Hydrogen-Free Deoxygenation of Bio-Oil Model Compounds over Sulfur-Free Polymer Supported Catalysts

Thermodynamic analysis of aqueous phase reforming of three model compounds in bio-oil for hydrogen production

Exploring the catalytic conversion of aromatic model compounds of coal pyrolysis over Ca(OH)2

Hydrofining of oxygen-containing compounds of bio-oil allows efficient use of the final product as a liquid fuel from biomass. Deoxygenation is considered to be one of the most perspective ways to modernize bio-oil. Generally, deoxygenation is carried out under fairly strict conditions in the presence of hydrogen in a medium of high-boiling hydrocarbons. This paper describes a new approach to deoxygenation of model compounds of bio-oil using supercritical liquids as a solvent and hydrogen donor. The possibility of using a complex solvent consisting of non-polar n-hexane with a low critical point (Tc = 234.5 °C, Pc = 3.02 MPa) and propanol-2 used as a hydrogen donor is evaluated. Experiments have shown that in the presence of 20 vol. % propanol-2 in n-hexane a maximum (99%) conversion of model bio-oil compounds with the formation of phenols with a yield of up to 95% is observed.

Density functional theory calculations were employed to investigate the nucleation and growth of small palladium clusters, up to Pd9, into a microcavity of the porous hyper-cross-linked polystyrene (HPS). The geometries and the electronic structures of the palladium clusters inside the HPS cavity, following the one-by-one atom addition, are affected by a counterbalance between the Pd–phenyl (Pd−Φ) and Pd–Pd interactions. The analysis performed on energetics, cavity distortions, and cluster geometries indeed suggest that the cluster growth is dominated by the Pd−Φ interactions up to the formation of Pd4 aggregates, whereas the metal–metal interactions actually rule the growth of the larger clusters. The elasticity of the hyper-cross-linked polystyrene matrix also plays an important role in the cluster development processes.

Insight into enhanced activation of permanganate under simulated solar irradiation: Rapid formation of manganese species

A new type of Ru-containing magnetically recoverable catalyst based on a polymer matrix of hypercrosslinked polystyrene (HPS) for the reaction of the hydrogenolysis of microcrystalline cellulose to ethylene and propylene glycol (EG and PG) is proposed. The catalyst is synthesized sequentially in two stages. At the first stage, by means of thermal decomposition of iron (III) salts in the presence of polyols, magnetite particles (Fe3O4) are formed in the pores of the HPS. At the second stage, Ru-containing nanoparticles of the active phase of the catalyst are synthesized on the surface of Fe3O4/HPS. Samples of the original HPS, Fe3O4/HPS and Ru-Fe3O4/HPS were characterized using various physicochemical methods. In particular, it was shown that the synthesized samples of catalysts have a high specific surface area (450 - 750 m2/g, depending on the magnetite content), retain the micro-mesoporous nature of the original polymer, and have a high saturation magnetization (4.0 ± 0.5 emu /g), which makes them easy to separate from the reaction mass by an external magnetic field. According to the results of transmission electron microscopy (TEM), the average diameter of the nanoparticles of the active phase Ru was 2.0 ± 0.5 nm. The hydrogenolysis of cellulose to glycols was carried out under the following conditions: 255 °C; 60 bar H2; 55 min; 0.3 g of cellulose; 0.07 g of catalyst 3% Ru-Fe3O4/HPS; 30 ml of H2O; 0.07 g of Ca(OH)2. Under these conditions, the selectivities for EG and PG were 22.6 % and 20.0 %, respectively. The degree of cellulose conversion reaches 100 %. The catalyst showed good stability under hydrothermal reaction conditions, is easily separated from the reaction mass by an external magnetic field, and can be used in the processes of cellulose-containing biomass conversion.

Upgrading of liquid fuel from the vacuum pyrolysis of biomass over the Mo–Ni/γ-Al2O3 catalysts

Studies of the processes of the hydrolytic oxidation of disaccharides are the first step towards the development of technologies for the direct conversion of plant polysaccharides, primarily cellulose, into aldonic and aldaric acids, which are widely used in chemical synthesis and various industries. In this study, heterogeneous catalysts based on a porous matrix of hypercrosslinked polystyrene (HPS) and noble metals (Pt, Au, Ru, and Pd) were proposed for the hydrolytic oxidation of cellobiose to gluconic and glucaric acids. The catalysts were characterized using low-temperature nitrogen adsorption, hydrogen chemisorption, electron microscopy, and other methods. In particular, it was shown that the Pt-containing catalyst contained, on average, six times more active centers on the surface, which made it more promising for use in this reaction. At a temperature of 145 °C, an O2 pressure of 5 bars, and a substrate/catalyst weight ratio of 4/1, the yields of gluconic and glucaric acids reached 21.6 and 63.4%, respectively. Based on the data obtained, the mathematical model of the cellobiose hydrolytic oxidation kinetics in the presence of 3% Pt/HPS MN270 was developed, and the parameter estimation was carried out. The formal description of the kinetics of cellobiose hydrolytic oxidation was obtained.

In this work, a polymer heterogeneous Pt-containing catalyst based on a mesoporous matrix of hypercrosslinked polystyrene (HPS) is proposed for the process of hydrolytic oxidation of cellobiose. Studies of the processes of hydrolytic oxidation of disaccharides are the first step towards the development of technologies for the direct conversion of plant polysaccharides, primarily cellulose, into aldonic and aldaric acids, which are widely used in chemical synthesis and various industries. It was shown that the use of Pt-containing catalytic systems based on a polymer matrix of hypercrosslinked polystyrene in the process of hydrolytic oxidation of cellobiose to gluconic and glucaric acids is promising. The yield of gluconic and glucaric acids reaches 21.6 and 63.4%, respectively.

Catalytic properties of Ru nanoparticles introduced in a matrix of hypercrosslinked polystyrene toward the low-temperature oxidation of d-glucose

Molecular composition of oxygenated compounds in fast pyrolysis bio-oil and its supercritical fluid extracts

A novel Ru@G-CS composite, in which 1–2 layered N-doped graphene encapsulated nano-sized Ru (2.5 ± 1.0 nm) particles, was fabricated on carbon sheets (CS) via the direct pyrolysis of mixed glucose, melamine and RuCl3. And Ru@G-CS-700 (pyrolysis at 700 °C) is highly active, selective and stable for the hydrogenation of model compounds (such as phenols, furfurals and aromatics) in bio-oil in water.

Deep eutectic solvent for lignocellulosic biomass fractionation and the subsequent conversion to bio-based products – A review

The kinetics of hydrodeoxygenation (HDO) reaction in literature are mostly reported for single model compounds in bio-oil. However, these kinetic models may become invalid in the real bio-oil environment where other model compounds are present. This study investigates the effect of acetic acid, which is a major compound in bio-oil, on the liquid-phase HDO reaction kinetics of vanillin (VL). A synthesized bimetallic catalyst (PdRh/Al2O3) was utilized in a batch reactor at 308–328 K, 1–4 MPa H2 gas partial pressure (PH), 263–526 mM initial VL concentration (CVL0), and 1.9–4.6 kg/m3 catalyst loading with ethyl acetate as the reaction solvent. N2 adsorption–desorption, scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), CO chemisorption, and mercury porosimetry methods were used to determine the physicochemical properties of the catalyst. Transport limitations in the system were ruled out via the Madon–Boudart test, Weisz–Prater criterion, agitation, and particle size test. ...

Effects of Gas Flow Rate, Inlet Concentration and Temperature on Biofiltration of Volatile Organic Compounds in a Peat-Packed Biofilter