Oxidation Of Acetic Acid Research Articles

Electrochemical C(sp3)−H Functionalization Using Acetic Acid as a Hydrogen Atom Transfer Reagent

AbstractIn this study, we developed a novel electrochemical protocol that enables the functionalization of inherently inert C(sp3)−H bonds. In this protocol, one‐electron oxidation of acetic acid was used to successfully generate methyl radical, which cleaves the benzylic C(sp3)−H bonds of the substrates via a hydrogen atom transfer (HAT) process, and further reaction with the formed species yields the targeted C(sp3)−H functionalized products. To the best of our knowledge, this is the first example of the use of acetic acid in a HAT process. Notably the reaction has environment‐friendly and fine atom economy nature: the reaction is driven by the electrochemical conditions in the absence of expensive or hazardous reagents, producing only gaseous small molecules, hydrogen, carbon dioxide, and methane, as side products.

Electrosynthesis of peracetic acid using in-situ generated H2O2 enabled by carbon-based bifunctional electrodes

Electrosynthesis of peracetic acid (PAA) using in-situ generated H2O2 is a sustainable route to bypass the complexity and hazards of current industrial production routes of PAA. However, efficient electrochemical operation requires advancements in both electrocatalytic H2O2 production and the subsequent oxidation of acetic acid. Herein, we report a bifunctional carbon electrode for PAA electrosynthesis, which features metal-free carbon catalysts structured on a hierarchical array-like graphene substrate. With such a three-dimensional architecture to maximise active site utilisation and enhance mass transfer, this carbon electrode exhibits acidic H2O2 production performance comparable to metal-based counterparts. Moreover, the same electrode activates OH· from H2O2 by virtue of its surface functional group, facilitating strong oxidation of acetic acid to PAA. In a flow electrolyser that couples H2O2 production and acetic acid oxidation, the bifunctional electrode achieved continuous production of industrially relevant concentrations of PAA at high rates and low energy consumption. Our work highlights the critical role of electrode design for the decentralised synthesis of PAA, providing new insights for the electrification of the chemical industry towards a sustainable future.

Investigating the Effect of Alkali Metal Cations on Kolbe Electrolysis

Carboxylic acids, a major fraction of pyrolysis oil can be transformed electrochemically in alkanes and alcohols by Kolbe and Hofer Moest reaction. The selectivity of electrochemical decarboxylation depends on various factors, i.e. electrode material and reaction conditions (supporting electrolyte, pH and current densities) which are well explained in the literature1–3. Alkali metal cations (Li+, Na+, K+, Cs+) are widely considered inert,4 nevertheless in recent studies, a significant influence on different electrochemical reactions such as methanol5,6, ethanol7, and formic acid8 oxidation is reported. It is assumed that oxygenated species present on the electrode surface form (strong/weak) non-covalent interaction with the alkali metal cations.In this work, we studied the electrochemical oxidation of acetic acid (Kolbe electrolysis) and explored the influence of monovalent alkali metal cations (Li+, Na+, K+ and Cs+). It is observed that the product distribution and overall electrochemical activity are influenced by the presence of cations with K+ being most suitable for Kolbe electrolysis (order of activity Li+<Na+<K+~Cs+). The trend was observed irrespectively of the electrolyte conditions throughout the entire pH range at low current densities (25 mA/cm2), i.e. at pH 3 where OER is dominating, pH 5 where OER transitioned to Kolbe electrolysis and pH 9 where Hofer Moest reaction occurs. With increasing current densities (>50 mA/cm2), the influence of cations on electrooxidation diminishes showing the limitations of the effect of non-covalent interactions.To confirm the surface coverage and transition of OER to Kolbe reaction with increasing potential, we probed reaction selectivity in the inflection zone potential regime by means of RRDE. The analysis confirmed that the OER is suppressed completely in the presence of K+ cations after reaching potentials of ~2.5VRHE (inflection zone), while for Li+, OER still proceeds as confirmed by the ORR reaction at the ring electrode. Because surface coverage reflects the high activity of Kolbe electrolysis, we confirmed that the smaller cations interfere more strongly with the electrode surface adsorbed oxygenates due to strong non-covalent interaction and thus affecting the reaction. References F. J. Holzhäuser, J. B. Mensah, and R. Palkovits, Green Chem., 22, 286–301 (2020).C. Stang and F. Harnisch, ChemSusChem, 9, 50–60 (2016).T. Ashraf, A. P. Rodriguez, B. Mei, and G. Mul, Faraday Discuss. (2023)H. J. Schäfer, in Comprehensive Organic Synthesis, B. M. Trost and I. Fleming, Editors, p. 633–658, Pergamon, Oxford (1991)K. Silambarasan, J. Joseph, and S. Mayavan, Applied Surface Science, 489, 149–153 (2019).D. Strmcnik et al., Nature Chem, 1, 466–472 (2009).C. Han et al., ACS Appl. Mater. Interfaces, 14, 5318–5327 (2022).B. A. F. Previdello, E. G. Machado, and H. Varela, RSC Advances, 4, 15271–15275 (2014). Figure 1

Experimental and kinetic modeling study of acetic acid oxidation and hydrolysis in supercritical water

The oxidation and hydrolysis of 0.11–0.14 M acetic acid in supercritical water (SCW) have been investigated at temperatures of 773–873 K and a pressure of 25.0 MPa in a flow reactor. CO and CO2 were the main products at oxygen-rich conditions. For hydrolysis experiments, CH4 and CO2 were produced in nearly equal amounts while the yield of CO was negligibly small. A detailed chemical kinetic model was developed by revising the kinetic parameters of key elementary reactions. The model performance was evaluated by comparison to the present data as well as data from literature. The model predicted the kinetic behavior of acetic acid oxidation fairly well, despite of slight underprediction of CO and overprediction of CH4. It also reproduced satisfactorily the species concentrations during acetic acid hydrolysis at high temperatures. Based on the model, kinetic analyses were further conducted to identify important elementary steps and to infer reaction mechanisms.

Comparison on the formation and toxicity for chlorinated products during the oxidation of acetic acid (CH3COOH) by three widely used advanced oxidation processes (AOPs) at the presence of [formula omitted]

As a technology for industrial wastewater advanced treatment, there is a lack of relevant information the impacts of the treated effluents by advanced oxidation processes (AOPs) on ecological environment. Therefore, this study mainly compared the differences of the formation types and concentrations of chlorinated organic products（COPs）and active inorganic chlorine species (AICS) and toxicity changes in the oxidation of CH3COOH by three commonly used AOPs technologies as Fenton, ozone and electrochemical advanced oxidation process (EAOP) with the addition of Cl−. The results illustrate that in the EAOP process, trichloromethane (TCM) and Chloroacetic acids (CAAs) were the main COPs in the oxidation of CH3COOH by EAOP at 120 min. CCl4 was major COPs for the Fenton and ozone oxidation of CH3COOH, respectively. Through the algae growth inhibition experiment and the toxicity evaluation by using ECOTOX toxicity database, the toxicity of EAOP oxidation of CH3COOH to algae and fish were much higher than those from Fenton and ozone oxidation as the highest formation concentrations of inorganic by-products. Considering the toxic effects on the environment, when choosing the AOPs for the further treatment of wastewater containing Cl−, try to avoid the use of EAOP technology, and it is better to choose Fenton and ozone oxidation.

Eu3+:Y2Ti2O7 nanomaterials as efficient photocatalysts used for hydrogen and biogas production toward a sustainable environment

The main focus of this research is on energy production by clean photocatalytic technology. By using the sol–gel process, yttrium titanate nano‐photocatalysts modified with europium (x mol. Eu3+:Y2Ti2O7) have been created and used to produce photocatalytic biogas and hydrogen using acetic acid. X‐ray powder diffraction (XRD) confirms the formation of cubic Y2Ti2O7 phase. Microscopic study has indicated that Eu doping improved the shape, size, and dispersity of Y2Ti2O7 photocatalyst. Different crystal defects, including oxygen vacancies (OVs) and Ti3+ species, are demonstrated by X‐ray photoelectron spectroscopy (XPS) studies. Compared with pure Y2Ti2O7, 0.03 mol. Eu3+:Y2Ti2O7 has the highest proportion of lattice defects. The band gap energies have increased as a result of doping on Y2Ti2O7 size. Urbach energy calculations confirm that Eu3+:Y2Ti2O7 nano‐photocatalyst has the highest degree of distortion. The photoluminescence (PL) measurements have shown that 0.03 mol. Eu3+ dopant can effectively separate the active charge carriers. Electron spin resonance proved the progressive increase of defect states (OV and Ti3+) by doping, which promoted the photocatalytic activity of the nano‐photocatalyst. These photocatalysts have generated biogas and hydrogen gas via photocatalytic oxidation of acetic acid under inert conditions. The maximum photocatalytic activity for the generation of biogas and hydrogen is found in 0.03 mol. Eu3+:Y2Ti2O7. The maximum photocatalytic activity of 0.03 mol. Eu3+:Y2Ti2O7 is correlated with higher lattice defects (OV, Ti3+) and reduced charge carrier recombination. The proposed photocatalytic mechanism has been discussed. According to the findings, Eu3+:Y2Ti2O7 nano‐photocatalyst is a promising nanomaterial for the generation of energy.

Co-partial oxidation of acetic acid, methanol, and ethanol in an integrated porous media with efficient heat recirculation: Green hydrogen production and its expansion method

Green energy from biomass contributed to substituting the traditional fossil fuels and environmental protection. To explore the hydrogen production from bioethanol with the industrial by-products, a porous media burner integrated with a heat-recirculating tube was designed to realize the efficient vaporization of ethanol. Then the partial oxidation characteristics of ethanol were investigated with the acetic acid and methanol addition at different operating conditions. The results indicated that the acetic acid and methanol addition inhibited hydrogen production but promoted methane production. Compared with pure ethanol, the heating values of syngas were decreased by 3.41 and 0.64 MJ/Nm3 with the acetic acid or methanol content of 20%. The highest yields of hydrogen and carbon monoxide were achieved at 43.94% and 66.45% respectively when the ratio of acetic acid content to methanol was 5:15. Nevertheless, blended fuels achieved more syngas production at higher equivalence ratios and velocities. The hydrogen concentration of the blended fuel reached the maximum of 21%, exceeding that of pure ethanol by 1.6% when the velocity was 22 cm/s. The corresponding results provided a theoretical reference for the industrial application of bioethanol.

Evaluation of Red Wine Acidification Using an E-Nose System with Venturi Tool Sampling.

The quality of wine is checked both during the production process and upon consumption. Therefore, manual wine-tasting work is still valuable. Due to the nature of wine, many volatile components are released, and it is therefore difficult to determine which elements need to be controlled. Acetic acid is one of the substances found in wine and is a crucial substance for wine quality. Gas sensor systems may be a potential alternative for manual wine tasting. In this work, we have developed a TGS2620 gas sensor module to analyze acetic acid levels in red wine. The gas sensor module was refined according to the Venturi effect along with signal slope analysis, providing promising results. The example included in this paper demonstrates that there is a direct relationship between the slope of the MOS gas sensor response and the acetic acid concentration. This relationship is useful to evaluate the ethanol oxidation in acetic acid in red wine during its production process.

Regulating effects of Fe/C materials on thermophilic anaerobic digestion of kitchen waste: Digestive performances and methanogenic metabolism pathways

This study aimed to evaluate the effects of typical exogenous materials (Fe and C) addition on the performances of kitchen waste thermophilic (55 °C) anaerobic digestion in semi-continuous system. The expression of key enzymes in methanogenesis were demonstrated by microbiological approach, and the regulating effectsf Fe and C addition on methanogenic metabolism pathway were specially explored. Four anaerobic digestion systems (TAD, TAD + Fe, TAD + C and TAD + Fe + C) were carried out, and the running period lasted for 120 days, which was divided into four stages according to organic loading rates (OLRs) from 1.05 to 4.22 gVS/L/day. From this study, C addition improved soluble polysaccharide (sPolysaccharide), soluble protein (sProtein), soluble total organic carbon (sTOC) concentrations and hydrolase (amylase, protease and lipase) activities, while Fe addition facilitated the subsequent degradation of volatile fatty acids (VFAs). As a result, the average methane yields were promoted from 478.0 (TAD) to 487 (TAD + Fe), 597 (TAD + C) and 647.3 mL/gVS/day (TAD + Fe + C), respectively. For microbial communities, C addition promoted the relative abundances of hydrolytic bacteria (Defluviitoga), while Fe addition realized the directional enrichment of Methanothermobacter, and improved hydrogenotrophic methanogenesis ratios from 30.81 % (TAD) to 52.27 % (TAD + Fe) and 64.40 % (TAD + Fe + C). According to the expression of key enzymes in methanogenic metabolism pathways, Fe addition enhanced the syntrophic acetic acid oxidation and hydrogenotrophic methanogenesis pathway, realizing the conversion of dominated methanogenic metabolism pathway from aceticlastic methanogenesis to hydrogenotrophic methanogenesis. This study is of great significance to exposit the behaviors of conductive materials during thermophilic digestion of kitchen waste.

Study on the Effect of Electrolyte pH during Kolbe Electrolysis of Acetic Acid on Pt Anodes

AbstractKolbe already discovered in 1849 that electrochemical oxidative decarboxylation of carboxylic acids is feasible and leads to formation of alkanes and CO2, via alkyl radical intermediates. We now show for Pt electrodes that Kolbe electrolysis of acetic acid is favored in electrolytes with a pH similar to, or larger than the pKa of acetic acid, suppressing the formation of O2. However extended duration of electrolysis of acetate at basic pH results in loss of Faradaic efficiency to ethane, compensated by the formation of methanol. This change in selectivity is likely caused by the dissolution of CO2 near the electrode‐electrolyte interface, resulting in enlarged concentration of bicarbonate/carbonate. On the positively polarized, and oxidized Pt surface, these anions seem to inhibit homocoupling of methyl radicals to ethane. These results demonstrate that reaction selectivity in acetic acid (acetate) oxidation using oxidized Pt electrodes is determined by the pH and the anionic composition of the electrolyte.

The Influence of Metal-Doped Graphitic Carbon Nitride on Photocatalytic Conversion of Acetic Acid to Carbon Dioxide.

Metal-doped graphitic carbon nitride (MCN) materials have shown great promise as effective photocatalysts for the conversion of acetic acid to carbon dioxide under UV–visible irradiation and are superior to pristine carbon nitride (g-C3N4 , CN). In this study, the effects of metal dopants on the physicochemical properties of metal-doped CN samples (Fe-, Cu-, Zn-, FeCu-, FeZn-, and CuZn-doped CN) and their catalytic activity in the photooxidation of acetic acid were investigated and discussed for their correlation, especially on their surface and bulk structures. The materials in the order of highest to lowest photocatalytic activity are FeZn_CN, FeCu_CN, Fe_CN, and Cu_CN (rates of CO2 evolution higher than for CN), followed by Zn_CN, CuZn_CN, and CN (rates of CO2 evolution lower than CN). Although Fe doping resulted in the extension of the light absorption range, incorporation of metals did not significantly alter the crystalline phase, morphology, and specific surface area of the CN materials. However, the extension of light absorption into the visible region on Fe doping did not provide a suitable explanation for the increase in photocatalytic efficiency. To further understand this issue, the materials were analyzed using two complementary techniques, reversed double-beam photoacoustic spectroscopy (RDB-PAS) and electron spin resonance spectroscopy (ESR). The FeZn_CN, with the highest electron trap density between 2.95 and 3.00 eV, afforded the highest rate of CO2 evolution from acetic acid photodecomposition. All Fe-incorporated CN materials and Cu-CN reported herein can be categorized as high activity catalysts according to the rates of CO2 evolution obtained, higher than 0.15 μmol/min−1, or >1.5 times higher than that of pristine CN. Results from this research are suggestive of a correlation between the rate of CO2 evolution via photocatalytic oxidation of acetic acid with the threshold number of free unpaired electrons in CN-based materials and high electron trap density (between 2.95 and 3.00 eV).

Balancing acidogenesis and methanogenesis metabolism in thermophilic anaerobic digestion of food waste under a high loading rate

Achieving a metabolic balance between volatile fatty acid (VFA) production and conversion is a standing challenge in high temperature and organic loading rate anaerobic digestion. A thermophilic anaerobic digestion reactor fed with food waste was therefore operated for 230 days to investigate metabolic performance in acidogenesis and methanogenesis. Results showed a methane yield of 310 mL/g·COD under an organic loading rate (OLR) of 10.0 kg·COD/(m3·d). The VFA concentration of 110 mg/L was low, indicating well-balanced VFA production and conversion metabolism. Highly specific acetic acid and propionic acid methanogenic activity showed satisfactory metabolic capability. Methanosarcina (95.2%) predominated in the high OLR state and increased abundance of Methanothermobactger (4.2%) was also observed. Syntrophic acetic acid oxidation bacterial was not found in different HRT conditions. It is therefore reasonable to speculate cleavage of acetic acid by mixotrophic Methanosarcina. Good acidogenesis and methanogenesis balance promote stable thermophilic AD of food waste under a high OLR.

Use of catalytic wet air oxidation (CWAO) for pretreatment of high-salinity high-organic wastewater

Catalytic wet air oxidation (CWAO) coupled desalination technology provides a possibility for the effective and economic degradation of high salinity and high organic wastewater. Chloride widely occurs in natural and wastewaters, and its high content jeopardizes the efficacy of Advanced oxidation process (AOPs). Thus, a novel chlorine ion resistant catalyst B-site Ru doped LaFe1-xRuxO3-δ in CWAO treatment of chlorine ion wastewater was examined. Especially, LaFe0.85Ru0.15O3-δ was 45.5% better than that of the 6%RuO2@TiO2 (commercial carrier) on total organic carbon (TOC) removal. Also, doped catalysts LaFe1-xRuxO3-δ showed better activity than supported catalysts RuO2@LaFeO3 and RuO2@TiO2 with the same Ru content. Moreover, LaFe0.85Ru0.15O3-δ has novel chlorine ion resistance no matter the concentration of Cl− and no Ru dissolves after the reaction. X-ray diffraction (XRD) refinement, X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), and X-ray absorption fine structure (XAFS) measurements verified the structure of LaFe0.85Ru0.15O3-δ. Kinetic data and density functional theory (DFT) proved that Fe is the site of acetic acid oxidation and adsorption of chloride ions. The existence of Fe in LaFe0.85Ru0.15O3-δ could adsorb chlorine ion (catalytic activity inhibitor), which can protect the Ru site and other active oxygen species to exert catalytic activity. This work is essential for the development of chloride-resistant catalyst in CWAO. [Display omitted]

Self-generated peroxyacetic acid in phosphoric acid plus hydrogen peroxide pretreatment mediated lignocellulose deconstruction and delignification

BackgroundPeroxyacetic acid involved chemical pretreatment is effective in lignocellulose deconstruction and oxidation. However, these peroxyacetic acid are usually artificially added. Our previous work has shown that the newly developed PHP pretreatment (phosphoric acid plus hydrogen peroxide) is promising in lignocellulose biomass fractionation through an aggressive oxidation process, while the information about the synergistic effect between H3PO4 and H2O2 is quite lack, especially whether some strong oxidant intermediates is existed. In this work, we reported the PHP pretreatment system could self-generate peroxyacetic acid oxidant, which mediated the overall lignocellulose deconstruction, and hemicellulose/lignin degradation.ResultsThe PHP pretreatment profile on wheat straw and corn stalk were investigated. The pathways/mechanisms of peroxyacetic acid mediated-PHP pretreatment were elucidated through tracing the structural changes of each component. Results showed that hemicellulose was almost completely solubilized and removed, corresponding to about 87.0% cellulose recovery with high digestibility. Rather high degrees of delignification of 83.5% and 90.0% were achieved for wheat straw and corn stalk, respectively, with the aid of peroxyacetic acid oxidation. A clearly positive correlation was found between the concentration of peroxyacetic acid and the extent of lignocellulose deconstruction. Peroxyacetic acid was mainly self-generated through H2O2 oxidation of acetic acid that was produced from hemicellulose deacetylation and lignin degradation. The self-generated peroxyacetic acid then further contributed to lignocellulose deconstruction and delignification.ConclusionsThe synergistic effect of H3PO4 and H2O2 in the PHP solvent system could efficiently deconstruct wheat straw and corn stalk lignocellulose through an oxidation-mediated process. The main function of H3PO4 was to deconstruct biomass recalcitrance and degrade hemicellulose through acid hydrolysis, while the function of H2O2 was to facilitate the formation of peroxyacetic acid. Peroxyacetic acid with stronger oxidation ability was generated through the reaction between H2O2 and acetic acid, which was released from xylan and lignin oxidation/degradation. This work elucidated the generation and function of peroxyacetic acid in the PHP pretreatment system, and also provide useful information to tailor peroxide-involved pretreatment routes, especially at acidic conditions.Graphical abstract

Does Symmetry Control Photocatalytic Activity of Titania-Based Photocatalysts?

Decahedral anatase particles (DAPs) have been prepared by the gas-phase method, characterized, and analyzed for property-governed photocatalytic activity. It has been found that depending on the reaction systems, different properties control the photocatalytic activity, that is, the particle aspect ratio, the density of electron traps and the morphology seem to be responsible for the efficiency of water oxidation, methanol dehydrogenation and oxidative decomposition of acetic acid, respectively. For the discussion on the dependence of the photocatalytic activity on the morphology and/or the symmetry other titania-based photocatalysts have also been analyzed, that is, octahedral anatase particles (OAP), commercial titania P25, inverse opal titania with and without incorporated gold NPs in void spaces and plasmonic photocatalysts (titania with deposits of gold). It has been concluded that though the morphology governs photocatalytic activity, the symmetry (despite its importance in many cases) rather does not control the photocatalytic performance.

Electrochemical synthesis of ZnS/In2S3 nanocomposite for photocatalytic oxidation of Acetic acid and its substituents, efficiency compared with ZnS, In2S3 and TiO2

ZnS/In 2 S 3 nanocomposite was synthesized by the electrochemical method. The synthesized nanocomposite was characterized by XRD, UV–vis, PL, IR, SEM and EDAX techniques. The X-ray diffraction reveals that the average crystalline size to be 60.3 nm. The band gap of ZnS/In 2 S 3 nanocomposite from Tauc's plot was found to be 3.15 eV. PL spectrum of ZnS/In 2 S 3 nanocomposite over the range 360–450 nm showed that the synthesized nanocomposite is photoluminescent. The photocatalytic activity of the synthesized nanocomposite was examined by the kinetics of photodegradation of Acetic acid and its substituents by volumetric method by using NaOH solution. Taft (LFER) linear free energy relationship was tested, isokinetic temperature β was calculated for oxidation of Acetic acid and its substituents. A plausible mechanism for degradation was proposed. Graphical abstract for the electrochemical synthesis of ZnS/In 2 S 3 nanocomposite.

Current efficiency and mass transfer effects in electrochemical oxidation of C1 and C2 carboxylic acids on boron doped diamond electrodes

The oxidation of acetic, glycolic, glyoxylic, oxalic and formic acid has been studied on boron doped diamond electrodes. Our voltammetry study on rotating disk electrodes highlights clear differences between the carboxylic acids (formic, oxalic, glyoxylic and glycolic acid) that can be oxidized via a direct electron transfer (DET) and acetic acid which can presumably solely be oxidized by •OH radicals formed in the region where water oxidation takes place. In glycolic and glyoxylic oxidation oxalic acid is the main intermediate formed. Surprisingly, glyoxylic acid could not be detected as an intermediate in the glycolic acid oxidation. Chronoamperometric experiments confirm that all compounds except acetic acid react further to CO2, which could be deduced from the electron balances. It was shown that formic, oxalic, glyoxylic and glycolic acid can be selectively oxidized at 2.3 V vs. Ag/AgCl with high current efficiencies, below or close to mass transfer limiting rates. At higher potentials (2.4 V and 2.5 V) simultaneous water electrolysis results in lower current efficiencies. At these potentials the conversion rates can exceed the limiting rates, which might be attributed to effects related to water oxidation (i.e. O2 evolution and •OH radical formation).

Insights into ethanol electro-oxidation over solvated Pt(1 0 0): Origin of selectivity and kinetics revealed by DFT

The use of ethanol fuel in direct ethanol fuel cells has been hindered by the slow kinetics of anodic ethanol electro-oxidation reactions over Pt catalysts. We employ ab initio molecular dynamics simulations and thermodynamic integrations on the solvated Pt(100) model electrode surface with explicit water molecules, to systematically investigate the ethanol electrocatalytic oxidation mechanisms including partial oxidation to acetic acid and complete oxidation to CO2. We find that the ethanol decomposition rate does not limit the overall efficiency of the ethanol electro-oxidation reaction. However, the slow oxidation kinetics of surface intermediates to final products, due to the bonding between intermediates and the Pt surface being too strong, is the main obstacle. We suggest that weakening the surface affinity towards adsorption of the intermediates such as CO, for example by engineering the surface structures (e.g. via alloying), could improve the overall catalytic effeciency for ethanol electro-oxidation reaction.

Mono- and bimetallic (Pt/Cu) titanium(IV) oxide photocatalysts. Physicochemical and photocatalytic data of magnetic nanocomposites' shell.

Surface modification of titania with noble and semi-noble metals resulted in significant enhancement of photocatalytic activity. Presented data, showing the photocatalytic properties of TiO2-M (where M is Pt and/or Cu) photocatalysts were further used as Fe3O4@SiO2/TiO2-M magnetic nanocomposites shells in "Mono- and bimetallic (Pt/Cu) titanium(IV) oxide core-shell photocatalysts with Vis light activity and magnetic separability" [1]. Platinum and copper were photodeposited on four different titania matrices (commercial and self-obtained ones). The prepared photocatalysts were characterized by X-ray diffraction (XRD) analysis, specific surface area measurements using the Brunauer-Emmet-Teller (BET) isotherm, diffuse reflectance spectroscopy (DR-UV/Vis) analysis as well as scanning transmission electron microscopy (STEM) analysis. Photocatalytic properties were investigated in three different reactions: H2 generation, acetic acid oxidation to CO2, and phenol degradation.

Processes of catalytic oxidation for the production of chemicals from softwood biomass

Two alternative routes of softwood catalytic oxidative fractionation to cellulose products and fine chemicals are assessed.Wesuggested to use the process of larch wood peroxide oxidation in the medium acetic acid – water at temperatures 70–100 °C in the presence of soluble catalyst (NH4)6Mo7O24 to produce microcrystalline cellulose (35.0 wt% on wood), microfibrillated cellulose (7.5 wt% on wood) or nanocrystalline cellulose (3.7 wt% on wood) and low molecular weight organic compounds (20 wt% on wood). The developed process reduces the number of technological stages and increase an environmentally safety of nanocelluloses production from wood, compared to traditional technologies.Another suggested process of softwood (pine and larch) fractionation to vanillin (up to 4.7 wt% on wood) and cellulose (up to 34.6 wt% on wood) is based on wood oxidation by oxygen in water–alkaline medium at temperatures 160–180 °C in the presence of suspended catalyst Cu(OH)2. The further acid conversion of cellulose by 2 % H2SO4at 180 °C produces levulinic acid with the yield up to 9.7 wt % on wood.The integration of the processes of dihydroquercetin and arabinogalactan extraction isolation from larch wood, oxidation of extracted wood by oxygen to vanillin and cellulose in the presence of catalyst Cu(OH)2, acid catalyzed conversion of cellulose to levulinic acid and arabinogalactan hydrolysis over solid acid catalyst to arabinose and galactose leads to an increase in the number of target products.FTIR, XRD, SEM, AFM, solid state 13C CP/MAS and chemical methods were used for characterization of cellulose products. Organic compounds were identified by GC, HPLC and GC-MS methods.The two alternative schemes of larch wood catalytic oxidative biorefinery to produce nanocelluloses and fine chemicals have been developed.