Structure Engineering of Ni/SiO2 Vegetable Oil Hydrogenation Catalyst via CeO2.

Inspired by our finding that metallic Ni particles could be uniformly distributed on a reduced CeO2 surface and stabilized on Ce3+ sites, we suppose a possible improvement in the activity and selectivity of the MgNi/SiO2 vegetable oil hydrogenation catalyst by increasing the surface metal Ni availability via modification by ceria. The proposed approach involved the addition of a CeO2 modifier to the SiO2 carrier and as a catalyst component. Evaluation of the structure, reducibility, and surface and electronic states of the CeO2-doped MgNi/SiO2 catalyst was performed by means of the Powder X-ray diffraction (PXRD), Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) combined with High-resolution transmission electron microscopy (HRTEM), Temperature-programmed reduction with hydrogen (H2-TPR), and H2-chemisortion techniques. So far, no studies related to this approach of designing Ni/SiO2 catalysts for the partial hydrogenation of vegetable oil have been reported. The added ceria impact was elucidated by comparing fatty acid compositions obtained by the catalysts at an iodine value of 80. In summary, tuning the hydrogenation performance of Ni-based catalysts can be achieved by structural reconstruction using 1 wt.% CeO2. The introduction mode changed the selectivity towards C18:1-cis and C18:0 fatty acids by applying ceria as a carrier modifier, while hydrogenation activity was improved upon ceria operation as the catalyst dopant.

Control of proton transport and hydrogenation in double-gated graphene.

The basal plane of graphene can function as a selective barrier that is permeable to protons1,2 but impermeable to all ions3,4 and gases5,6, stimulating its use in applications such as membranes1,2,7,8, catalysis9,10 and isotope separation11,12. Protons can chemically adsorb on graphene and hydrogenate it13,14, inducing a conductor-insulator transition that has been explored intensively in graphene electronic devices13-17. However, both processes face energy barriers1,12,18 and various strategies have been proposed to accelerate proton transport, for example by introducing vacancies4,7,8, incorporating catalytic metals1,19 or chemically functionalizing the lattice18,20. But these techniques can compromise other properties, such as ion selectivity21,22 or mechanical stability23. Here we show that independent control of the electric field, E, at around 1 V nm-1, and charge-carrier density, n, at around 1 × 1014 cm-2, in double-gated graphene allows the decoupling of proton transport from lattice hydrogenation and can thereby accelerate proton transport such that it approaches the limiting electrolyte current for our devices. Proton transport and hydrogenation can be driven selectively with precision and robustness, enabling proton-based logic and memory graphene devices that have on-off ratios spanning orders of magnitude. Our results show that field effects can accelerate and decouple electrochemical processes in double-gated 2D crystals and demonstrate the possibility of mapping such processes as a function of E and n, which is a new technique for the study of 2D electrode-electrolyte interfaces.

Protocol for preparation of electrifiable carbon membrane reactor for non-oxidative alkane dehydrogenation.

A membrane reactor (MR) offers a solution to overcome thermodynamic equilibrium limitations by enabling in situ product separation, enhancing product yields and energy efficiency. Here we present a protocol for synthesizing a carbon MR that couples a H2-permeable carbon molecular sieve hollow fiber membrane and a metal supported on zeolite catalyst for non-oxidative propane and ethane dehydrogenation. We describe steps for catalyst preparation, membrane fabrication, and MR construction. The as-developed MR has significant improvements in alkene yield and a record-high stability. For complete details on the use and execution of this protocol, please refer to Liu et al.1.

Selective lignin arylation for biomass fractionation and benign bisphenols.

Lignocellulose is mainly composed of hydrophobic lignin and hydrophilic polysaccharide polymers, contributing to an indispensable carbon resource for green biorefineries1,2. When chemically treated, lignin is compromised owing to detrimental intra- and intermolecular crosslinking that hampers downstream process3,4. The current valorization paradigms aim to avoid the formation of new C-C bonds, referred to as condensation, by blocking or stabilizing the vulnerable moieties of lignin5-7. Although there have been efforts to enhance biomass utilization through the incorporation of phenolic additives8,9, exploiting lignin's proclivity towards condensation remains unproven for valorizing both lignin and carbohydrates to high-value products. Here we leverage the proclivity by directing the C-C bond formation in a catalytic arylation pathway using lignin-derived phenols with high nucleophilicity. The selectively condensed lignin, isolated in near-quantitative yields while preserving its prominent cleavable ß-ether units, can be unlocked in a tandem catalytic process involving aryl migration and transfer hydrogenation. Lignin in wood is thereby converted to benign bisphenols (34-48 wt%) that represent performance-advantaged replacements for their fossil-based counterparts. Delignified pulp from cellulose and xylose from xylan are co-produced for textile fibres and renewable chemicals. This condensation-driven strategy represents a key advancement complementary to other promising monophenol-oriented approaches targeting valuable platform chemicals and materials, thereby contributing to holistic biomass valorization.

Protocol to operate a large-scale CO2 hydrogenation process for formic acid production.

Formic acid is a viable product of CO2 utilization. Here, we present a protocol for designing and operating a pilot-scale formic acid production plant with a 10 kg/day capacity produced via CO2 hydrogenation. We describe the essential process specifications required for successful operation, including prevention of corrosion and formic acid decomposition. We then detail procedures for steady-state operation of the individual units. This protocol provides the necessary information for further scale-up and commercialization of the CO2 hydrogenation process. For complete details on the use and execution of this protocol, please refer to Kim et al.1.

Tandem hydrogenation/hydrogenolysis of furfural to 2-methylfuran over multifunctional metallic Cu nanoparticles supported ZIF-8 catalyst.

Catalytic transfer hydrogenation (CTH), that employs protic solvents as hydrogen sources to alleviate the use of molecular hydrogen H2, has gained great attention. This work, reports multifunctional, metallic Cu nanoparticles supported ZIF-8 material for CTH of furfural to a highly valued fuel additive, 2-methylfuran (2-MF) using 2-propanol. Of all as-synthesized xCu(yM)/ZIF-8 catalysts with varied NaBH4 concentration (yM) and Cu loading (x), 11Cu(1.5 M)/ZIF-8 exhibited higher catalytic activity with > 99 % FAL conversion and 93.9 % 2-MF selectivity. This is ascribed to its high specific surface area, and existence of optimum amount of Lewis acid-base sites along with Cu0 species, which are responsible for hydrogenation of furfural to furfuryl alcohol and subsequent hydrogenolysis to produce 2-MF. The present work reports a highly efficient and stable, metal-MOF hybrid material for CTH of FAL to 2-MF, which is one among the best reports available in literature, therewith suggests a promising approach for bio-oil upgradation.

FPNC Net: A hydrogenation catalyst image recognition algorithm based on deep learning.

The identification research of hydrogenation catalyst information has always been one of the most important businesses in the chemical industry. In order to aid researchers in efficiently screening high-performance catalyst carriers and tackle the pressing challenge at hand, it is imperative to find a solution for the intelligent recognition of hydrogenation catalyst images. To address the issue of low recognition accuracy caused by adhesion and stacking of hydrogenation catalysts, An image recognition algorithm of hydrogenation catalyst based on FPNC Net was proposed in this paper. In the present study, Resnet50 backbone network was used to extract the features, and spatially-separable convolution kernel was used to extract the multi-scale features of catalyst fringe. In addition, to effectively segment the adhesive regions of stripes, FPN (Feature Pyramid Network) is added to the backbone network for deep and shallow feature fusion. Introducing an attention module to adaptively adjust weights can effectively highlight the target features of the catalyst. The experimental results showed that the FPNC Net model achieved an accuracy of 94.2% and an AP value improvement of 19.37% compared to the original CenterNet model. The improved model demonstrates a significant enhancement in detection accuracy, indicating a high capability for detecting hydrogenation catalyst targets.

Asymmetric hydrogenation of ketimines with minimally different alkyl groups.

Asymmetric catalysis enables the synthesis of optically active compounds, often requiring the differentiation between two substituents on prochiral substrates1. Despite decades of development of mainly noble metal catalysts, achieving differentiation between substituents with similar steric and electronic properties remains a notable challenge2,3. Here we introduce a class of Earth-abundant manganese catalysts for the asymmetric hydrogenation of dialkyl ketimines to give a range of chiral amine products. These catalysts distinguish between pairs of minimally differentiated alkyl groups bound to the ketimine, such as methyl and ethyl, and even subtler distinctions, such as ethyl and n-propyl. The degree of enantioselectivity can be adjusted by modifying the components of the chiral manganese catalyst. This reaction demonstrates a wide substrate scope and achieves a turnover number of up to 107,800. Our mechanistic studies indicate that exceptional stereoselectivity arises from the modular assembly of confined chiral catalysts and cooperative non-covalent interactions between the catalyst and the substrate.

Use of carboxymethyl cellulose as binder for the production of water-soluble catalysts.

Bio-based polymers are materials of high interest given the harmful environmental impact that involves the use of non-biodegradable fossil products for industrial applications. These materials are also particularly interesting as bio-based ligands for the preparation of metal nanoparticles (MNPs), employed as catalysts for the synthesis of high value chemicals. In the present study, Ru (0) and Rh(0) Metal Nanoparticles supported on Sodium Carboxymethyl cellulose (MNP(0)s-CMCNa) were prepared by simply mixing RhCl3x3H2O or RuCl3 with an aqueous solution of CMCNa, followed by NaBH4 reduction. The formation of MNP(0)s-CMCNa was confirmed by FT-IR and XRD, and their size estimated to be around 1.5 and 2.2 nm by TEM analysis. MNP(0)s-CMCNa were employed for the hydrogenation of (E)-cinnamic aldehyde, furfural and levulinic acid. Hydrogenation experiments revealed that CMCNa is an excellent ligand for the stabilization of Rh(0) and Ru(0) nanoparticles allowing to obtain high conversions (>90 %) and selectivities (>98 %) with all substrates tested. Easy recovery by liquid/liquid extraction allowed to separate the catalyst from the reaction products, and recycling experiments demonstrated that MNPs-CS were highly efficiency up to three times in best hydrogenation conditions.

Core-Shell Gold Nanoparticles@Pd-Loaded Covalent Organic Framework for In Situ Surface-Enhanced Raman Spectroscopy Monitoring of Catalytic Reactions.

A core-shell nanostructure of gold nanoparticles@covalent organic framework (COF) loaded with palladium nanoparticles (AuNPs@COF-PdNPs) was designed for the rapid monitoring of catalytic reactions with surface-enhanced Raman spectroscopy (SERS). The nanostructure was prepared by coating the COF layer on AuNPs and then in situ synthesizing PdNPs within the COF shell. With the respective SERS activity and catalytic performance of the AuNP core and COF-PdNPs shell, the nanostructure can be directly used in the SERS study of the catalytic reaction processes. It was shown that the confinement effect of COF resulted in the high dispersity of PdNPs and outstanding catalytic activity of AuNPs@COF-PdNPs, thus improving the reaction rate constant of the AuNPs@COF-PdNPs-catalyzed hydrogenation reduction by 10 times higher than that obtained with Au/Pd NPs. In addition, the COF layer can serve as a protective shell to make AuNPs@COF-PdNPs possess excellent reusability. Moreover, the loading of PdNPs within the COF layer was found to be in favor of avoiding intermediate products to achieve a high total conversion rate. AuNPs@COF-PdNPs also showed great catalytic activities toward the Suzuki-Miyaura coupling reaction. Taken together, the proposed core-shell nanostructure has great potential in monitoring and exploring catalytic processes and interfacial reactions.

Protocol for electrocatalytic hydrogenation of 5-hydroxymethylfurfural using H and flow cells.

Recently, there has been a growing interest in using sustainable energy to decrease lignin monomers to generate high-value-added products. Here, we present a protocol for electrocatalytic hydrogenation of 5-hydroxymethylfurfural. We describe steps for catalyst preparation, performing electrocatalytic experiments, high-performance liquid chromatography analysis, and in situ infrared reflection-absorption spectroscopy testing. The synthesized catalyst used in this reaction exhibits enhanced selectivity and Faradaic efficiency in NaClO4 solution. For complete details on the use and execution of this protocol, please refer to Zhang et al.1.

Green preparation of CaO-based CO2 adsorbent by calcium-induced hydrogenation of shell wastes at room/moderate temperature.

Capturing CO2 using clamshell/eggshell-derived CaO adsorbent can not only reduce carbon emissions but also alleviate the impact of trash on the environment. However, organic acid was usually used, high-temperature calcination was often performed, and CO2 was inevitably released during preparing CaO adsorbents from shell wastes. In this work, CaO-based CO2 adsorbent was greenly prepared by calcium-induced hydrogenation of clamshell and eggshell wastes in one pot at room/moderate temperature. CO2 adsorption experiments were performed in a thermogravimetric analyzer (TGA). The adsorption performance of the adsorbents obtained from the mechanochemical reaction (BM-C/E-CaO) was superior to that of the adsorbents obtained from the thermochemical reaction (Cal-C/E-CaO). The CO2 adsorption capacity of BM-C-CaO at 650 °C is up to 36.82 wt%, but the adsorption decay rate of the sample after 20 carbonation/calcination cycles is only 30.17%. This study offers an alternative energy-saving method for greenly preparing CaO-based adsorbent from shell wastes.

Late-Stage Saturation of Drug Molecules.

The available methods of chemical synthesis have arguably contributed to the prevalence of aromatic rings, such as benzene, toluene, xylene, or pyridine, in modern pharmaceuticals. Many such sp2-carbon-rich fragments are now easy to synthesize using high-quality cross-coupling reactions that click together an ever-expanding menu of commercially available building blocks, but the products are flat and lipophilic, decreasing their odds of becoming marketed drugs. Converting flat aromatic molecules into saturated analogues with a higher fraction of sp3 carbons could improve their medicinal properties and facilitate the invention of safe, efficacious, metabolically stable, and soluble medicines. In this study, we show that aromatic and heteroaromatic drugs can be readily saturated under exceptionally mild rhodium-catalyzed hydrogenation, acid-mediated reduction, or photocatalyzed-hydrogenation conditions, converting sp2 carbon atoms into sp3 carbon atoms and leading to saturated molecules with improved medicinal properties. These methods are productive in diverse pockets of chemical space, producing complex saturated pharmaceuticals bearing a variety of functional groups and three-dimensional architectures. The rhodium-catalyzed method tolerates traces of dimethyl sulfoxide (DMSO) or water, meaning that pharmaceutical compound collections, which are typically stored in wet DMSO, can finally be reformatted for use as substrates for chemical synthesis. This latter application is demonstrated through the late-stage saturation (LSS) of 768 complex and densely functionalized small-molecule drugs.

Synthesis of Chiral 1,2-Amino Alcohol-Containing Compounds Utilizing Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation of Unprotected α-Ketoamines.

Herein, we disclose a facile synthetic strategy to access an important class of drug molecules that contain chiral 1,2-amino alcohol functionality utilizing highly effective ruthenium-catalyzed asymmetric transfer hydrogenation of unprotected α-ketoamines. Recently, the COVID-19 pandemic has caused a crisis of shortage of many important drugs, especially norepinephrine and epinephrine, for the treatment of anaphylaxis and hypotension because of the increased demand. Unfortunately, the existing technologies are not fulfilling the worldwide requirement due to the existing lengthy synthetic protocols that require additional protection and deprotection steps. We identified a facile synthetic protocol via a highly enantioselective one-step process for epinephrine and a two-step process for norepinephrine starting from unprotected α-ketoamines 1b and 1a, respectively. This newly developed enantioselective ruthenium-catalyzed asymmetric transfer hydrogenation was extended to the synthesis of many 1,2-amino alcohol-containing drug molecules such as phenylephrine, denopamine, norbudrine, and levisoprenaline, with enantioselectivities of >99% ee and high isolated yields.

Driving an ecological transformation: unleashing multi-objective optimization for hydrogenated compressed natural gas in a decarbonization perspective.

Integrating hydrogen with CNG is crucial for carbon neutrality and environmental goals, as it enhances flame temperature, reduces emissions, and combats global warming. This study employs the CHEMKIN tool to examine combustion characteristics, including adiabatic flame temperature, mole fraction, normalization, and production rate, in H2-CNG mixtures under various atmospheric and operating conditions. Blending 50% hydrogen with CNG results in significant changes, including a temperature increase from 2322 to 2344 K when the hydrogen content is at 50%. The introduction of hydrogen causes a notable 30-35% reduction in CH4 mole fraction and a simultaneous 26.6% increase in C-normalized CH4 production. Free radicals play a role in affecting CO2 production, with the normalization of CO species increasing from 0.068 to 0.087. Through NSGA-II multi-objective optimization methods, the study identifies a 50% H2-50% CNG blend as the optimal choice for thermal and environmental performance. The study explores the energy and environmental impacts of incorporating hydrogen into CNG-air combustion, with a specific focus on the effects of 50% H2 blending with CNG. Hydrogen blending benefits from elevated adiabatic flame temperature and increased free radical formation, ultimately leading to emission reduction. These findings firmly establish H2-CNG mixtures as promising environmentally friendly alternatives with superior combustion characteristics. Their potential paves the way for significant progress towards achieving carbon neutrality and combating climate change through cleaner, more efficient fuel options.

Proportions of trans fatty acids in erythrocytes of Canadian adults before the prohibition of partially hydrogenated oils in foods: results from the Canadian Health Measures Survey 2012-2015.

BACKGROUND: The partially hydrogenated oil (PHO) prohibition came into effect in Canada in September 2018 to reduce the intakes of total trans fatty acids (t-TFAs) and industrially produced TFAs (i-TFAs). OBJECTIVES: We aimed to estimate the red blood cell (RBC) proportions of t-TFA (primary objective) and total 18:1 TFA (secondary objective) of adults in Canada before the PHO prohibition and to identify the population subgroups at risk of higher TFA intakes. METHODS: We pooled data from 4025 adult participants of the cross-sectional Canadian Health Measures Survey cycles 3 and 4 (2012-2015). We estimated mean proportions, relative to total fatty acids (FAs), of RBC t-TFA and 18:1 TFA and their associations with sociodemographic, health, and lifestyle characteristics using multiple linear regression models. RESULTS: The nonadjusted mean RBC proportions of t-TFA and total 18:1 TFA were 0.59% (95% CI: 0.54, 0.63) and 0.27% (95% CI: 0.25, 0.29), respectively. In the adjusted models, the same participant characteristics were associated with t-TFA and 18:1 TFA but differences were generally smaller for 18:1 TFA than for t-TFA. Race, BMI, and alcohol intake were independently associated with RBC t-TFA and 18:1 TFA. Asian and Black participants had lower RBC t-TFA (-0.05% and -0.10% of total FA, respectively) than White participants. Obesity and high risk alcohol drinking were associated with slightly lower (≤0.06%) t-TFA proportions than lower adiposity and alcohol intake concentrations, respectively. CONCLUSIONS: Pre-PHO prohibition in food in Canada, t-TFA proportions were relatively low compared with a proposed threshold of 1% of total RBC FAs, over which cardiovascular disease risk may be higher. Previous voluntary initiatives to reduce i-TFA in the food supply may explain these relatively low RBC t-TFA concentrations. Some population subgroups had higher baseline RBC TFA than other subgroups, but the physiological implications of these small differences, at relatively low baseline RBC TFA proportions, remain to be determined.

Transfer Hydrogenation of Vinyl Arenes and Aryl Acetylenes with Ammonia Borane Catalyzed by Schiff Base Cobalt(II) Complexes.

A series of bench-stable Co(II) complexes containing hydrazone Schiff base ligands were evaluated in terms of their activity and selectivity in carbon-carbon multiple bond transfer hydrogenation. These cobalt complexes, especially a Co(II) precatalyst bearing pyridine-2-yl-N(Me)N=C-(1-methyl)imidazole-2-yl ligand, activated by LiHBEt3, were successfully used in the transfer hydrogenation of substituted styrenes and phenylacetylenes with ammonia borane as a hydrogen source. Key advantages of the reported catalytic system include mild reaction conditions, high selectivity and tolerance to functional groups of substrates.

Biomimetic Dehydrogenation of Non-Conventional Lignin Monomers on Cellulose Ferulate Interfaces.

Cellulose ferulate, synthesized by Mitsunobu reaction, is shaped into thin films and also used as an aqueous dispersion to perform artificial lignin polymerization on anchor groups. This biomimetic approach is carried out in a Quartz crystal microbalance with a dissipation monitoring (QCM-D) device to enable online monitoring of the dehydrogenation, applying H2O2 and adsorbed horseradish peroxidase (HRP). The systematic use of phenylpropanoids with different oxidation states, i.e., ferulic acid, coniferyl aldehyde, coniferyl alcohol, and eugenol allowed to conclude structure-property relationships. Both the deposited material, as well as the surface roughness increased with the hydrophobicity of the monomers. Beyond surface characterizations, py-GC-MS, HSQC NMR spectroscopy and Size exclusion chromatography (SEC) measurements revealed the linkage types ß-ß, ß-5, 5-5, and ß-O-4, as well as the oligomeric character of the dehydrogenation products. All samples possessed an antibacterial activity against B. subtilis and can be used in the field of antimicrobial biomaterials.

Socialane, a Nonaprenyl Terpene Hydrocarbon Surface Lipid from the Collembola Hypogastrura socialis.

Springtails use unique compounds for their outermost epicuticular wax layer, often of terpenoid origin. We report here the structure and synthesis of socialane, the major cuticular constituent of the Collembola Hypogastrura socialis. Socialane is also the first regular nonaprenyl terpene with a cyclic head group. The saturated side chain has seven stereogenic centers, making the determination of the configuration difficult. We describe here the identification of socialane and a synthetic approach using the building blocks farnesol and phytol, enantioselective hydrogenation, and α-alkylation of sulfones for the synthesis of various stereoisomers. NMR experiments showed the presence of an anti-configuration of the methyl groups closest to the benzene ring and that the other methyl groups of the polyprenyl side-chain are not uniformly configured. Furthermore, socialane is structurally different from [6+2]-terpene viaticene of the closely related H. viatica, showing species specificity of the epicuticular lipids of this genus and hinting at a possible role of surface lipids in the communication of these gregarious arthropods.

Copper-catalysed dehydrogenation or lactonization of C(sp3)-H bonds.

Cytochrome P450 enzymes are known to catalyse bimodal oxidation of aliphatic acids via radical intermediates, which partition between pathways of hydroxylation and desaturation1,2. Developing analogous catalytic systems for remote C-H functionalization remains a significant challenge3-5. Here, we report the development of Cu(I)-catalysed bimodal dehydrogenation/lactonization reactions of synthetically common N-methoxyamides through radical abstractions of the γ-aliphatic C-H bonds. The feasibility of switching from dehydrogenation to lactonization is also demonstrated by altering reaction conditions. The use of a readily available amide as both radical precursor and internal oxidant allows for the development of redox-neutral C-H functionalization reactions with methanol as the sole side product. These C-H functionalization reactions using a Cu(I) catalyst with loading as low as 0.5 mol.% is applied to the diversification of a wide range of aliphatic acids including drug molecules and natural products. The exceptional compatibility of this catalytic system with a wide range of oxidatively sensitive functionality demonstrates the unique advantage of using a simple amide substrate as a mild internal oxidant.