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To make pyrolytic bio‐oil useful as a transportation fuel, the oxygen content must be reduced, and this can be carried out by using catalytic hydrodeoxygenation (HDO) reaction. The greatest challenge is associated with the removal of strongly bound oxygenated groups without saturating the aromatic ring while preserving the number of carbons. However, the development of a stable catalyst that can selectively remove such oxygenated groups with low hydrogen consumption is still challenging. In this context, a systematic study on HDO of vanillin on bimetallic Pd−Pt catalysts was carried out. It aims to study the effect of bimetallic synergy in terms of activity and selectivity to creosol. Metallic nanoparticles of Pd and Pt were synthesized by sol immobilization technique and deposited on TiO2. The conversion of vanillin was correlated to the Pd−Pt atomic ratio, while the production of the creosol was correlated to the Pd(0)/(Pd+Pt) ratio at the surface. Full conversion of vanillin was obtained at low reaction temperature (20 °C) achieving nearly 100 % selectivity to creosol. These results represent a step forward in advancing the development of more efficient and sustainable processes for bio‐oil upgrading. [ABSTRACT FROM AUTHOR]

In this work, solid-state fermentation (SSF) was applied to babassu mesocarp (BM) for the low-cost bioproduction of natural aroma compounds having Trichoderma harzianum (IOC 4042) and Geotrichum candidum (CCT 1205) as microbial agents. Fermentation was carried out using in natura babassu mesocarp (IN-BM) and defatted babassu mesocarp through soxhlet extraction (DEF-BM) as support, impregnated with hydration solutions of three and seven salts. The compounds produced were analyzed using solid phase microextraction (SPME) and gas chromatography coupled with a mass spectrometer (GC-MS). Among several aroma compounds detected, 6-pentyl-α-pyrone (6-PP)—GRAS 3696, coconut aroma; 2-phenylethanol (2-PE)—GRAS 2858, rose and honey aroma; and hexanal—GRAS 2557, green apple aroma, were the compounds that that were detected with the greatest intensity. The highest concentrations (ppm (w/w)) of 6-PP and 2-PE were obtained in DEF-BM using NS7SG (308.17 ± 3.18 and 414.53 ± 1.96), respectively, while for hexanal, the highest concentration (ppm (w/w)) was obtained in IN-BM using NS7SG (210.83 ± 2.14). The results indicate that producing aroma compounds by G. candidum and T. harzianum through BM SSF is viable, generating value-added compounds. [ABSTRACT FROM AUTHOR]

Strong metal–support interaction (SMSI) is a pivotal strategy in thermal catalysis; however, its application in photocatalysis leaves ample area for further development. A method inducing SMSI between earth-abundant metals, such as copper and TiO2, at room temperature, and thus hindering the agglomeration of copper species remains rarely reported. In this work, we achieved SMSI construction of TiO2 overlayers on Cu nanoparticles via a straightforward soft-chemistry method. SMSI coverage is stable even after high-temperature treatment in the air (500 °C), as demonstrated by chemical mapping and surface analysis. The method is more accurate than thermal reduction since it produces a metastable, highly active anatase phase. Interestingly, the TiO2 overlayer induces the formation of four-coordinated copper(II) species surrounded by oxygen atoms, resulting in coexisting CuO2 planes, which were monitored through high-resolution transmission electron microscopy and electron paramagnetic resonance spectroscopy. The stronger interfacial interaction by forming Ti–O–Cu bonding promotes charge carrier separation, producing twice as much H2 than the low interfacial interaction within a conventional photoactive system wherein copper was decorated onto TiO2. Our approach offers a rational design for SMSI materials in photocatalysis, which is extendable to other catalytic reactions. [ABSTRACT FROM AUTHOR]

This study investigated the oxidation of 5-hydroxymethylfurfural (HMF) to produce valuable products such as 2,5-furandicarboxaldehyde (DFF), 5-formyl-2-furancarboxylic acid (FFCA) and 2,5-furandicarboxylic acid (FDCA) through (photo) chemical and enzymatic catalysis. Laccases from different sources, including Aspergillus spp., Pseudomonas cepacea, and Trametes versicolor, were evaluated for their catalytic activity in the HMF oxidation. Laccase from Trametes versicolor (LacTV) emerged as the most effective catalyst, achieving complete conversion of HMF under specific pH conditions. The reaction mechanisms were explored, revealing a preference for the primary alcohol oxidation pathway over the aldehyde, leading to the formation of DFF and subsequent conversion to FFCA and FDCA. The impact of substrate concentration on HMF conversion was examined, revealing optimal conversion at lower HMF concentrations (<100 mM) and reduced performance at higher concentrations (>100 mM). The study also examined the influence of blue light (430 nm) on this reaction, revealing the dependence on light exposure for gC3N4 based catalysts and a negative effect for LacTV. Furthermore, the study introduces a modular flow chemical platform that utilizes Continuous Stirred Tank Reactors (CSTR) in a cascade configuration, the optimization of HMF oxidation. The implementation of this innovative approach has led to the effective synthesis of FDCA, demonstrating an impressive 40-fold increase in productivity compared to the traditional batch system. These results present significant potential for advancing green chemistry and sustainable chemical synthesis, introducing novel possibilities for environmentally friendly HMF oxidation processes. [ABSTRACT FROM AUTHOR]

The hydrodeoxygenation of furfural (FF) over Mo carbides in liquid phase at 200 °C, 30 bar of H2 for 4 h in 2‐butanol was investigated. Unsupported and SiO2‐supported Mo carbide with different crystallographic phases (β‐Mo2C/SiO2 and α‐MoC/SiO2), and in the presence of Cu and Ni as promoters were studied. The reactivation treatment under H2 atmosphere of the passivated Mo carbides was investigated by XAS. The results show that Mo is present in different states of oxidation in the passivated catalysts, with more severe oxidation in the bimetallic systems, in which the original carbides are not restored after reactivation. Finally, the product distribution in the HDO of furfural is modified as a function of catalyst oxidation degree. Using the less oxidized Mo carbide (β‐Mo2C), a higher yield to 2‐methylfuran is obtained, while C10 condensation products are formed for the more oxidized catalysts. [ABSTRACT FROM AUTHOR]

In recent years, the synthesis of bio‐based polymers and compounds has grown due to greater environmental concerns and the need to develop green and sustainable products as substitutes for fossil derivatives. In this context, lignocellulosic biomass is an important source of raw materials, as it is abundant and low‐cost, in addition to its chemical variety. Thus, chemical catalysis and biocatalysis have been important tools for obtaining these high value‐added compounds. With the aim of detecting the current scenario, as well as the main challenges and opportunities in the production of bio‐based polymers through the valorization of biomass, this work carried out a technological investigation of articles published in the last 10 years, establishing a relationship between the conditions of each production route and its main challenges. The results show a growing number of publications in the last 6 years involving the application of biomass‐derived molecules as monomers to obtain various classes of polymers, where polyesters and polyurethanes have been the most studied. The use of heterogeneous chemical catalysts is still the predominant production strategy, due to the extreme conditions required for production. However, the application of enzymes such as lipases to obtain polyesters and microbial biotransformation to obtain polyhydroxyalkanoates have been emerging as promising strategies within the context of biorefineries. Almost all works are at the proof‐of‐concept stage, where most of the molecules produced have been obtained from synthetic starting materials, demonstrating the need to integrate technologies for obtaining monomers directly from biomass and synthesis protocols for the advent of new processes that are more sustainable and competitive with traditional routes. [ABSTRACT FROM AUTHOR]

Exploring the potential of utilizing CO2 for commercial purposes is a promising opportunity, especially in light of the growing research efforts towards CO2 capture, storage, and utilization as well as green H2 production. This review article delves into catalyst features and other technological aspects of a plausible process for the indirect conversion of CO2 into glycolic acid, which involves the following steps: CO2 capture, water electrolysis, CO2 hydrogenation to methanol, catalytic oxidation to formaldehyde, and formaldehyde carbonylation to glycolic acid. We adopt an industrial perspective to address this challenge effectively, thoroughly evaluating different processing alternatives with emphasis on the catalytic systems to optimize glycolic acid production performance. [ABSTRACT FROM AUTHOR]