The elucidation of the ring-opening reaction mechanism is a critical step towards improving the catalytic performance for the conversion of biomass into value-added chemicals. Herein, we focused on the stepwise C–O bond hydrogenolysis mechanism of oxygen-containing heterocycles (O-heterocycles) into α,ω-diols, in particular THFA to 1,5-PeD, over selective Ni-La(OH)3 in hydrogen-donor isopropanol. A mechanistic study was carried out on a structurally well-defined Ni-La(OH)3, where the mechanism was elucidated using a combination of kinetic and 13C NMR isotope labeling experiments. It was suggested that both Ni nanoparticles and La(OH)3 support play a critical role in the reaction mechanism, where basic hydroxide species of the support initially deprotonate the CH2OH and –OH modified furan, tetrahydrofuran and tetrahydropyran rings, adsorbing them chemically on the catalyst surface. This step is followed by a direct hydride attack on the second carbon atom of these rings, which is proposed to be the key step for ring cleavage, as indicated by the increased deuteration at this position. It is assumed that a catalytic transfer hydrogenolysis reaction (CTH) reaction of THFA is proposed to proceed via the dehydrogenation of isopropanol over isolated Ni species, forming hydrogen species that can be adsorbed on the Ni surface or desorb as H2.

In this work, highly efficient carbon-supported Pd-based catalysts for formic acid dehydrogenation were synthesized by a straightforward wet impregnation-reduction method. The carbon support was obtained from a biomass residue (almond shell) prepared via H3PO4-assisted hydrothermal carbonization (HTC) and thermal activation. This carbon support was doped with nitrogen groups to study the effect on the electronic properties and catalytic performance of the catalysts. Investigating the formation of PdAg alloys with varying Pd:Ag molar ratios resulted in catalysts exhibiting enhanced catalytic activity compared to monometallic Pd counterparts. Notably, the Pd1Ag0.5/NAS catalyst displayed outstanding catalytic performance, achieving an initial TOF of 1716 h-1 (calculated in the first 3 minutes of reaction and expressed per mole of Pd) and maintaining substantial activity over 6 consecutive reaction cycles. This work elucidates the successful synthesis of effective catalysts, emphasizing the influence of nitrogen doping and PdAg alloy composition on catalytic behavior and stability.

Carboligases catalyze the thiamine diphosphate (ThDP) dependent formation of carbon-carbon bonds. These enzymes are prominent biocatalysts for the production of valuable a-hydroxy carbonyl compounds, which serve as key building blocks in the synthesis of various pharmaceuticals and fine chemicals. Carboligases act in selective manner to afford regio- and stereochemically defined products from simple starting materials. This review explores the catalytic prowess of carboligases for synthetic purposes and is aimed at providing a selection tool of enzymes for particular sets of substrates or desired products. The comprehensive overview encompasses structural insights, relationships of the currently known sequence space and practical applications with a focus on recent literature, showcasing carboligases as potent tools for sustainable and efficient synthesis.

Kinetic model development is integral for designing, redesigning, monitoring, and optimizing chemical processes. Of the various approaches used within this field, microkinetic modeling is a crucial tool that focuses on surface events to analyze overall and preferential reaction pathways. This work covers noticeable features of microkinetic modeling for three critical case studies: (i) ammonia to hydrogen, (ii) oxidative coupling of methane to chemicals, and (iii) carbon dioxide hydrogenation for methanol synthesis. We analyze how microkinetic modeling enables predicting and optimizing complex reaction networks, allowing the design of efficient and tailored catalysts with enhanced activity and selectivity.

Aryl bromides and 4-chlorotoluene as an example aryl chloride in the presence of N-heterocyclic carbene (NHC) palladium hydroxo dimers of the type [{Pd(µ-OH)Cl(NHC)}2] (where NHC = IPr, SIPr, IMes, SIMes) undergo an efficient and selective Sonogashira cross-coupling with (hetero)arylacetylenes. The procedure allows the high-throughput and selective synthesis of a broad spectrum of 1,2-diarylacetylenes using 10 ppm of [{Pd(OH)Cl(IPr)}2] as precatalyst. For the coupling of 4-chlorotoluene with phenylacetylene, TON = 560000 was achieved. Hydrogen chloride was observed as a product of the Sonogashira cross-coupling reaction. The formation of the active Pd(0) from the Pd(II) complex was found to proceed via ethanol oxidation. Mechanistic studies showed that water plays a key role in the reaction.

Catalytic oxidation is an efficient method for VOCs elimination. Co₃O₄-based catalysts have been widely studied due to cost-effectiveness and superior low-temperature activity. The construction strategies and structure-activity relationship of Co₃O₄-based catalysts in VOCs oxidation were illustrated in detail, including monometallic Co₃O₄ and multimetallic cobalt-based catalysts. This work provides a theoretical foundation to guide the catalyst construction for low-temperature VOCs oxidation.

Abstract

Volatile organic compounds (VOCs) are a significant source of environmental pollution, posing threats to human safety. With growing concerns about environmental degradation, catalytic oxidation technology emerges as a paramount and widely adopted approach for VOC elimination, renowned for its operational simplicity, energy efficiency, and environmental friendliness. As a representative transition metal catalyst, cobalt-based catalysts have garnered widespread use in VOC catalytic oxidation due to their cost-effectiveness, versatility, and distinctive physicochemical properties. This paper provides a detailed exposition of the construction strategies and structure-activity relationship of Co₃O₄-based catalysts in VOCs oxidation reaction, encompassing both monometallic Co₃O₄ and multimetallic cobalt-based catalysts. Furthermore, it offers a comprehensive summary and discussion of the latest research progress concerning Co₃O₄-based catalysts in practical applications. Concluding with a meticulous analysis, the paper addresses the technical challenges inherent in developing Co₃O₄-based catalysts for VOCs degradation. Additionally, it proposes research directions aimed at overcoming these challenges, contributing to the ongoing discourse on environmental sustainability.

The direct α-alkenylation of nitrile was realized with palladium catalyst for the first time. Both cyano group and alkenyl group in the product can be functionalized, rendering this method a powerful protocol to synthesis a series of useful compounds.

Abstract

A direct α-alkenylation of nitrile compounds was realized with a palladium complex. This method exhibited excellent tolerance toward a variety of α-aryl alkyl nitriles and vinyl bromides, leading to the formation of a series of α-quaternary nitriles containing vinyl groups. Further manipulations of the obtained products were demonstrated, highlighting the potential synthetic utility of this method.

This review describes the overview of mechanistic and kinetics insights for guiding the design of catalysts for selective hydrogenation of functionalized nitroarenes to produce anilines, and summarizes the strategies developed for controlling the selectivity to target product, including isolating active sites, constructing synergistic active sites and regulating local environments of active sites.

Abstract

Selective hydrogenation of functionalized nitroarenes to anilines employed with heterogeneous catalysts is a significant process and widely applied in chemical industry. However, designing high-performance catalysts for these processes remains challenging. Recently, notable advancements have been achieved in synthesis methodologies, characterization techniques, and theoretical calculations, offering opportunities to gain insights into mechanisms. This review summarizes the recent progress in understanding the mechanistic aspects of selective hydrogenation catalysis for functionalized nitroarenes. We initiate by delving into the structure-performance relationship, with the aim of providing a comprehensive understanding of mechanistic and kinetic details in the selective hydrogenation of functionalized nitroarenes. Subsequently, we introduce various strategies for designing high-performance catalysts, categorizing them into three key aspects: isolating active sites, synergizing active sites and regulating local environments of active sites. Finally, we conclude with a concise overview of the current state of this field and provide a forward-looking perspective for future studies, emphasizing the high-performance design and manipulation of catalysts to achieve precise control over selectivity towards target products.

A cyclic deracemization process that utilizes alternately a biocatalytic enantioselective reduction employing (S)-selective methionine sulfoxide reductase from Pseudomonas alcaliphila (paMsr) supplemented with DTT as external reducing equivalent, and a stereo-unselective photocatalytic oxidation reaction using the readily accessible Eosin Y as photocatalyst to achieve chiral sulfoxides is presented. Evaluation of the substrate scope demonstrates a general applicability of this modular system.

Abstract

The synergistic combination of biocatalysis and photocatalysis is emerging as powerful tool for the development of sustainable and atom-efficient synthetic concepts facilitating an enormous portfolio of possible reactions which even goes beyond the capabilities found in nature. Here, a cyclic deracemization process is presented tailored for the synthesis of optically pure sulfoxides which are versatile structural motifs in asymmetric synthesis as well as in bioactive compounds. Enantioselective enzyme-catalyzed reduction of rac-sulfoxides was combined with a stereo-unselective photocatalytic oxidation of the corresponding sulfide intermediate. The utilization of the readily accessible and rather inexpensive photocatalyst Eosin Y increases the usability of this synthetic method. To overcome the incompatibility between the photocatalyst Eosin Y and the biocatalytic step, the cyclic deracemization process was performed in a step-wise fashion via alternated reduction in the darkness and oxidation under illumination. This modular system allowed precise adjustments of reaction parameters yielding the desired sulfoxide targets with up to >99 % ee. Evaluation of the substrate scope including a range of structurally diverse molecules demonstrated its broad applicability.

The different structural-type zeolites (FER, MFI, FAU, BEA) are investigated as catalysts in (bio)isobutanol conversion into linear butenes. The zeolites’ structure and morphology are confirmed by XRD, N2 (77 K) ad(de)sorption, SEM, EDX, XPS, and 27Al, 29Si, 1H MAS NMR, 1H-29Si CP MAS NMR. The nature and strength of acid-base sites are determined by FTIR spectroscopy of adsorbed pyridine, potentiometric titration, and TPD of NH3/CO2/H2O with MS control. The acid-base properties of the zeolites' surfaces influence their catalytic properties in the target process. The higher selectivity towards linear butene isomers achieved over FER and MFI can be explained by the high strength and density of Brønsted acid sites (over 90% of the total surface acidity). MFI might be regarded as a potential material for the creation of novel catalysts for isobutanol conversion into linear butenes at moderate temperatures (448-473 K) since it offers greater operating stability throughout the process.