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Lignin represents the largest aromatic carbon resource in plants, holding significant promise as a renewable feedstock for bioaromatics and other cyclic hydrocarbons in the context of the circular bioeconomy. However, the methoxy groups of aryl methyl ethers, abundantly found in technical lignins and lignin‐derived chemicals, limit their pertinent chemical reactivity and broader applicability. Unlocking the phenolic hydroxyl functionality through O‐demethylation (ODM) has emerged as a valuable approach to mitigate this need and enables further applications. In this review, we provide a comprehensive summary of the progress in the valorization of technical lignin and lignin‐derived chemicals via ODM, both catalytic and non‐catalytic reactions. Furthermore, a detailed analysis of the properties and potential applications of the O‐demethylated products is presented, accompanied by a systematic overview of available ODM reactions. This review primarily focuses on enhancing the phenolic hydroxyl content in lignin‐derived species through ODM, showcasing its potential in the catalytic funneling of lignin and value‐added applications. A comprehensive synopsis and future outlook are included in the concluding section of this review. [ABSTRACT FROM AUTHOR]

In transitioning to a carbon‐neutral chemical industry, the intake of fossil feedstocks will have to be reduced by maximizing end‐of‐life product recycling and introducing alternative feedstocks based on renewable carbon. This perspective article analyses the potential of domestically grown and sourced woody biomass for the supply of renewable carbon for chemicals in Europe. The European chemical industry can become a major consumer of woody biomass in a context where burning wood for energy production is viewed as an unsustainable practice. [ABSTRACT FROM AUTHOR]

Vanillin is a popular and versatile flavor compound, almost entirely produced from petroleum‐derived phenol by a multi‐step chemical synthesis. The process is hazardous to the environment and unsustainable for its fossil oil usage. Therefore, developing environmentally friendly, efficient, and sustainable routes to biobased vanillin is essential. Here, we report on vanillin production from 4‐n‐propylguaiacol (4PG), one of the main components in lignin oil obtained through reductive catalytic fractionation (RCF) of soft wood, by employing recombinant Escherichia coli cells. Conversion is based on the expression of two engineered oxidative enzymes: a 4‐n‐propylguaiacol oxidase and an isoeugenol dioxygenase. A high yield of vanillin, 66% from 4PG in RCF lignin oil was achieved through rounds of optimisation of the whole‐cell conversion process. This high‐performance strategy was readily scaled up to produce vanillin at an unprecedented 18% and 3% yield based on lignin oil and spruce wood respectively. The whole‐cell bioconversion process shows good tolerance even at high loadings of starting material, showcasing the robustness and applicability of the employed biocatalysts. This work paves the way for further development towards the efficient production of high‐titer biobased vanillin using depolymerised lignin as the feedstock. [ABSTRACT FROM AUTHOR]

The reductive catalytic fractionation (RCF) of lignocellulosic biomass is an attractive method for the conversion of lignin toward valuable low‐molecular weight aromatics. A limitation to the upscaling of such technology is represented by the use ofpressurized hydrogen gas. Here, the role of hydrogen gas within the RCF of wheat straw biomass is investigated. The use of H2 is shown to enhance lignin depolymerization, by virtue of an improved hydrogenolysis and hydrogenation of lignin fragments, with a yield of phenolic monomers that increased from ca. 12 wt % of acid‐insoluble lignin in the initial biomass under inert atmosphere to up to ca. 25 wt % under H2 (in methanol, at 250 °C, with Ru/C). The adoption of methanol, ethanol or isopropanol as hydrogen‐donor solvents was also investigated in the absence of H2. Ethanol was found to give the highest yield of monophenolic compounds (up to ≈20 wt %) owing to a better balance between solvolysis, hydrogenolysis, and hydrogenation of lignin. Nevertheless, a substantial loss of the carbohydrate fraction was observed. The use of a lower temperature (200 °C) in combination with H3PO4 resulted in an improved recovery of cellulose in the pulp and in the solubilization of hemicellulose and lignin, with the formation of monosaccharides (≈14 wt % of polysaccharides in the initial biomass) and phenolic monomers (up to 18 wt %, in the absence of H2). Overall, a tradeoff exists between the removal of H2 from the process and the production of low‐molecular weight phenolics during RCF. [ABSTRACT FROM AUTHOR]

Via hydrothermal synthesis of Sn‐Al gels, mild dealumination and ion exchange, a bimetallic Sn‐Ni‐Beta catalyst was prepared which can convert glucose to methyl lactate (MLA) and methyl vinyl glycolate (MVG) in methanol at yields of 71.2 % and 10.2 %, respectively. Results from solid‐state magic‐angle spinning nuclear magnetic resonance, X‐ray photoelectron spectroscopy, transmission electron microscopy, spectroscopic analysis, probe‐temperature‐programmed desorption, and density functional theory calculations conclusively reveal that the openness of the Sn sites, such as by the formation of [(SiO)3−Sn−OH] entities, is governed by an adjacent metal cation such as Ni2+, Co2+, and Mn2+. This relies on the low structure‐defective pore channel, provided by the current synthesis scheme, and the specific silica hydroxyl anchor point is associated with the incorporation of Sn for additional and precise metal ion localization. The presence of metal cations significantly improved the catalytic performance of Sn‐Ni‐Beta for glucose isomerization and conversion to MLA of sugar compared with Sn‐Beta. [ABSTRACT FROM AUTHOR]

Upcoming biorefineries, such as lignin‐first provide renewable aromatics containing unique aliphatic alcohols. In this context, a Cu‐ZrO2 catalyzed hydrogen borrowing approach was established to yield tertiary amine from the lignin model monomer 3‐(3,4‐dimethoxyphenyl)‐1‐propanol and the actual lignin‐derived monomers, (3‐(4‐hydroxyphenyl)‐1‐propanol and dihydroconiferyl alcohol), with dimethylamine. Various industrial metal catalysts were evaluated, resulting in nearly quantitative mass balances for most catalysts. Identified intermediates, side and reaction products were placed into a corresponding reaction network, supported by kinetic evolution experiments. Cu‐ZrO2 was selected as most suitable catalyst combining high alcohol conversion with respectable aliphatic tertiary amine selectivity. Low pressure H2 was key for high catalyst activity and tertiary amine selectivity, mainly by hindering undesired reactant dimethylamine disproportionation and alcohol amidation. Besides dimethylamine model, diverse secondary amine reactants were tested with moderate to high tertiary amine yields. As most active catalytic site, highly dispersed Cu species in strong contact with ZrO2 is suggested. ToF‐SIMS, N2O chemisorption, TGA and XPS of spent Cu‐ZrO2 revealed that imperfect amine product desorption and declining surface Cu lowered the catalytic activity upon catalyst reuse, while thermal reduction readily restored the initial activity and selectivity demonstrating catalyst reuse. [ABSTRACT FROM AUTHOR]

5‐hydroxymethylfurfural (HMF) is an important bio‐derived platform molecule that is generally obtained from hexoses via acid‐catalyzed dehydration. It can be effectively transformed into a variety of value‐added derivatives, thus being an ideal candidate for fossil replacement. Both HMF oxidation and hydrogenation processes enable the synthesis of numerous chemicals, monomers for polymerization, and biofuel precursors. This Review summarizes the most recent advances in heterogeneous catalytic hydroconversion of HMF into valuable chemicals with strong focus on 2,5‐bishydroxymethyl furan (BHMF), 2,5‐bishydroxymethyltetrahydrofuran (BHMTHF), and 2,5‐dimethyltetrahydrofuran (DMTHF). In addition, multifunctional catalytic systems that enable a tunable production of various HMF derived intermediates are discussed. Within this chemistry, the surprising impact of HMF purity on the catalytic performance, such as selectivity and activity, during its upgrading is highlighted. Lastly, the remaining challenges in the field of HMF hydroconversion to the mentioned chemicals are summarized and discussed, taking into account the knowledge gain of catalyst properties and feedstock purity. [ABSTRACT FROM AUTHOR]

The synthesis of novel, renewable lignin‐based protective films with anticorrosive properties is presented in this work. Thermosetting films are prepared by means of tandem UV‐initiated thiol‐yne "click" synthesis and Claisen rearrangement strategy. These films contain high lignin loading, 46–61%, originating from a nickel‐catalyzed birch wood reductive catalytic fractionation (RCF) process. Lignin fractions with varying monomer content are compared before resins preparation, namely a mixture of monomers and oligomers without fractionation, or after fractionation via extraction and membrane separation. This study aims to determine if the separation of lignin monomers and oligomers is necessary for the application as a thermosetting resin. The resulting films exhibit remarkable adhesion to a metal surface and excellent solvent resistance, even after exposure to a corrosive environment. Moreover, those films show superior barrier properties, studied with odd random phase electrochemical impedance spectroscopy (ORP EIS). After 21 days of exposure, the examined films still show impressive high corrosion protection with the low‐frequency impedance ≈1010 Ω cm2 and capacitive behavior. This work demonstrates an interesting proof‐of‐concept where laborious, costly, and energy‐intensive separation of the depolymerized lignin mixture of monomers and oligomers is not necessary for the successful resin synthesis with excellent properties using the applied synthetic strategy. [ABSTRACT FROM AUTHOR]

Sulphides of alpha‐hydroxy thioesters and esters (SAH(T)Es) are important fine chemicals and have great potential as platform molecules. SAH(T)Es are typically synthesized from fossil sources while little is known regarding their synthesis from carbohydrates. We report our findings about the one‐pot chemocatalytic conversion of erythrulose (ERU) to SAH(T)Es. Sn, Mo and W chlorides were the most selective catalysts towards the synthesis of S‐butyl‐4‐butylthio‐2‐hydroxybutanethioate (BBTHBT) in 1‐BuSH. The selectivity towards BBTHBT was impacted by the formation of different thioacetals (TAs). The addition of either KOH, H2O or MeOH was effective to decrease TAs formation and increase selectivity towards BBTHBT (or its ester). A kinetic profile, in situ 13C NMR measurements and experiments at different temperatures complement our studies to unravel the complicated reaction network involved in the conversion of ERU to SAH(T)Es. This insight provides a solid foundation for future improvements in the sustainable synthesis of SAH(T)Es. [ABSTRACT FROM AUTHOR]

A catalytic route is developed to synthesize bio‐renewable catechol from softwood‐derived lignin‐first monomers. This process concept consists of two steps: 1) O‐demethylation of 4‐n‐propylguaiacol (4‐PG) over acidic beta zeolites in hot pressurized liquid water delivering 4‐n‐propylcatechol (4‐PC); 2) gas‐phase C‐dealkylation of 4‐PC providing catechol and propylene over acidic ZSM‐5 zeolites in the presence of water. With large pore sized beta‐19 zeolite as catalyst, 4‐PC is formed with more than 93 % selectivity at nearly full conversion of 4‐PG. The acid‐catalyzed C‐dealkylation over ZSM‐5 zeolite with medium pore size gives a catechol yield of 75 %. Overall, around 70 % catechol yield is obtained from pure 4‐PG, or 56 % when starting from crude 4‐PG monomers obtained from softwood by lignin‐first RCF biorefinery. The selective cleavage of functional groups from biobased platform molecules through a green and sustainable process highlights the potential to shift feedstock from fossil oil to biomass, providing drop ins for the chemicals industry. [ABSTRACT FROM AUTHOR]

Fossil‐based platform molecules such as ethylene and ethylene oxide currently serve as the primary feedstock for the C2‐based chemical industry. However, in the search for a more sustainable chemical industry, fossil‐based resources may preferentially be replaced by renewable alternatives, provided there is realistic economic feasibility. This Review compares and critically discusses several production routes toward bio‐based structural analogues of ethylene oxide and the required adaptations for their implementation in state‐of‐the‐art C2‐based chemical processes. For example, glycolaldehyde, a structural analogue obtainable from carbohydrates by atom‐economic retro‐aldol reactions, may replace ethylene oxide's leading role. This alternative chemical route may not only allow the carbon footprint of conventional chemicals production to be lowered, but the introduction of a bio‐based pathway may also contribute to safer production processes. Where possible, challenges, drawbacks, and prospects are highlighted. [ABSTRACT FROM AUTHOR]

This article, titled "Inside Back Cover: Advancements and Perspectives toward Lignin Valorization via O-Demethylation," discusses the process of lignin O-demethylation and its potential applications. The authors, Bert U. W. Maes and Bert F. Sels, provide a comprehensive summary of the advancements and perspectives in this field. Lignin, a component of plant cell walls, contains methoxy groups that limit its reactivity and usefulness. Through O-demethylation, lignin can be transformed into a product rich in phenolic functionality, which has broader applications. The article is authored by Xian Wu, Ewoud Smet, Francesco Brandi, Deepak Raikwar, Zhenlei Zhang, Bert U. W. Maes, and Bert F. Sels. [Extracted from the article]

This article, titled "Advancements and Perspectives toward Lignin Valorization via O-Demethylation," discusses the process of O-demethylation in lignin, which is a type of plant material. The authors, Bert U. W. Maes and Bert F. Sels, provide a comprehensive review of the advancements and potential applications of O-demethylation in lignin. They explain that the presence of methoxy groups in lignin limits its reactivity and usefulness, but through O-demethylation, lignin can be transformed into a product rich in phenolic functionality, which has broader applications. The article is authored by Xian Wu, Ewoud Smet, Francesco Brandi, Deepak Raikwar, Zhenlei Zhang, Bert U. W. Maes, and Bert F. Sels. [Extracted from the article]

The cover image is based on the Perspective Feasibility of wood as a renewable carbon feedstock for the production of chemicals in Europe by Wouter Arts et al., https://doi.org/10.1002/bbb.2575. [ABSTRACT FROM AUTHOR]

An efficient conversion of biorenewable ferulic acid into bio‐catechol has been developed. The transformation comprises two consecutive defunctionalizations of the substrate, that is, C−O (demethylation) and C−C (de‐2‐carboxyvinylation) bond cleavage, occurring in one step. The process only requires heating of ferulic acid with HCl (or H2SO4) as catalyst in pressurized hot water (250 °C, 50 bar N2). The versatility is shown on a variety of other (biorenewable) substrates yielding up to 84 % di‐ (catechol, resorcinol, hydroquinone) and trihydroxybenzenes (pyrogallol, hydroxyquinol), in most cases just requiring simple extraction as work‐up. [ABSTRACT FROM AUTHOR]

The production of drop‐in chemicals from bio‐based renewable sources is gaining a lot of momentum due to proven negative impact of fossil‐based economy on environment and society. In this Review, various bio‐derived platform molecules are assessed as renewable alternatives to fossil resources for the catalytic production of acrylates. Acrylic acid and its esters are key building blocks of a large number of high‐value oligomers and polymers in the current industry. In spite of the encouraging successes reported on gram or lab‐scale, real implementation of bio‐based examples remain scarce mainly due to the current high cost and limited availability of the bio‐based substrates. As lactic acid and their derivatives are one of the most promising feedstocks for bio‐acrylate production, they are the main focus of this Review. The key to the feedstock: Acrylic acid and esters are key monomers for large number of high‐value polymers. Various platform molecules originated from different biomass feedstock were assessed as potential substituents of current propylene‐based industrial production. This Review focuses on the use of lactic acid and their derivatives as the promising feedstock for bio‐based acrylates production. [ABSTRACT FROM AUTHOR]

A catalytic process to produce glycolide, the cyclic dimer of glycolic acid (GA), is proposed. Glycolide is the key building block of the biodegradable plastic polyglycolic acid. Instead of the current industrial two‐step route, which involves the polycondensation of GA and a subsequent backbiting reaction, a new route based on the gas‐phase transesterification of methyl glycolate (MGA) over a fixed catalyst bed is presented. With specific supported TiO2 catalysts, a high glycolide selectivity of 75–78 % can be achieved at the thermodynamically‐limited equilibrium conversion of MGA (54 % at 300 °C, 5.6 vol% MGA, 1 atm). The absence of solvent and the continuous nature of the process should allow for easy product separation and recycling of unconverted esters, while the few side‐products, i. e. linear alkyl glycolate dimers and trimers seem recoverable via methanolysis. The reaction is compared to the cyclization of other α‐hydroxy esters, such as methyl lactate to lactide, over the same catalysts, in terms of kinetics and thermodynamics. The absence of a methyl substitution on the α‐carbon seems to lead to faster cyclization kinetics of MGA when compared to methyl lactate or the double‐substituted methyl‐2‐hydroxy‐isobutyrate. Contrarily, glycolide production is less favored thermodynamically compared to lactide. The absence of glycolide decomposition at temperatures up to 300 °C however allows to increase equilibrium conversion by taking the endergonic reaction to higher temperatures. Green plastics! A novel process to produce glycolide, the cyclic dimer of glycolic acid, is proposed, via gas‐phase transesterification of methyl glycolate. Glycolide is the key building block of the biodegradable plastic polyglycolic acid. [ABSTRACT FROM AUTHOR]

Abstract: A new route to lactide, which is a key building block of the bioplastic polylactic acid, is proposed involving a continuous catalytic gas‐phase transesterification of renewable alkyl lactates in a scalable fixed‐bed setup. Supported TiO2/SiO2 catalysts are highly selective to lactide, with only minimal lactide racemization. The solvent‐free process allows for easy product separation and recycling of unconverted alkyl lactates and recyclable lactyl intermediates. The catalytic activity of TiO2/SiO2 catalysts was strongly correlated to their optical properties by DR UV/Vis spectroscopy. Catalysts with high band‐gap energy of the supported TiO2 phase, indicative of a high surface spreading of isolated Ti centers, show the highest turnover frequency per Ti site. [ABSTRACT FROM AUTHOR]

Short amines, such as ethanolamines and ethylenediamines, are important compounds in today's bulk and fine chemicals industry. Unfortunately, current industrial manufacture of these chemicals relies on fossil resources and requires rigorous safety measures when handling explosive or toxic intermediates. Inspired by the elegant working mechanism of aldolase enzymes, a novel heterogeneously catalyzed process-reductive aminolysis-was developed for the efficient production of short amines from carbohydrates at low temperature. High-value bio-based amines containing a bio-derived C2 carbon backbone were synthesized in one step with yields up to 87 C%, in the absence of a solvent and at a temperature below 405 K. A wide variety of available primary and secondary alkyl- and alkanolamines can be reacted with the carbohydrate to form the corresponding C2-diamine. The presented reductive aminolysis is therefore a promising strategy for sustainable synthesis of short, acyclic, bio-based amines. [ABSTRACT FROM AUTHOR]

Alternative biobased bisphenols from lignocellulosic biomass are not only favorable to reduce the environmental impact of current petroleum-derived plastics, but they can be simultaneously beneficial for health issues related to bisphenol A (BPA). Additionally, conventional BPA synthesis entails a large excess of unrecoverable homogeneous acid catalyst (e.g., HCl) or unrecyclable thermolabile sulfonated resins. In this report, zeolites are proposed as recoverable and thermally stable solid acids for the Brønsted-acid-catalyzed condensation between 4-methylguaiacol and formaldehyde to selectively produce renewable bisphenols. It is found that the Brønsted-acid-site density plays a pivotal role for catalyst performance. In particular, the cheap and environmentally friendly FAU 40 exhibits outstanding activity (turnover frequency of 496 h−1) and selectivity (>95 %), outperforming even the best benchmark catalyst. Additionally, the zeolite can be easily recycled without activity loss after regeneration by coke burn-off. The catalytic zeolite system also seems very promising for other lignin-derived alkylphenols, alkylguaiacols, and alkylsyringols. [ABSTRACT FROM AUTHOR]

A practical and scalable synthesis for the mass production of well-ordered mesoporous silica-carbon composites by using a fast rotary-evaporation-induced self-assembly method in the absence of any additional support is presented. [ABSTRACT FROM AUTHOR]

Abstract: This Editorial presents the Special Issue on Supported Molecular Catalysts as a forum to discuss recent advances in the immobilization and heterogenization of molecular catalysts. The scope ranges from organic synthesis and highly selective reactions through to photocatalysis and electrocatalysis, including advances in enzyme immobilization methodology. The outcome is a wide spectrum of papers encompassing all the old formal domains of catalysis research of both primary and secondary research. [ABSTRACT FROM AUTHOR]

Viral hepatitis is a major public health problem affecting millions of people worldwide. Long-term consequences are the development of liver cirrhosis and hepatocellular carcinoma. The aim of the study was to assess outcomes and costs of treating patients with chronic hepatitis C in clinical practice in Germany. We carried out a prospective noninterventional study. Information on treatment outcomes, resource utilization and quality of life was provided by 281 physicians throughout Germany. Data of 3708 monoinfected HCV-patients treated between 2008 and 2011 were analysed. Therapy consisted of peginterferon/ribavirin. Mean age of patients was 43.7 years, 60.3% were male and estimated duration of infection was 13.6 years. Predominantly genotype 1 (61.3%) or 3 (28.5%) infections were observed. Sustained viral response ( SVR)-rates in most frequently observed genotypes were 49.2% in GT-1 and 61.9% in GT-3 treatment-naive patients (Relapser: GT-1: 35.3% and GT-3: 57.3%; Nonresponder: GT-1: 25.0% and GT-3: 33.3%). Average treatment costs were lowest in treatment-naive patients (€18 965) and higher in patients who failed previous treatments (relapsers: €24 753; nonresponders: €19 511). Differences according to genotype were observed. Average costs per SVR in treatment-naive patients were €44 744 for GT-1 and €22 218 for GT-3. Treatment was associated with a decrease in quality of life; post-treatment quality of life was higher in patients achieving SVR. Our insight on real-life treatment outcomes and costs can serve as a reference for a comparison with other treatments. There is high need for short-term and long-term cost-effectiveness analysis in real-life settings as newly introduced treatment strategies with direct acting antivirals result in high SVR-rates but are more costly. [ABSTRACT FROM AUTHOR]

Hierarchical zeolites are a class of superior catalysts which couples the intrinsic zeolitic properties to enhanced accessibility and intracrystalline mass transport to and from the active sites. The design of hierarchical USY (Ultra-Stable Y) catalysts is achieved using a sustainable postsynthetic room temperature treatment with mildly alkaline NH4OH (0.02 m) solutions. Starting from a commercial dealuminated USY zeolite (Si/Al = 47), a hierarchical material is obtained by selective and tuneable creation of interconnected and accessible small mesopores (2–6 nm). In addition, the treatment immediately yields the NH4+ form without the need for additional ion exchange. After NH4OH modification, the crystal morphology is retained, whereas the microporosity and relative crystallinity are decreased. The gradual formation of dense amorphous phases throughout the crystal without significant framework atom leaching rationalizes the very high material yields (>90%). The superior catalytic performance of the developed hierarchical zeolites is demonstrated in the acid-catalyzed isomerization of α-pinene and the metal-catalyzed conjugation of safflower oil. Significant improvements in activity and selectivity are attained, as well as a lowered susceptibility to deactivation. The catalytic performance is intimately related to the introduced mesopores, hence enhanced mass transport capacity, and the retained intrinsic zeolitic properties. [ABSTRACT FROM AUTHOR]

The synthesis of ordered mesoporous silica-carbon composites was explored by employing TEOS and sucrose as the silica and carbon precursor respectively, and the triblock copolymer F127 as a structure-directing agent via an evaporation-induced self-assembly (EISA) process. It is demonstrated that the synthesis procedures allow for control of the textural properties and final composition of these silica-carbon nanocomposites via adjustment of the effective SiO2/C weight ratio. Characterization by SAXS, N2 physisorption, HRTEM, TGA, and 13C and 29Si solid-state MAS NMR show a 2D hexagonal mesostructure with uniform large pore size ranging from 5.2 to 7.6 nm, comprising of separate carbon phases in a continuous silica phase. Ordered mesoporous silica and non-ordered porous carbon can be obtained by combustion of the pyrolyzed nanocomposites in air or etching with HF solution, respectively. Sulfonic acid groups can be readily introduced to such kind of silica-carbon nanocomposites by a standard sulfonation procedure with concentrated sulfuric acid. Excellent acid-catalytic activities and selectivities for the dimerization of styrene to produce 1,3-diphenyl-1-butene and dimerization of α-methylstyrene to unsaturated dimers were demonstrated with the sulfonated materials. [ABSTRACT FROM AUTHOR]

Valorization of lignin is essential for the economics of future lignocellulosic biorefineries. Lignin is converted into novel polymer building blocks through four steps: catalytic hydroprocessing of softwood to form 4-alkylguaiacols, their conversion into 4-alkylcyclohexanols, followed by dehydrogenation to form cyclohexanones, and Baeyer-Villiger oxidation to give caprolactones. The formation of alkylated cyclohexanols is one of the most difficult steps in the series. A liquid-phase process in the presence of nickel on CeO2 or ZrO2 catalysts is demonstrated herein to give the highest cyclohexanol yields. The catalytic reaction with 4-alkylguaiacols follows two parallel pathways with comparable rates: 1) ring hydrogenation with the formation of the corresponding alkylated 2-methoxycyclohexanol, and 2) demethoxylation to form 4-alkylphenol. Although subsequent phenol to cyclohexanol conversion is fast, the rate is limited for the removal of the methoxy group from 2-methoxycyclohexanol. Overall, this last reaction is the rate-limiting step and requires a sufficient temperature (>250 °C) to overcome the energy barrier. Substrate reactivity (with respect to the type of alkyl chain) and details of the catalyst properties (nickel loading and nickel particle size) on the reaction rates are reported in detail for the Ni/CeO2 catalyst. The best Ni/CeO2 catalyst reaches 4-alkylcyclohexanol yields over 80 %, is even able to convert real softwood-derived guaiacol mixtures and can be reused in subsequent experiments. A proof of principle of the projected cascade conversion of lignocellulose feedstock entirely into caprolactone is demonstrated by using Cu/ZrO2 for the dehydrogenation step to produce the resultant cyclohexanones (≈80 %) and tin-containing beta zeolite to form 4-alkyl-ε-caprolactones in high yields, according to a Baeyer-Villiger-type oxidation with H2O2. [ABSTRACT FROM AUTHOR]

In the valorization of α-pinene, which is an important biomass intermediate derived from turpentine oil, hierarchical (mesoporous) zeolites represent a superior class of catalysts. Hierarchical USY, ZSM-5, and beta zeolites have been prepared, characterized, and catalytically evaluated, with the aim of combining the highest catalytic performance with the most sustainable synthetic protocol. These zeolites are prepared by alkaline treatment in aqueous solutions of NH4OH, NaOH, diethylamine, and NaOH complemented with tetrapropylammonium bromide. The hierarchical USY zeolite is the most attractive catalyst of the tested series, and is able to combine an overall organic-free synthesis with an up to sixfold activity enhancement and comparable selectivity over the conventional USY zeolite. This superior performance relates to a threefold greater activity than that of the commercial standard, namely, H2SO4/TiO2. Correlation of the obtained benefits to the amount of solid lost during the postsynthetic modifications highlights that the highest activity gains are obtained with minor leaching. Furthermore, a highly zeolitic character, as determined by bulk XRD, is beneficial, but not crucial, in the conversion of α-pinene. The alkaline treatments not only result in a higher overall activity, but also a more functional external surface area, attaining up to four times the pinene conversions per square nanometer. The efficiency of the hierarchical USY zeolite is concomitantly demonstrated in the conversion of limonene and turpentine oil, which emphasizes its industrial potential. [ABSTRACT FROM AUTHOR]

Ternary Ag/Magnesia-silica catalysts were tested in the direct synthesis of 1,3-butadiene from ethanol. The influence of the silver content and the type of silica source on catalytic performance has been studied. Prepared catalysts were characterized by 29Si NMR, N2 sorption, small-angle X-ray scattering measurements, XRD, environmental scanning electron microscopy with energy dispersive X-ray analysis (ESEM/EDX), FTIR spectroscopy of adsorbed pyridine and CO2, temperature-programmed desorption of CO2 and UV/Vis diffuse reflectance spectroscopy. Based on these characterization results, the catalytic performance of the catalysts in the 1,3-butadiene formation process was interpreted and a tentative model explaining the role of the different catalytically active sites was elaborated. The balance of the active sites is crucial to obtain an active and selective catalyst to form 1,3-butadiene from ethanol. The optimal silver loading is 1-2 wt % on a MgO-silica support with a molar Mg/Si ratio of 2. The silver species and basic sites (MgO pairs and basic OH groups) are of prime importance in the 1,3-butadiene production, catalyzing mainly the ethanol dehydrogenation and the aldol condensation, respectively. [ABSTRACT FROM AUTHOR]

ABSTRACT A series of hyperbranched polyacenaphthenequinones has been prepared by superelectrophilic aromatic substitution of (substituted) acenaphthenequinone and 1,3,5-tris-(4-phenoxybenzoyl)benzene via a facile A2 + B3 approach. Because of the strongly increased reactivity of the second A functionality, gelation was efficiently avoided during the polymerization. The structure of the resulting polymer was characterized by NMR spectroscopy and gel permeation chromatography. Further modification of the hyperbranched polyacenaphthenequinone was explored both on the acenaphthenequinone and aromatic moieties. Moreover, the polymer modified through sulfonation was investigated as a water-soluble acid catalyst for the degradation of biomass resources. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2596-2603 [ABSTRACT FROM AUTHOR]

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Transition from petroleum- to biomass-based fuel economy will require new conversion strategies. In a petroleum refinery, particular hydrocarbon fractions from crude oil are catalytically converted into high-grade fuels. Certain zeolite catalysts are performing exceptionally well. Unlike petroleum fractions, biomass-derived compounds have a high oxygen content requiring low-temperature catalytic aqueous phase processes for selective conversion and stability of zeolite catalysts in hot liquid water. It will be shown that recent developments in zeolite synthesis and modification allow adapting zeolite properties to achieve selective conversion of biomass compounds/fractions as well. [ABSTRACT FROM AUTHOR]

A straightforward synthetic route to chiral metal-organic frameworks is proposed that relies on an acid-base interaction between an acid linker and a chiral primary amino acid derived diamine organocatalyst. High ee values for the aldol condensation of linear ketones and aromatic aldehydes are reported with this heterogeneous catalyst. Three consecutive catalyst reuse experiments demonstrated that the majority of the activity was preserved, as was the enantioselectivity. [ABSTRACT FROM AUTHOR]

Objective The aim of the study was to identify risk factors associated with pre-transplant fecal carriage of extended-spectrum β-lactamase ( ESBL)-producing Enterobacteriaceae in liver transplant recipients. Patients and methods Over a 3-year period (January 2009-December 2011), 317 patients who underwent liver transplantation were screened preoperatively for fecal carriage of ESBL-producing Enterobacteriaceae. Risk factors for fecal carriage were investigated by univariate analysis and stepwise logistic regression. Results Of the 317 patients screened, 50 (15.7%) harbored an ESBL-producing isolate. Previous infection with an ESBL-producing organism had developed during the last 6 months in 20% of fecal carriers versus in none of the non-carriers. Other variables associated with fecal carriage were a model for end-stage liver disease score ≥25, pre-transplant stay in the intensive care unit ≥48 h, hospital stay ≥10 days in the last 6 months, a history of spontaneous bacterial peritonitis ( SBP), exposure to a β-lactam agent in the last month, and prophylaxis with norfloxacin. Independent predictors of fecal carriage in the multivariate logistic regression model were exposure to a β-lactam agent in the month preceding transplantation (odds ratio [ OR] = 7.8, confidence interval [ CI] = 4-15.5, P < 0.001), and a history of SBP ( OR = 2.4, CI = 1.1-4.9, P = 0.02). Conclusions Previous infection with an ESBL-producing isolate, recent exposure to a β-lactam agent, and a history of SBP are risk factors for preoperative fecal carriage of ESBL-producing Enterobacteriaceae in liver transplant recipients. Patients at risk of fecal carriage should receive intraoperative prophylaxis and, when necessary, empiric postoperative antimicrobial treatment that includes coverage for these organisms. [ABSTRACT FROM AUTHOR]

Gram-negative bacilli are unusual agents of skin and soft tissue infections. Most previous cases have been reported in cirrhotic or immunocompromised patients, including a single case in a liver transplant recipient. The present report describes 3 cases of fatal skin or soft tissue infections caused by Escherichia coli that occurred in the postoperative course of liver transplantation. The 3 patients were profoundly immunosuppressed as a result of pre-transplant cirrhosis and the postoperative administration of a potent immunosuppressive therapy. Skin and soft tissue infections developed within the first week after liver transplantation, while graft liver function was satisfactory. The 3 patients presented with fever and skin lesions with or without bullae. Despite prompt appropriate antibiotic therapy and surgical debridement, the outcome was rapidly fatal (24 h on average). E. coli was isolated from subcutaneous tissues in 2 cases and from several blood cultures in the third one. The 3 isolates belonged to distinct phylogenetic groups, and did not harbor most of the virulence factors usually reported in extraintestinal pathogenic E. coli isolates. Our report suggests that E. coli can cause severe skin or soft tissue infection in the postoperative course of liver transplantation. The onset of infection is very early and the outcome is extremely poor, despite prompt adapted medical and surgical treatment. Host factors, rather than E. coli bacterial virulence potential, appear to be the major determinants of severity in these patients. [ABSTRACT FROM AUTHOR]

α-Hydroxy acids (AHAs) such as lactic acid are considered platform molecules in the biorefinery concept and have high-end applications in solvents and biodegradable polyester plastics. The synthesis of AHAs with a four-carbon backbone structure is a recently emerging field. New biomass-related routes towards their production could stimulate their practical use in new polyester plastics. Herein, we report the unique catalytic activity of soluble tin metal salts for converting tetroses, namely erythrulose and erythrose, into new four-carbon-backbone AHAs such as methyl vinylglycolate and methyl-4-methoxy-2-hydroxybutanoate. An in situ NMR study together with deuterium labeling experiments and control experiments with intermediates allowed us to propose a detailed reaction pathway. [ABSTRACT FROM AUTHOR]

The catalytic valorization of cellulose is currently subject of intense research. Isosorbide is among the most interesting products that can be formed from cellulose as it is a potential platform molecule and can be used for the synthesis of a wide range of pharmaceuticals, chemicals, and polymers. A promising direct route from cellulose to isosorbide is presented in this work. The strategy relies on a one-pot bifunctional catalytic concept, combining heteropoly acids, viz. H4SiW12O40, and redox catalysts, viz. commercial Ru on carbon, under H2 pressure. Starting from pure microcrystalline cellulose, a rapid conversion was observed, resulting in over 50 % isosorbide yield. The robustness of the developed system is evidenced by the conversion of a range of impure cellulose pulps obtained by organosolv fractionation, with isosorbide yields up to 63 %. Results were compared with other (ligno)cellulose feedstocks, highlighting the importance of fractionation and purification to increase reactivity and convertibility of the cellulose feedstock. [ABSTRACT FROM AUTHOR]

Carbon nanofibers (CNFs) are a class of graphitic support materials with considerable potential for catalytic conversion of biomass. Earlier, we demonstrated the hydrolytic hydrogenation of cellulose over reshaped nickel particles attached at the tip of CNFs. The aim of this follow-up study was to find a relationship between the acid/metal balance of the Ni/CNFs and their performance in the catalytic conversion of cellulose. After oxidation and incipient wetness impregnation with Ni, the Ni/CNFs were characterized by various analytical methods. To prepare a selective Ni/CNF catalyst, the influences of the nature of oxidation agent, Ni activation, and Ni loading were investigated. Under the applied reaction conditions, the best result, that is, 76 % yield in hexitols with 69 % sorbitol selectivity at 93 % conversion of cellulose, was obtained on a 7.5 wt % Ni/CNF catalyst prepared by chemical vapor deposition of CH4 on a Ni/γ-Al2O3 catalyst, followed by oxidation in HNO3 (twice for 1 h at 383 K), incipient wetness impregnation, and reduction at 773 K under H2. This preparation method leads to a properly balanced Ni/CNF catalyst in terms of Ni dispersion and hydrogenation capacity on the one hand, and the number of acidic surface-oxygen groups responsible for the acid-catalyzed hydrolysis on the other. [ABSTRACT FROM AUTHOR]

F. Bert, B. Huynh, F. Dondero, J.R. Johnson, C. Paugam-Burtz, F. Durand, J. Belghiti, D. Valla, R. Moreau, M.-H. Nicolas-Chanoine. Molecular epidemiology of Escherichia coli bacteremia in liver transplant recipients. Transpl Infect Dis 2011: 13: 359-365. All rights reserved Abstract: The characteristics of Escherichia coli strains causing bacteremia in profoundly immunosuppressed patients such as transplant recipients are undefined. The phylogenetic group and the virulence genotype of 57 distinct E. coli strains that caused bacteremia in 53 liver transplant recipients were investigated, and the association of these characteristics with host factors and in-hospital mortality was examined. Phylogenetic groups A, B1, B2, and D accounted for 39%, 10%, 25%, and 26% of the isolates, respectively. The most prevalent virulence genes were fyuA (yersiniabactin system: 70%) and iutA (aerobactin system: 63%), whereas hlyA (alpha-hemolysin) and cnf1 (cytotoxic necrotizing factor 1) occurred in only 14% and 12% of isolates, respectively. Most virulence genes were significantly more prevalent among group B2 and D isolates, vs. group A and B1 isolates. The overall rate of in-hospital mortality after E. coli bacteremia was 20%. Predictors of mortality included onset of bacteremia within 30 days of transplantation or during the intensive care unit stay, and non-urinary source and cutaneous source, but not E. coli phylogenetic group or virulence profile. Compared with historical E. coli bloodstream isolates from non-transplant patients, those from liver transplant recipients are characterized by a higher prevalence of groups A and B1 isolates and reduced virulence gene content. This finding can be explained by the severely immunocompromised status of the patients and the predominance of abdominal-source bacteremic episodes. Time of onset and source of bacteremia, not bacterial characteristics, predict mortality. [ABSTRACT FROM AUTHOR]

S. Janny, F. Bert, F. Dondero, F. Durand, P. Guerrini, P. Merckx, M.H. Nicolas-Chanoine, J. Belghiti, J. Mantz, C. Paugam-Burtz. Microbiological findings of culture-positive preservation fluid in liver transplantation. Transpl Infect Dis 2011: 9-14. All rights reserved Bacterial and fungal infections are the leading cause of mortality in liver transplant (LT) recipients. Few studies have examined the incidence of culture-positive preservation fluid (PF) and the outcome of related recipients. The aim of this study was to determine the incidence and the microbiologic findings of PF positive cultures, and to evaluate the impact on morbidity and mortality of LT recipients. A retrospective analysis of PF cultures performed after 477 LTs from cadavaric grafts between January 2001 and February 2008 was conducted. Forty-five (9.5%) PFs were found to be positive with 1 or 2 pathogens. The demographic profiles of recipients of PF with positive or negative cultures were similar. Enterobacteriaceae species were the most frequent organisms ( n=30), followed by Staphylococcus aureus ( n=5), coagulase-negative staphylococci ( n=5), enterococci ( n=4), and yeasts ( n=3). Mortality rate at 1 month was not significantly different in recipients with positive or sterile PF cultures (88.1% vs. 87.7%, respectively). The rate of bacteremia among LT recipients with positive or negative PF cultures was not statistically different. Systemic infections caused by the pathogen cultured from the PF occurred in 8 (18%) of the 45 recipients, including bacteremia (4/8) or intra-abdominal sepsis (5/8). Causative organisms were Enterobacteriaceae species ( n=5), Candida species ( n=2), and Enterococcus faecium ( n=1). Among the 8 patients who developed infection with the PF organism, 4 (50%) died in the intensive care unit (ICU) vs. an ICU mortality rate of 8% (3/37) in those who did not develop infection with the PF organism ( P<0.05). Infection occurred less frequently in recipients who received antimicrobial therapy with activity against the PF isolate than in those without appropriate treatment (41% vs. 3.8%, P<0.005). Those who develop infection with organisms recovered from PF cultures appear to have high early mortality rates; therefore, appropriate antimicrobial therapy against organisms cultured from PF should be given. [ABSTRACT FROM AUTHOR]