4-methoxybenzyl Alcohol Research Articles

Crystallographic Fragment Screening of a Bifunctional Proline Catabolic Enzyme Reveals New Inhibitor Templates for Proline Dehydrogenase and L-Glutamate-γ-semialdehyde Dehydrogenase.

The proline catabolic pathway consisting of proline dehydrogenase (PRODH) and L-glutamate-γ-semialdehyde (GSAL) dehydrogenase (GSALDH) catalyzes the four-electron oxidation of L-proline to L-glutamate. Chemical probes to these enzymes are of interest for their role in cancer and inherited metabolic disease. Here, we report the results of a crystallographic fragment-screening campaign targeting both enzymes. A unique aspect of our approach is the screening of both enzymes simultaneously using crystals of the bifunctional PRODH-GSALDH enzyme, proline utilization A (PutA). A 288-fragment library from Zenobia was screened in crystallo in cocktails of six fragments. Validation X-ray crystallography with individual fragments identified seven crystal hits distributed in the PRODH active site, GSALDH aldehyde substrate-binding site, and GSALDH NAD+ adenine-binding site. The fragment bound in the PRODH active site, 4-methoxybenzyl alcohol, is structurally distinct from all known PRODH inhibitors as it lacks an anionic anchor and stabilizes open conformations of the active site, motivating the study of eighteen analogs. In total, thirteen crystal structures with resolutions ranging from 1.32 Å to 1.80 Å were determined, resolving the poses and interactions of seven fragments from the Zenobia library and five analogs of 4-methoxybenzyl alcohol. These results expand the chemical space of probes targeting proline catabolic enzymes and provide new structural information for further inhibitor development.

Nitrogen-doped mesoporous carbon as metal-free catalysts for the aerobic oxidation of alcohols

The selective oxidation of alcohols to carbonyl compounds is a crucial reaction in organic chemistry. In this study, we report the synthesis of nitrogen-doped mesoporous carbon material by hard template method using biomass derivative sucrose and melamine as carbon and nitrogen sources and silica sol as template agent. Using molecular oxygen as the oxidant, the obtained NC-900 exhibits excellent selectivity in the oxidation of primary alcohols to the corresponding aldehydes without generating over-oxidized acid. For example, under optimal reaction conditions, 4-methoxybenzyl alcohol is almost quantitatively converted to 4-methoxybenzaldehyde. The catalytic system showed robust tolerance to sensitive functional groups and demonstrated favorable reaction effects in gram-scale experiments and multi-step, one-pot reaction sequences. The catalyst was reused for 5 times, and its catalytic activity did not decrease significantly. Hammett correlation studies indicated that the reaction favored substrates with electron-donating substituents. Characterization and experimental results indicate that the synergistic effect of graphitic N and mesoporous structure plays a pivotal role in enhancing the catalytic activity of NC-900 in this transformation. The mechanism study shows that the reaction involves free radical process.

Molecular Aroma Composition of Vanilla Beans from Different Origins.

The demand for natural Vanilla has increased rapidly, creating the need for more potential sources of high-quality Vanilla essence. Understanding the geographical influences on the aroma profile of Vanilla is essential. This study demonstrates the first comparative analysis of odorant compositions in the three most important Vanilla varieties: Vanilla planifolia, Vanilla pompona, and Vanilla tahitensis from different origins. Following the screening for odor-active molecules through gas chromatography-olfactometry and aroma extract dilution analysis (GC-O and AEDA), selected compounds were quantified using stable isotope dilution assays (SIDA) and their dose over threshold values (DoTs) were calculated. Vanillin was confirmed as the most important odor-active compound due to its highest DoT value, especially in the V. planifolia sample. Meanwhile, 4-methoxybenzyl alcohol and 4-methoxybenzaldehyde showed higher DoT factors than vanillin in V. pompona and partially in V. tahitensis samples. This indicates their role as discriminative odorants for these varieties. The heightened DoT values of 3-hydroxy-4,5-dimethyl-2(5H)-furanone in Uganda Vanilla samples unveil geographical influences on the odorant profile within V. planifolia species. Additionally, 2-methyl-3-(methyldithio)furan was identified for the first time in Vanilla samples with diverse DoT values from different species and origins.

Selective electrochemical oxidation of organic compounds in a mass transfer-enhanced electrochemical flow reactor (e[sbnd]NETmix)

eNETmix stands as an electrochemical flow reactor engineered to enhance mass transfer. This study aimed at assessing the performance of the eNETmix reactor in the realm of organic electrosynthesis. Specifically, the research focused on the selective electrochemical oxidation of 4-methoxybenzyl alcohol (4-MBA) to p-anisaldehyde (PAA) using a bare fluorine-doped tin oxide (FTO) anode. The efficiency of the process was assessed for distinct current densities (j), Reynolds numbers (Re), supporting electrolyte contents, and substrate initial contents. The eNETmix reactor was extensively compared to a commercial electrochemical flow reactor (MicroFlowCell from ElectroCell, Denmark). eNETmix facilitated the use of a broader range of j (0.8–2.0 mA cm−2versus 0.8 mA cm−2) together with smaller Re (≥190 versus >1750), supporting electrolyte contents (≥1 mM versus ≥30 mM), and substrate initial contents (≥2.0 mM versus ≥3.0 mM) with no loss of PAA production or energy consumption. These findings underscore a remarkable suitability of eNETmix as a reactor for organic electrosynthesis.

Efficient Photocatalytic Partial Oxidation of Aromatic Alcohols by Using ZnIn2S4 under Green Conditions.

The ternary chalcogenide ZnIn2S4 (ZIS) has been synthesized by a simple hydrothermal method in which the carcinogen thiacetamide, universally used as a precursor, has been, for the first time, replaced successfully with the harmless thiourea. ZIS has been used as photocatalyst for the partial oxidation of different aromatic alcohols to their corresponding aldehyde in water solution, under ambient conditions and simulated solar light irradiation. The photocatalytic performance of ZnIn2S4 was better than TiO2 P25. In the presence of ZIS for 4-methoxybenzyl alcohol, piperonyl alcohol, and benzyl alcohol, a selectivity towards the corresponding aldehyde of 99 % for a conversion of 46 %, 75 % for a conversion of 81 %, and 87 % for a conversion of 25 %, respectively, was obtained. For the same alcohols a selectivity of 19 % for a conversion of 41 %, 19 % for a conversion of 13 %, and 16 % for a conversion of 26 %, was observed in the presence of TiO2 P25.

Benchmarking Trisaminocyclopropeniums as Mediators for Anodic Oxidation Reactions.

This report benchmarks a tris(amino)cyclopropenium (TAC) salt as an electron-transfer mediator for anodic oxidation reactions in comparison to two known mediators: a triarylamine and a triarylimidazole derivative. The three mediators have redox potentials, diffusion coefficients, and heterogeneous electron transfer rates similar to those of glassy carbon electrodes in acetonitrile/KPF6. However, they differ significantly in their performance in two electro-organic reactions: anodic fluorination of a dithiane and anodic oxidation of 4-methoxybenzyl alcohol. These differences are rationalized based on variable stability in the presence of reaction components (e.g., NEt3·3HF, lutidine, and Cs2CO3) as well as very different rates of electron transfer with the organic substrate. Overall, this work highlights the advantages and disadvantages of each mediator and provides a foundation for expanding the applications of TACs in electro-organic synthesis moving forward.

Green Metrics Evaluation on The Cannizzaro Reaction of p-Anisaldehyde and Benzaldehyde Under Solvent-Free Conditions

In the pursuit of environmentally responsible chemical processes, we conducted a thorough assessment of the green metrics associated with the Cannizzaro reaction using p-anisaldehyde and benzaldehyde under solvent-free conditions. This research elaborates the application of two different methods i.e., reflux and ultrasonication, applying potassium hydroxide (KOH) as the reagent. The progress of the Cannizzaro reaction was methodically followed via thin-layer chromatography (TLC), and the resulting products were characterized using various techniques, including melting point analysis, Fourier-transform infrared spectroscopy (FTIR), and gas chromatography-mass spectrometry (GC/MS). To measure the environmental impact and sustainability of these reactions, a multifaceted approach was used. Green metrics were evaluated by the state-of-the-art Environmental Assessment Tool for Organic Syntheses (EATOS) software, combined with the Andraos algorithm. Moreover, energy consumption calculations were evaluated. Reasonable analysis of the green metrics results was undertaken in the framework of prevailing literature, permitting to measure the level of eco-friendliness attained. Experimental findings revealed optimal conditions for the Cannizzaro reaction concerning p-anisaldehyde at a temperature of 50 °C for 90 minutes, resulting in remarkable of p-anisyl alcohol and p-anisic acid in 95.16% and 95.04% yields, respectively. Likewise, the reaction involving benzaldehyde reached its peak performance at 50 °C for 2 hours, giving benzyl alcohol and benzoic acid in 96.17% and 97.22% yields, respectively. Overall, the green metrics assessment and energy consumption calculations reliably confirmed that the solvent-free Cannizzaro reaction, when performed via ultrasonication, offers a reasonably greener and more energy-efficient method than the traditional ones. This research highlights the importance of sustainable chemical synthesis practices and their potential to reduce the environmental footprint of chemical processes.

Synthesis of hollow shell TiO2 nanostructures enclosing Au nanoparticles and evaluation of their photoelectrocatalytic activity

Titania hollow shell structures enclosing Au nanoparticles (NPs) Void@Au@TiO2 were synthesized and applied for photoelectrochemical and chemical catalysis. SiO2 nanospheres were first synthesized to be used as templates for the nanostructures. These SiO2 nanospheres were then functionalized with gold nanoparticles (Au NP) using a bifunctional linker APTES [(3-Aminopropyl)triethoxysilane]. A titania coating was carried out on these Au-decorated SiO2 spheres, followed by calcination to enhance the crystallinity of these SiO2@Au@TiO2 structures. Thereafter, the SiO2 template was etched out using NaOH leaving behind Au NPs encapsulated in TiO2 hollow shell nanospheres Void@Au@TiO2. These structures were characterized by using TEM, XRD, UV–Vis-DRS, Raman and FTIR spectroscopy. The catalytic activity was evaluated using the selective oxidation of 4-methoxy benzyl alcohol as a test reaction. Further the photo-electrocatalytic activity of these nanostructures was evaluated.

Shear Stress Triggers Ultrathin-Nanosheet Carbon Nitride Assembly for Photocatalytic H2O2 Production Coupled with Selective Alcohol Oxidation.

Coupled photocatalysis without cocatalysts can maximize the utilization of photons and atoms, which puts forward higher demands on photocatalysts. Polymeric carbon nitride (CN) has become the most promising photocatalyst, but still suffers from major drawbacks of insufficient catalytic sites and low quantum efficiency. Herein, we report a fluid shear stress-assisted molecular assembly to prepare ultrathin-nanosheet-assembled acanthosphere-like CN (ASCN) with nitrogen vacancy (Nv) and carbonyl modification. Shear stress breaks the stacking interactions between layers and cuts the stacked structure into ultrathin layers, which are further reassembled into acanthosphere bundles driven by "centrifugal force". Benefitted greatly from the ultrathin nature that provides more exposed active sites and improves charge carrier separation, ASCN-3 exhibits a 20-fold higher activity than the bulk counterpart toward oxygen reduction to H2O2 coupled with 4-methoxybenzyl alcohol (4-MBA) oxidation to anisaldehyde (AA), with significantly increased turnover frequency (TOF) values (TOF: 1.69 h-1 for H2O2 and 1.02 h-1 for AA). Significantly, ASCN-3 exhibits 95.8% conversion for 4-MBA oxidation with nearly 100% selectivity. High apparent quantum yields of 11.7% and 9.3% at 420 nm are achieved for H2O2 photosynthesis and 4-MBA oxidation. Mechanism studies suggest that carbonyl induces holes concentrated at the neighboring melem unit to directly oxidize the Cα-H bond of 4-MBA to produce carbon radicals, and Nv as oxygen adsorption active site traps electrons to form a superoxide radical that further combines with the shed protons into H2O2. This work presents a simple physical method to break the layered stack of CN for creating hierarchical assembly for coupled photocatalysis.

Facile preparation of CuBi2O4/TiO2 hetero-systems employed for simulated solar-light selective oxidation of 4-methoxybenzyl alcohol model compound

The selective photocatalytic oxidation of organic substances is today considered one of the green techniques to synthesize important starting materials in different technological applications. This work reports an efficient, simple and cheap strategy for the synthesis of a new photocatalytic CuBi2O4-TiO2 (CBO/TiO2) heterosystem at room temperature. The prepared powders were characterized by X-ray diffraction (XRD), UV–Vis diffuse reflectance spectra (DRS), field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. The photocatalytic activity was evaluated by performing a probe reaction, namely the partial oxidation of 4-methoxybenzyl alcohol (4-MBA) to 4-methoxybenzaldehyde (4-MBAld) in aqueous solution under irradiation of simulated sunlight. The CBO/TiO2 coupled systems showed a higher photoactivity than the single photocatalysts reaching a selectivity of 45% towards 4‑methoxy-benzaldehyde with an alcohol conversion of 77% after 4 h of irradiation. Furthermore, although a high alcohol conversion was achieved, the selectivity towards 4-MBAld was significant, unlike what has been reported in the literature for many heterogeneous photocatalytic reactions whose selectivity generally decreases significantly with the increasing conversion of the starting alcohol molecule. The improved photocatalytic activity could be attributed to the partial coverage of the TiO2 surface by CBO which reduces the subsequent oxidation of the formed aldehyde.

De Novo Biosynthesis of Anisyl Alcohol and Anisyl Acetate in Engineered Escherichia coli.

Anisyl alcohol and its ester anisyl acetate are both important fragrance compounds and have a wide range of applications in the cosmetics, perfumery, and food industries. The currently commercially available anisyl alcohol and anisyl acetate are based on chemical synthesis. However, consumers increasingly prefer natural fragrance compounds. Therefore, it is of great significance to construct microbial cell factories to produce anisyl alcohol and anisyl acetate. In this study, we first established a biosynthetic pathway in engineered Escherichia coli MG1655 for the production of anisyl alcohol from simple carbon sources. We further increased the anisyl alcohol production to 355 mg/L by the increasing availability of erythrose-4-phosphate and phosphoenolpyruvate. Finally, we further demonstrated the production of anisyl acetate by overexpressing alcohol acetyltransferase ATF1 for the subsequent acetylation of anisyl alcohol to produce anisyl acetate. To our knowledge, this is the first report on the biosynthesis of anisyl alcohol and anisyl acetate directly from a renewable carbon source.

Selective aqueous oxidation of aromatic alcohols under solar light in the presence of TiO2 modified with different metal species.

A set of metals modified TiO2 photocatalysts were prepared starting from titanium tetraisopropoxyde and different metal precursors to study the influence of the addition of the various foreign agents on the physico-chemical and photocatalytic properties of the catalysts. The powders were characterized by X-ray diffraction, Raman spectroscopy, specific surface area measurements, scanning electron microscopy, energy dispersive X-ray spectroscopy, UV-Vis diffuse reflectance spectroscopy, photoluminescence, temperature programmed desorption after CO2 adsorption. The photocatalytic activity was evaluated using as probe reactions the partial oxidation of three aromatic alcohols: benzyl alcohol (BA), 4-methoxy benzyl alcohol (4-MBA), and 4-hydroxy benzyl alcohol (4-HBA) under simulated solar light irradiation. Different oxidation and selectivity values were obtained for the three substrates depending not only on the type of metals but also on the nature and position of the substituent in the phenyl ring of benzyl alcohol. As a general behaviour, the doped samples allowed the achievement of a greater selectivity especially for 4-MBA even if sometimes with minor conversions. The presence of W or Nb was beneficial for both conversion and selectivity for all the substrates with respect to bare TiO2.

Interfacial Composition of Surfactant Aggregates in the Presence of Fragrance: A Chemical Trapping Study.

In recent years, there has been increasing interest in daily-use chemical products providing a pleasant scent. The added fragrance molecules may induce microstructural transitions of surfactant aggregates, which further affect the physical and chemical properties of the products. Here, the effects of four types of aromatic alcohols (cinnamyl alcohol, phenyl ethanol, phenyl methanol and anisyl alcohol) on cetyltrimethylammonium bromide (CTAB)/KBr aggregates were studied. The combined results from rheology, dynamic light scattering, and transmission electron microscopy measurements showed that cinnamyl alcohol induced significant micellar growth, while increases in micellar growth were less obvious for the other aromatic alcohols. The changes in the interfacial molarities of water, aromatic alcohol, and bromide ions during such transitions were studied using the chemical trapping method. Transitions resulting from added cinnamyl alcohol were accompanied by significant declines in interfacial water and bromide ion molarities, and a rise in interfacial alcohol molarity. The marked decrease in interfacial water molarity was not observed in previous studies of the octanol induced formation of wormlike micelles and vesicles, indicating that a different mechanism was presented in the current system. Nuclear magnetic resonance investigation showed that π–π stacking between cinnamyl alcohols, but not cation–π interactions between alcohols and CTAB headgroups, facilitated the tight packing of alcohol molecules in CTAB aggregates and the repulsion of water from the interfacial region. The current study may provide a theoretical basis for the morphological regulation of surfactant aggregates in the presence of additives.

Mechanistic Investigation of Enhanced Catalytic Selectivity toward Alcohol Oxidation with Ce Oxysulfate Clusters.

Ceria-based materials have been highly desired in photocatalytic reactions due to their redox properties and strong oxygen storage and transfer ability. Herein, we report the structures of one CeCe70 oxysulfate cluster and four MCe70 clusters (M = Cu, Ni, Co, and Fe) with the same Ce70 core. As noted, single-crystal X-ray diffraction confirmed the structures of CeCe70 and the MCe70 series, while Raman spectroscopy indicated an increase in oxygen defects upon the introduction of Cu and Fe ions. The clusters catalyzed the oxidation of 4-methoxybenzyl alcohol under ultraviolet light. CuCe70 and FeCe70 exhibited enhanced reactivity compared to CeCe70 and improved aldehyde selectivity compared to control experiments. In comparison with their homogeneous congeners, the CeCe70/MCe70 clusters altered the location of radical generation from the bulk solution to the clusters' surfaces. Mechanistic studies highlight the role of oxygen defects and specific transition metal introduction for efficient photocatalysis. The mechanistic pathway in this study provides insight into how to select or design a highly selective catalyst for photocatalysis.

Environmental risk assessment of inter-well partitioning tracer compounds shortlisted for the offshore oil and gas industry

Quantifying residual oil saturation (SOR) in the inter-well region of oil and gas reservoirs is key for successfully implementing EOR solutions. Partitioning inter-well tracer tests (PITTs) has become a common method for quantifying SOR. A new group of seven chemicals – pyridine, 2,3-dimethyl pyrazine, 2,6-dimethyl pyrazine, 4-methoxybenzyl alcohol, 3,4-dimethoxybenzyl alcohol, 4-chlorobenzyl alcohol, and 2,6-dichlorobenzyl alcohol – have been proposed as potential partitioning tracers for quantifying SOR. Using these tracers can lead to their environmental release in the marine environment through produced water discharges, with currently limited knowledge on impacts in the marine ecosystem. The primary objective of the present study is to assess the environmental risk of discharging the tracer compounds in the marine environment. We investigated the fate and effect of these tracers in the marine environment. Biodegradability in seawater was measured to understand the fate of tracers in the marine environment. The acute toxicity of tracers was measured in terms of the percent cell viability of a rainbow trout gill cell line (RTgill-W1) and growth inhibition of the algae Skeletonema costatum. The ecotoxicological information obtained from these experiments was used in the dynamic risk and effects assessment model (DREAM) to calculate the tracers’ contribution to the environmental impact factor (EIF). The results from the DREAM simulations suggest no contribution towards EIF values from any of the tracers at the expected back-produced concentrations. Results from simulations at higher concentrations suggest that both pyrazines have the lowest environmental risk, followed by 3,4-dimethoxybenzyl alcohol, 4-methoxybenzyl alcohol, and pyridine; while both chlorobenzyl alcohols show the highest environmental risk.

Synthesis and performance of a composite photocatalyst based on polyester-supported carbon nitride nanosheets for selective oxidation of anisyl alcohol

Heterogeneous photocatalysis represents an essential organic synthesis strategy for the sustainable development of new routes to the highly efficient production of fine chemicals. This work describes a coating method using polyester fibre (PES) to support carbon nitride nanosheets (GCN-TS). PES surface was treated with HNO3 aqueous solutions with different concentrations (0.2 – 5% v/v), which enhanced the adhesion of the GCN-TS on PES fibres. The surface of coated PES treated with 1% v/v HNO3 results in a homogeneous deposition of the photocatalyst and increased hydrophilicity. The photocatalytic synthesis of p-anisaldehyde by oxidation of anisyl alcohol in an aqueous solution assisted by 417 nm visible light-emitting diodes resulted in 95% yield operating in batch mode. The prepared material could be reused, maintaining its photocatalytic performance during five consecutive tests. Aiming at industrial processing, the synthesis of anisaldehyde was performed using the same catalyst in a continuous flow photocatalytic reactor. The performance of the process depends on the residence time of the mixture containing the reactant, as the contact with the immobilised photocatalyst determines the yield.

Electrode reaction of N-hydroxyphthalimide in sulfuric acid-acetonitrile mixed solution as a catalytic mediator for alcohol oxidation

• Highly reversible electrode reaction of NHPI. • 1M sulfuric acide-acetonitrile mixture as eletrolyte. • Catalytic oxidation of alchol as well as in aprotic. • The second eletron oxidation reaction is more complex. The reactivity of the electro-oxidation products of N -hydroxyphthalimide (NHPI) with an aromatic alcohol, 4-methoxybenzyl alcohol (MBA) in a sulfuric acid-acetonitrile mixed solution was investigated. Phthalimide N -oxyl radical (PINO · ), which is produced by one-electron oxidation of NHPI, reacted with MBA in the mixed solution as well as in aprotic solvent. Further oxidation products of PINO · also reacted with MBA but the results showed complex-shaped voltamograms.

Agar plate assay for rapid screening of aryl-alcohol oxidase mutant libraries in Pichia pastoris

Directed evolution is a powerful tool for developing biocatalysts with tailor-made properties for biocatalytic applications. High-throughput activity screening of large mutant libraries generated by e.g. means of directed evolution is usually performed in 96-well microtiter plates requiring, however, time-consuming and laborious enzyme expression, cell harvesting and activity measurements. In addition, automated liquid handling systems are needed to cope with the high number of colonies to be screened. Herein, we developed an agar plate-based assay for simple and fast screening of H2O2-producing aryl-alcohol oxidase (AAO) mutant libraries in Pichia pastoris. Buffered minimal methanol agar plates were supplemented with 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), horseradish peroxidase (HRP) and the target substrate. AAO activity is visualized by formation of green zones around AAO-secreting P. pastoris colonies due to ABTS oxidation by HRP which is fueled with H2O2 by AAO in course of substrate oxidation. Colonies were screened within 24 h for AAO activity using different AAO substrates like veratryl alcohol, p-anisyl alcohol or trans,trans-2,4-hexadien-1-ol and even low AAO activity towards 5-hydroxymethylfurfural could be detected within 48 h. The developed agar plate-based assay can be extended to other substrates and might also be applied for fast and substrate-specific screening of other H2O2-producing oxidases in P. pastoris.

Synthesis of Silica-Based Solid-Acid Catalyst Material as a Potential Osteochondral Repair Model In Vitro

For osteochondral damage, the pH value change of the damaged site will influence the repair efficacy of the patient. For better understanding the mechanism of the acid-base effect, the construction of in vitro model is undoubtedly a simple and interesting work to evaluate the influence. Here, a novel porous silica-based solid-acid catalyst material was prepared by additive manufacturing technology, exhibiting improved eliminating effects of the residue. SEM, FTIR, and TGA were used to characterize the morphology, structure, and thermal stability of the synthesized 3D material. The reaction between 4-methoxybenzyl alcohol and 3, 4-dihydro-2H-pyran was used as a template reaction to evaluate the eliminating performance of the 3D porous material. Solvents were optimized, and three reaction groups in the presence of 3D SiO2, 3D SiO2-SO3H, and 3D SiO2-NH-SO3H, as well as one without catalyst, were compared. In addition, in consideration of the complicated situation of the physiological environment in vivo, universality of the synthesized 3D SiO2-NH-SO3H catalyst material was studied with different alcohols. The results showed that the sulfonic acid-grafted 3D material had excellent catalytic performance, achieving a yield over 95% in only 20 min. Besides, the catalyst material can be recycled at least 10 times, with yields still higher than 90%. Such a solid catalyst material is expected to have great potential in additive manufacturing because the catalyst material is easy-recyclable, renewable and biocompatible. The 3D material with connective channels may also be utilized as an in vitro model for environment evaluation of osteochondral repair in the future.

Au/CeO2 Photocatalyst for the Selective Oxidation of Aromatic Alcohols in Water under UV, Visible and Solar Irradiation

Au nanoparticles supported on CeO2 have been prepared and investigated as photocatalysts for the photocatalytic selective oxidation of benzyl alcohol and 4-methoxybenzyl alcohol to the correspondent benzaldehydes, in aqueous suspensions and room conditions under UV, visible and natural solar light irradiation. Au nanoparticles have been supported by impregnation (1 and 3 wt.%) on two types of CeO2 (i.e., a commercial one and a home prepared oxide obtained in the presence of NaOH as precipitation agent). The Au impregnated samples showed strong visible radiation absorption at 565–570 nm associated to localized surface plasmon resonance (LSPR). The bare CeO2 samples are activated by UV light and resulted virtually inactive under visible irradiation, whereas the presence of Au improved both the conversion of the alcohols and the selectivity of the reaction towards the aldehyde, giving rise to good results, particularly under visible and natural solar light irradiation. The activity of the materials increased by increasing the Au content.