Hydrogenation Of Aldehydes Research Articles

Catalytic utility of PNN-based MnI pincer complexes in the synthesis of quinolines and transfer hydrogenation of carbonyl derivatives.

This manuscript describes the synthesis of a triazolyl-pyridine-based phosphine, N-((diphenylphosphaneyl)methyl)-N-methyl-6-(1-phenyl-1H-1,2,3-triazol-4-yl)pyridin-2-amine, [2,6-{(PPh2)CH2N(Me)(C5H3N)(C2HN3C6H5)}] (1) (here onwards referred to as PNN) and its cationic and neutral MnI complexes and catalytic applications. The reaction of 1 with Mn(CO)5Br afforded a cationic complex [Mn(CO)3(PNN)]Br (2), which is highly stable in solid state, but in solution it gradually loses one of the CO groups to form a neutral complex [Mn(CO)2(PNN)Br] (3). Complex 2 on treatment with AgBF4 also yielded a cationic complex [Mn(CO)3(PNN)]BF4 (4). These complexes efficiently promoted the synthesis of quinoline derivatives via acceptor-less dehydrogenative coupling of 2-aminobenzyl alcohol and ketones, with complex 3 showing the highest activity with a very low catalyst loading (0.03 mol%) at 110 °C. Complex 3 (0.5 mol%) also showed excellent catalytic activity in the transfer hydrogenation of ketones and aldehydes to form respective secondary and primary alcohols.

ZnCl2-catalysed transfer hydrogenation of carbonyls and chemoselective reduction of the CC bond in α,β-unsaturated ketones.

This manuscript describes chemoselective reduction of CC in α,β-unsaturated ketones and the transfer hydrogenation of aldehydes and ketones catalysed by ZnCl2-phosphinamino-triazolyl-pyridine (0.5 mol%) using KOH/iPrOH as a H2 source. A detailed mechanistic study using DFT calculations (B3LYP-D3/def2-TZVP) revealed the key role of metal-ligand cooperation (MLC) in the catalytic reaction demonstrating the non-innocent behaviour of the phosphine ligand.

Selective Hydrogenation of Cinnamaldehyde, Furanic, and Aromatic Aldehydes over a Z-Scheme Heterojunction Photocatalyst Constituted of Pd NPs Supported on g-C3N4/ZnO Nanocomposite

Selective Hydrogenation of Cinnamaldehyde, Furanic, and Aromatic Aldehydes over a Z-Scheme Heterojunction Photocatalyst Constituted of Pd NPs Supported on g-C₃N₄/ZnO Nanocomposite

Enteromorpha Prolifera Polysaccharide-Derived Injectable Hydrogel for Fast Intraoperative Hemostasis and Accelerated Postsurgical Wound Healing Following Tumor Resection.

Intraoperative bleeding and delayed postsurgical wound healing caused by persistent inflammation can increase the risk of tumor recurrence after surgical resection. To address these issues, Enteromorpha prolifera polysaccharide (PEP) with intrinsic potentials for hemostasis and wound healing, is chemically modified into aldehyde-PEP and hydrazine-PEP. Thereby, an injectable double-network hydrogel (OPAB) is developed via forming dual dynamic bonding of acylhydrazone bonds between the decorated aldehyde and hydrazine groups and hydrogen bonds between hydroxyl groups between boric acid and PEP skeletons. The OPAB exhibits controllable shape-adaptive gelation (35.0 s), suitable mechanical properties, nonstimulating self-healing (60 s), good wet tissue adhesion (30.9kPa), and pH-responsive biodegradability. For in vivo models, owing to these properties, OPAB can achieve rapid hemostasis within 30 s for the liver hemorrhage, and readily loading of curcumin nanoparticles to remarkably accelerate surgical wound closure by alleviating inflammation, re-epithelialization, granulation tissue formation, and collagen deposition. Overall, this multifunctional injectable hydrogel is a promising material that facilitates simultaneous intraoperative hemorrhage and postsurgical wound repair, holding significant potential in the clinical managements of bleeding and surgical wounds for tumor resection.

Strategic use of crude H2 for the catalytic reduction of carbonyl compounds

Toward a more efficient use of crude H2 without its energy-consuming purification and/or composition regulation processes, this study employs gaseous mixtures of H2, CO, CO2, and CH4 for the catalytic hydrogenation of aldehydes and ketones in the presence of strategically designed triarylboranes and 4-methyltetrahydropyrane as a greener ethereal solvent. The present results emphasize the unexplored utility of less-toxic main-group catalysis for the catalytic hydrogenation using CO- and CO2-rich crude H2. This stands in contrast to the well-established transition-metal catalysis that generally requires purified H2.

Phosphate-supported palladium single atom and nanoparticle boost ambient temperature tandem hydrogenolysis–hydrogenation of furan alcohols/aldehydes

Developing a one-pot method for tandem hydrogenolysis–hydrogenation of biomass-derived furan-based alcohols to methyltetrahydrofurans is challenging but crucial for synthesizing sustainable biofuels and chemicals. Herein, we report the efficient hydrogenolysis–hydrogenation of furan alcohol to 2-methyltetrahydrofuran using a phosphate-supported synergistic palladium single atom and nanoparticle at an ambient temperature. Comprehensive characterizations and theoretical calculations reveal that in situ H2 heterolysis at the palladium single atom–AlPO4 interface generates frustrated Lewis H+–H− pairs, which selectively cleaves the C–OH bond in furan alcohol to form 2-methylfuran, and H atoms on the palladium nanoparticle surface promotes the subsequent CC hydrogenation of 2-methylfuran to 2-methyltetrahydrofuran. Additionally, the catalyst shows generality for various furan and heterocyclic alcohols. Furthermore, the catalyst exhibits excellent activity in the hydrogenation–hydrogenolysis–hydrogenation of furan aldehydes to methyltetrahydrofurans. The results provide a highly efficient reaction for synthesizing methyltetrahydrofurans at ambient temperature, which has excellent potential for industrial applications.

Ruthenium-Picolylamine-Incorporated Mixed-Linker MOFs: Highly Active Heterogeneous Catalysts for Olefin and Aldehyde Hydrogenation

Ruthenium-Picolylamine-Incorporated Mixed-Linker MOFs: Highly Active Heterogeneous Catalysts for Olefin and Aldehyde Hydrogenation

Cobalt catalyst encapsulated by N-doped carbon for selective hydrogenation of aldehyde to alcohol

Furfuryl alcohol is an important industrial chemical and an intermediate for the synthesis of other high-value products. Here, an explosion-assisted strategy was developed to synthesize nitrogen-doped carbon-encapsulated cobalt nanoparticles catalyst Co-NC. The selective hydrogenation of furfural to furfuryl alcohol can be achieved over Co-NC in aqueous solution successfully. The presence of cobalt nitrate enhanced the explosion process which promoted its decomposition in turn. The high-temperature reduction process accelerated the derivation of carbon nitride into N-containing carbon encapsulating on cobalt nanoparticles. The N-containing coating improves the hydrophilia and catalytic activity of catalyst, thus achieving the selective hydrogenation of aldehydes in aqueous solution.

Multi-scale utilization of lignin: A catalytic hydrogenation strategy based on catechyl lignin nanoparticles

With an abundance of oxygen-containing groups on the hydrophilic shell of lignin nanoparticles (LNPs), this biomaterial can serve as a catalytic support to adsorb and load metals. Herein, catechyl lignin oligomers from castor seed coats (Cas) were extracted via solvothermal pretreatment and prepared as LNPs using the solvent shifting method. Pd2+ ions were then stabilized and reduced in situ on the surface of LNPs, which were further utilized for the catalyzed hydrogenation of lignin-derived aldehydes. Due to the homogeneous building units and linear linkages, the lignin oligomers from Cas exhibited superior self-assembly capacity with a lower π-π interaction energy than those from conventional lignocelluloses, resulting in a high yield of LNPs with a smooth surface. The high content of phenolic hydroxyl groups in catechyl-dominant LNPs resulted in efficient Pd2+ ions adsorption via chemisorption of monomolecular layer and a partial reduction of the Pd2+ ions into metallic states. In addition, the Cas-derived Pd/LNPs exhibited exceptional catalytic activity for the hydrogenation of lignin-derived aldehydes with high selectivity to alcohols under mild conditions. This could be attributed to the interaction preference of the reaction substrate according to the construction of LNPs: strong hydrogen bond between the aldehyde group of the substrate and the hydrophilic shell of LNPs, as well as the hindered π-π interactions between the benzene ring of the substrate and the hidden hydrophobic core of LNPs. This study, therefore, successfully employed lignin with a broad range of molecular weights from oligomers to monomers, paving the way for a comprehensive lignin biorefining industry.

Ethanol as hydrogen donor: An efficient transfer hydrogenation of aldehydes, ketones, and nitroarenes with H-bonded Ru(II)-N-heterocyclic iminium complex

Isopropanol and formic acid are predominantly utilized as hydrogen sources in catalytic transfer hydrogenation reactions. However, the utilization of primary alcohols in such reactions has been sparsely documented, with only a limited number of reports available. In this article, we hereby present findings that underscore the prospective application of ecologically sustainable and economically viable ethanol, alongside a ruthenium(II) catalyst that exhibits remarkable resilience in the presence of moisture and oxygen. The air-stable Ru(II) complex (I) has been synthesized by non-covalently interacting anionic Ru(p-cymene)Cl3 and 1,3-diisopropyl-1H-perimidin-2(3H)-iminium (LH2+). The compound was subjected to experimental evaluation to conduct transfer hydrogenation reactions on aldehydes, ketones, and nitroarenes. The process entailed the utilization of ethanol, a hydrogen source that is both economically advantageous and ecologically benign. The hydrogen bond interaction existing between the Ru(p-cymene)Cl3 and LH2+ species plays a crucial in facilitating the exceptional catalytic efficiency exhibited by the Ru(II) complex (I). The reaction exhibits a wide range of substrate compatibility, enabling the hydrogenation of ketones, aldehydes, and nitroarenes. The results obtained from the control experiments have provided evidence for the formation of Ru − H species. A plausible mechanism has been hypothesized, relying on stoichiometric investigations.

Influence of Glow Discharge Plasma Treatment on Cashew Apple Juice’s Aroma Profile and Volatile Compounds

Cashew apple juice has a distinctive fruity aroma but contains an undesired balsamic/chemical note caused by the high concentration of styrene and other aromatic hydrocarbons. Cold plasma technology can induce chemical changes to fruit juices’ volatile compounds, improving the aroma of fruit juices. This study is aimed at evaluating the chemical effects of cold plasma on the volatile compounds and aroma of cashew apple juice, which is characterized by a complex mixture of compounds. Glow discharge plasma was applied to cashew apple juice, varying the plasma flow rate (10 to 30 mL/min) and processing time (10 to 20 min) at a constant voltage (80 kV). Plasma treatment induced several changes in the juice’s volatile compound composition, with a significant decrease in fatty acids and fatty acid esters (92%) and an increase in aldehydes (50%), alcohols (86%), and short-chain esters (21%). The primary reaction observed during plasma treatment was the internal scission of fatty acid and fatty acid esters, which formed short-chain esters and aldehydes. Further hydrogenation of aldehydes produced alcohols. The chemical changes induced by plasma treatment intensified cashew apple juice’s aroma by 28% while maintaining its aroma profile.

New ruthenium/phosphino carbazole systems for selective preparation of alcohols under hydroformylation conditions

Efficient hydrogenation of aldehydes is highly desirable in hydroformylation process to obtain alcohol products. This work developed carbazole-derived phosphine ligands for efficient Ru-catalyzed hydrogenation of aldehydes in the presence of carbon monoxide. Up to 99 % yields of alcohols were obtained in the presence of high-pressure CO at 130 ℃. The results of different ligands revealed the crucial role of NH moiety on carbazole in promoting the catalytic hydrogenation. It was applied to the Co/Ru-catalyzed hydroformylation process, resulting in the production of long-chain alcohols with excellent yields.

Investigation of Rh/NR3 catalytic systems in sequential stages of reductive hydroformylation engaging in situ X-ray absorption spectroscopy

Nowadays reductive hydroformylation over Rh/NR3 catalysts is of great interest to both industry and academia, however, some of its aspects remain controversial or unclear, including those which might turn essential for developing new active catalysts and optimization of parameters. In this work, we studied in depth separately both stages of the process – hydroformylation of olefins and hydrogenation of aldehydes, – and estimated the role of the amine structure in them. Also, for the first time, we investigated Rh/NR3 catalytic system under the reaction conditions by in situ XAS method to gain the additional structural information, and observed the correlation of the obtained data with the results of catalytic experiments. Catalytic and in situ XAS measurements shown that tertiary amines suppress Rh clusterization, forming species of lower nuclearity. These Rh/amine species may include both charged and uncharged ones. The addition of amines, which are effective promotors of the hydrogenation step, decelerates hydroformylation, presumably, through the formation of amine containing Rh complexes.

Dual-core drive hydrogen transfer heterogeneous catalysts based on iridium-enzyme co-modified carbon nanotubes for aromatic aldehyde hydrogenation

Here, a novel dual-core drive transfer hydrogen heterogeneous catalysts Ir@CNT@ADH were developed by sequentially immobilizing the NADH-dependent alcohol dehydrogenase ADH and high active NADH-regenerated catalyst Pyren-Ir1 on the surface of carbon nanotubes. Two pyrene-functionalized Ir-complex, Pyrene-Ir1 and Pyrene-Ir2, were synthesized and demonstrated exceptional coenzyme NADH generation performances, ensuring continuous in situ NADH generation in the enzyme-catalyzed process. These complexes could be easily modified onto carbon nanotube materials by mild π-π conjugated adsorption. The catalysts Ir@CNT@ADH showed significantly improved catalytic hydrogenation efficiency in the reduction of benzaldehyde to the corresponding alcohol, compared to the single Pyrene-Ir1 modified carbon nanotube catalyst Ir@CNT and homogeneous catalytic system in the presence of a catalytic amount of NAD+. The yield of benzyl alcohol increased by more than 50 % in all cases. We assume that the designed dual-core drive heterogeneous catalyst strategy could effectively address the mutual inactivation problem of enzyme and Iridium complexes by blocking the contact between enzymes with Iridium complexes and enhancing the in situ regeneration property of coenzyme NADH in the enzyme catalytic system. Furthermore, catalyst Ir@CNT@ADH also demonstrated excellent catalytic hydrogeneration performances for various substituted benzaldehyde with good recycling performance. Therefore, the proposed dual-core drive heterogeneous catalyst strategy holds great potential for the combined industrial application of chemical catalysts and bioenzymes. It is expected to contribute to the development and preparation of higher-value biochemical products.

Low‐field 2D NMR relaxometry to disclose the support-substrate interaction and surface dynamics in heterogeneous catalysis: A novel and complementary view to high field NMR relaxometry

This work aims to disclose the support-substrate interaction and surface dynamics in heterogeneous catalysis by an original Low Field 2D NMR relaxation in complement to previous High Field NMR relaxometry. The combination of High Field NMR measurements with the new Low Field 2D NMR results presented in this work confirmed the possibility to extract information on local molecular dynamics and 2D surface dynamics for the complex system of aldehyde hydrogenation on Pd/C catalysts in the presence of a solvent. In particular, here multidimensional Low Field (2D) 1H nuclear magnetic relaxation experiments (T1-T2) have been used to characterize noninvasively the dynamical properties of benzaldehyde, octanal and p-xylene at surfaces of Pd-supported on carbon catalysts. 2D Low Field 1H NMR relaxation is sensitive to the environment of the reactant molecules and gives unambiguous information on the surface dynamics of the molecule; the association with previous 13C NMR relaxation at High Field s allows comparison between molecular orientations and local surface dynamics at surface of catalysts. In heterogeneous catalysis these new experimental and theoretical multiscale approaches link interfacial molecular dynamics and interaction with catalytic materials. This point is critical for disentangle chemical from physical reactant adsorption and deepening the role of the support material and its physical features in catalytic processes.

Study on the Hydrogenation of Ethyl Stearate to the Fatty Alcohol 1-Octadecanol over Ru on Tungstated Zirconia

Fatty alcohols are important products in the chemical industry, given that they are frequently used in the formulation of surfactants and lubricants. In this context, this work describes a catalytic heterogeneous approach for the production of 1-octadecanol (C18OH) from ethyl stearate (ES) using nanosized Ru-supported on tungstated zirconia (W/Zr). The activity and selectivity of this series of catalysts have been studied during the hydrogenation of ES in a batch reactor at 175 °C and PH2 = 40 bar. The so-prepared catalysts were characterized by a sort of characterization techniques (i.e., X-ray diffraction, H2-TPR, etc.), confirming the high dispersion and higher reducibility of Ru nanoparticles on the W/Zr surface (primarily tetragonal zirconia) with respect to pure zirconia. Overall, the catalysts were significantly active. In addition, a strong synergistic effect was revealed between Ru and W species, according to catalytic data. Finally, the reaction sequence towards fatty alcohol has also been elucidated, pointing to the ester hydrogenolysis to the aldehyde and ulterior hydrogenation of the latter as the main route for fatty alcohol formation.

Selective Hydrogenation of Croton Aldehyde on Pt Nanoparticles Controlled by Tailoring Fraction of Well-Ordered Facets Under Different Pretreatment Conditions

Selective Hydrogenation of Croton Aldehyde on Pt Nanoparticles Controlled by Tailoring Fraction of Well-Ordered Facets Under Different Pretreatment Conditions

Halide Adsorption Enhances Electrochemical Hydrogenolysis of 5-Hydroxymethylfurfural by Suppressing Hydrogenation.

Reductive upgrading of 5-hydroxymethylfurfural (HMF), a biomass-derived platform molecule, to 2,5-dimethylfuran (DMF), a biofuel with an energy density 40% greater than that of ethanol, involves hydrogenolysis of both the aldehyde (C═O) and the alcohol (C-OH) groups of HMF. It is known that when hydrogenation of the aldehyde occurs to form 2,5-bis(hydroxymethyl)furan (BHMF), BHMF cannot be further reduced to DMF. Thus, aldehyde hydrogenation must be suppressed to increase the selectivity for DMF production. Previously, it was shown that on a Cu electrode hydrogenolysis occurs mainly through proton-coupled electron transfer (PCET), where a proton from the solution and an electron from the electrode are transferred to the organic species. In contrast, hydrogenation occurs not only through PCET but also through hydrogen atom transfer (HAT), where a surface-adsorbed hydrogen atom (H*) is transferred to the organic species. This study shows that halide adsorption on Cu can effectively suppress HAT by decreasing the steady-state H* coverage on Cu during HMF reduction. As HAT enables only aldehyde hydrogenation, a striking suppression of BHMF is observed, thereby enhancing DMF production. We discuss how the identity and concentration of the halide, along with the reduction conditions (i.e., potential and pH), affect halide adsorption on Cu and identify when optimal halide coverages are achieved to maximize DMF selectivity. Our experimental results are presented alongside computational results that elucidate how halide adsorption affects the adsorption energy of hydrogen and the steady-state H* coverage on Cu, which provide an atomic-level understanding of all experimentally observed effects.

CuCoMgAlOx Mixed Oxides as Selective Catalysts for the Hydrogenation of Furan Compounds

Single phase CuCoMgAl-layered hydroxides were obtained by making fine adjustment to their composition through changing the (Co + Cu)/Mg = 0.5; 1; 2; 3 and Co/Cu = 0.5; 1; 2 ratios. The rise of Co/Cu in systems contributed to the increase in their thermal stability. CuCoMgAl-catalysts showed high selectivity of carbonyl group hydrogenation in furfural and 5-hydroxymethylfurfural. In furfural hydrogenation, the selectivity to furfuryl alcohol was more than 99%, and in 5-hydroxymethylfurfural hydrogenation, the selectivity to 2,5-hydroxymethyl furfural was 95%. The surface of the samples with different Co/Cu after calcination and reduction was the same and had a «core-shell» structure (TEM). «Core» consisted of Cu and Co metallic particles. «Shell» consisted of CuCoMgAlOx mixed no-stoichiometric spinel oxides. There was no sintering or change in size of the metallic particles after the reaction. For the sample with Co/Cu = 1, their phase composition after reaction remained unchangeable. The increase of Co/Cu led to the formation of an X-ray amorphous phase after the reaction. This suggests the decrease in structural stability of this sample. The obtained results prove the prospects of using bimetallic CoCu-systems for hydrogenation of furan aldehydes, and opens up new directions for further research and improvement.

Benzotriazole/indazole-appended phenanthroline-based NNN-tridentate ligand-supported Ru(II) complexes and their application in catalytic transfer hydrogenation

Two discrete Ru(II) complexes [Ru(L1)(bpy)Cl]Cl (Ru-1) and [Ru(L2)(bpy)Cl]Cl (Ru-2) bearing benzotriazole/indazole-appended phenanthroline-based NNN-tridentate ligands L1 and L2 respectively, with one bipyridine and one chloride as co-ligands, were synthesized and characterized fully via spectroscopic and crystallographic techniques. The crystal structures of the complexes revealed the discrete monomeric structures. Both the complexes exhibited MLCT bands in the range of 400–500 nm. The RuII/III redox potential of Ru-1 was found to be more positive (by 155 mV) than that of Ru-2, indicating the stronger π-acceptor property of the ligand L1 than L2. Both the complexes have been found to be efficient precatalysts in transfer hydrogenation of aldehydes and ketones.