in which the catalyst can be easily recovered after reaction. Catalytic activity was imparted by transition metal clusters supported onto the nanohybrids. These metals selectively catalyze reactions at the Oil/Water interface. The proof-of-concept of the biphasic hydrogenation and condensation catalysis was obtained with three reactions of interest in biorefining. The first example was the hydrodeoxygenation of vanillin (4-hydroxy-3-methoxybenzaldehyde). The second example was the conversion of molecules that were exclusively soluble in the aqueous or the organic phase, like glutaraldehyde (water phase) and octanal (oil phase). In the third example we explored a tandem reaction sequence in which Pd-catalyzed hydrogenation was paired with a preceding Aldol-condensation of 5- methylfurfural and acetone. It was demonstrated that with these nanohybrids it is possible to selectively accomplish hydrodeoxygenation and condensation reactions at the water/oil interface of a biphasic system, followed by migration of the products to the oil phase. This contribution provides a proof-of-concept for a promising catalytic system with many potential applications in the liquid phase, such as bio-oil upgrading, production of specialty chemicals, and pharmaceutical applications in which selective reaction and product separations, based on water solubility can be desirable.