Catalytic conversion of nonfood woody biomass solids to organic liquids

Hydrogen-Induced Formation of Surface Acid Sites on Pt/Al(PO3)3 Enables Remarkably Efficient Hydrogenolysis of C-O Bonds in Alcohols and Ethers

The hydrogenolysis of oxygenates such as alcohols and ethers is central to the biomass valorization and also a valuable transformation in organic synthesis. However, a mild and efficient catalyst system for the hydrogenolysis of a large variety of alcohols and ethers with various functional groups is still underdeveloped. Here, we report an aluminum metaphosphate-supported Pt nanoparticles (Pt/Al(PO3)3) for the hydrogenolysis of a wide variety of primary, secondary, and tertiary alkyl and benzylic alcohols, and dialkyl, aryl alkyl, and diaryl ethers, including biomass-derived furanic compounds, under mild conditions (0.1-1 atm of H2, as low as 70 °C). Mechanistic studies suggested that H2 induces formation of the surface Brønsted acid sites via its cleavage by supported Pt nanoparticles. Accordingly, the high efficiency and the wide applicability of the catalyst system are attributed to the activation and cleavage of C-O bonds by the hydrogen-induced Brønsted acid sites with the assistance of Lewis acidic Al sites on the catalyst surface. The high efficiency of the catalyst implies its potential application in energy-efficient biomass valorization or fine chemical synthesis.

Production of Renewable Hydrocarbon Biofuels with Lignocellulose and Its Derivatives over Heterogeneous Catalysts

In recent years, the issues of global warming and CO2 emission reduction have garnered increasing global attention. In the 21st Conference of the Parties (convened in Paris in 2015), 179 nations and the European Union signed a pivotal agreement to limit the global temperature increase of this century to well below 2 K above preindustrial levels. To fulfill this objective, extensive research has been conducted to use renewable energy sources as potential replacements for traditional fossil fuels. Among them, the production of hydrocarbon transportation fuels from CO2-neutral and renewable biomass has proven to be a particularly promising solution due to its compatibility with existing infrastructure. This review systematically summarizes research progress in the synthesis of liquid hydrocarbon biofuels from lignocellulose during the past two decades. Based on the chemical structure (including n-paraffins, iso-paraffins, aromatics, and cycloalkanes) of hydrocarbon transportation fuels, the synthesis pathways of these biofuels are discussed in four separate sections. Furthermore, this review proposes three guiding principles for the design of practical hydrocarbon biofuels, providing insights into future directions for the development of viable biomass-derived liquid fuels.

Recent Advances in Reversible Liquid Organic Hydrogen Carrier Systems: From Hydrogen Carriers to Catalysts

Liquid organic hydrogen carriers (LOHCs) have gained significant attention for large-scale hydrogen storage due to their remarkable gravimetric hydrogen storage capacity (HSC) and compatibility with existing oil and gas transportation networks for long-distance transport. However, the practical application of reversible LOHC systems has been constrained by the intrinsic thermodynamic properties of hydrogen carriers and the performances of associated catalysts in the (de)hydrogenation cycles. To overcome these challenges, thermodynamically favored carriers, high-performance catalysts, and catalytic procedures need to be developed. Here, significant advances in recent years have been summarized, primarily centered on regular LOHC systems catalyzed by homogeneous and heterogeneous catalysts, including dehydrogenative aromatization of cycloalkanes to arenes and N-heterocyclics to N-heteroarenes, as well as reverse hydrogenation processes. Furthermore, with the development of metal complexes for dehydrogenative coupling, a new family of reversible LOHC systems based on alcohols is described that can release H2 under relatively mild conditions. Finally, views on the next steps and challenges in the field of LOHC technology are provided, emphasizing new resources for low-cost hydrogen carriers, high-performance catalysts, catalytic technologies, and application scenarios.

Noninnocent Azo-Aromatic Cobalt(II)-Catalyzed sp3 C-H Alkylation of Fluorenes with Alcohols

Herein, employing well-defined redox noninnocent cobalt(II) complexes an efficient sp3 C-H alkylation of fluorenes using alcohols as alkylating agents to result in alkylated fluorenes is reported. The catalytic protocol was versatile with various fluorenes and benzyl alcohols. It also showed very good functional group tolerance with both alcohols and fluorenes. Moreover, an efficient single-step and simultaneous di C-C as well as both C-C and the C-N alkylation reaction of fluorenes was observed with this catalytic protocol. Such selective single-step dialkylation of fluorenes is indeed beneficial. Several control experiments, deuterium labeling, and 1H NMR kinetic studies have revealed a ligand radical-based borrowing hydrogen mechanism involving the azo-aromatic complexes of cobalt as catalysts for the alkylation of fluorenes.

Well-Defined Mn(II)-complex Catalyzed Switchable De(hydrogenative) Csp3 -H Functionalization of Methyl Heteroarenes: A Sustainable Approach for Diversification of Heterocyclic Motifs

Catalytic activities of Mn(I) complexes derived from expensive MnBr(CO)5 salt have been explored in various dehydrogenative transformations. However, the reactivity and selectivity of inexpensive high spin Mn(II) complexes are uncommon. Herein, we have synthesized four new Mn(II) complexes and explored switchable alkenylation and alkylation of methyl heteroarenes employing a single Mn(II)catalyst. The developed protocol selectively furnishes a series of functionalized E-heteroarenes and C-alkylated heteroarenes with good to excellent yields. Various medicinally and synthetically useful compounds are successfully synthesized using our developed protocol. Various controls and kinetics experiments were executed to shed light on the mechaism,which reveals that α-C-H bond breaking of alcohol is the slowest step.

Advances in Group VI Metal-Catalyzed Homogeneous Hydrogenation and Dehydrogenation Reactions

Transition metal-catalyzed homogeneous hydrogenation and dehydrogenation reactions for attaining plethora of organic scaffolds have evolved as a key domain of research in academia and industry. These protocols are atom-economic, greener, in line with the goal of sustainability, eventually pave the way for numerous novel environmentally benign methodologies. Appealing progress has been achieved in the realm of homogeneous catalysis utilizing noble metals. Owing to their high cost, less abundance along with toxicity issues led the scientific community to search for sustainable alternatives. In this context, earth- abundant base metals have gained substantial attention culminating enormous progress in recent years, predominantly with pincer-type complexes of nickel, cobalt, iron, and manganese. In this regard, group VI chromium, molybdenum and tungsten complexes have been overlooked and remain underdeveloped despite their earth-abundance and bio-compatibility. This review delineates a comprehensive overview in the arena of homogeneously catalysed (de)hydrogenation reactions using group VI base metals chromium, molybdenum, and tungsten till date. Various reactions have been described; hydrogenation, transfer hydrogenation, dehydrogenation, acceptorless dehydrogenative coupling, hydrogen auto transfer, along with their scope and brief mechanistic insights.

Borrowing Hydrogen β-Phosphinomethylation of Alcohols Using Methanol as C1 Source by Pincer Manganese Complex

Herein, we report a manganese-catalyzed three-component coupling of β-H containing alcohols, methanol, and phosphines for the synthesis of γ-hydroxy phosphines via a borrowing hydrogen strategy. In this development, methanol serves as a sustainable C1 source. A variety of aromatic and aliphatic substituted alcohols and phosphines could undergo the dehydrogenative cross-coupling process efficiently and deliver the corresponding β-phosphinomethylated alcohol products in moderate to good yields. Mechanistic studies suggest that this transformation proceeds in a sequential manner including catalytic dehydrogenation, aldol condensation, Michael addition, and catalytic hydrogenation.

N-Alkylation of aromatic amines with alcohols by using a commercially available Ru complex under mild conditions

An N-alkylation procedure has been developed under very mild conditions using a known commercially available Ru-based catalyst. As a result, a wide range of aromatic primary amines has been selectively alkylated with several primary alcohols, yielding the corresponding secondary amines in high yields. The methodology also enables the methylation of anilines in refluxing methanol and the preparation of a set of heterocycles in a straightforward way.

Selective nucleophilic α-C alkylation of phenols with alcohols via Ti=Cα intermediate on anatase TiO2 surface

C-C bond forming reaction by alkylation of aryl rings is a main pillar of chemistry in the production of broad portfolios of chemical products. The dominant mechanism proceeds via electrophilic substitution of secondary and tertiary carbocations over acid catalysts, forming multiple aryl alkylation products non-selectively through all secondary and tertiary carbons in the alkyl chains but producing little α-C alkylation products because primary carbocations are poorly stable. Herein, we report that anatase TiO2 (TiO2-A) catalyzes nucleophilic α-C alkylation of phenols with alcohols in high selectivity to simply linear alkylphenols. Experimental and computational studies reveal the formation of Ti=C- bond with the α-carbon of the alkyl group at oxygen vacancies of the TiO2-A surface. The subsequent α-C alkylation by selective substitution of phenol ortho-C-H bond is verified by deuterium exchanged substrate and DFT calculations.

Synthesis and structure of Pd(II) pincer complexes: catalytic application in β-alkylation of secondary alcohols involving sequential dehydrogenation of alcohols via the borrowing hydrogen approach

Herein, we report an efficient and sustainable approach for the selective synthesis of ketones by palladium pincer catalyzed β-alkylation of secondary alcohols with aromatic primary alcohols via the borrowing hydrogen (BH) approach for the first time. A set of new Pd(II) ONO pincer complexes was synthesized and characterised by elemental analysis and spectral techniques (FT-IR, NMR and HRMS). The solid-state molecular structure of one the complexes was corroborated by X-ray crystallography. A range of α-alkylated ketone derivatives (25 examples) was obtained in excellent yields up to 95% through sequential dehydrogenative coupling of secondary and primary alcohols with 0.5 mol% catalyst loading with a substoichiometric amount of the base. Control experiment studies were carried out for the coupling reactions which revealed that the reaction involves an aldehyde, a ketone and chalcone intermediates, and eventually established the borrowing hydrogen strategy. Gratifyingly, this protocol is simple and atom economical, with water/hydrogen as byproducts. In addition, large-scale synthesis also demonstrated the synthetic usefulness of the present protocol.

Microwave-Assisted Synthesis of E-Aldimines, N-Heterocycles, and H2 by Dehydrogenative Coupling of Benzyl Alcohol and Aniline Derivatives Using CoCl2 as a Catalyst

The acceptorless dehydrogenative coupling (ADC) between alcohols and amines to produce imines has been achieved mostly by employing precious-metal-based complexes or complexes of earth-abundant metal ions with sensitive and complicated ligand systems as catalysts mostly under harsh reaction conditions. Methodologies using readily available earth-abundant metal salts as catalysts without the requirement of ligand, oxidant, or any external additives are not explored. We report an unprecedented microwave-assisted CoCl₂-catalyzed acceptorless dehydrogenative coupling of benzyl alcohol and amine for the synthesis of E-aldimines, N-heterocycles, and H₂ under mild condition, without any complicated exogenous ligand template, oxidant, or other additives. This environmentally benign methodology exhibits broad substrate scope (43 including 7 new products) with fair functional-group tolerance on the aniline ring. Detection of metal-associated intermediate by gas chromatography (GC) and HRMS, H₂ detection by GC, and kinetic isotope effect reveal the mechanism of this CoCl_2-catalyzed reaction to be via ADC. Furthermore, kinetic experiments and Hammett analysis with variation in the nature of substituents over the aniline ring reveal the insight into the reaction mechanism with different substituents.

No Transition Metals Required - Oxygen Promoted Synthesis of Imines from Primary Alcohols and Amines under Ambient Conditions

The synthesis of imines denotes a cornerstone in organic chemistry. The use of alcohols as renewable substituents for carbonyl-functionality represents an attractive opportunity. Consequently, carbonyl moieties can be in situ generated from alcohols upon transition-metal catalysis under inert atmosphere. Alternatively, bases can be utilized under aerobic conditions. In this context, we report the synthesis of imines from benzyl alcohols and anilines, promoted by KOt Bu under aerobic conditions at room temperature, in the absence of any transition-metal catalyst. A detailed investigation of the radical mechanism of the underlying reaction is presented. This reveals a complex reaction network fully supporting the experimental findings.

A Bench-stable 8-Aminoquinoline Derived Phosphine-free Manganese (I)-Catalyst for Environmentally Benign C(α)-Alkylation of Oxindoles with Secondary and Primary Alcohols

Herein, we report a new air-stable phosphine-free 8-AQ (8-aminoquinoline) based Mn(I) carbonyl complex as the catalyst for the C(α)-alkylation of oxindoles with alcohols. The Mn complex [(8-AQ)Mn(CO)₃ Br] works effectively as a catalyst for the α-alkylation of oxindoles by both secondary as well as primary alcohols. The procedure has been used for the synthesis of pharmaceutically important recently developed oxindoles such as 3-(4-methoxybenzyl)indolin-2-one, 3-(4-(dimethylamino)benzyl)indolin-2-one, 3-(4-(dimethylamino)phenyl)-5-fluoroindolin-2-one and 3-(benzo[d][1,3]dioxol-5-ylmethyl)indolin-2-one, which are found to be effective in preventing specific types of cell death in neurodegenerative disorders. Control experiments have been carried out to investigate the reaction mechanism and the crucial role of metal-ligand cooperation via -NH₂ moiety during catalysis.

Manganese-Catalyzed Chemoselective Coupling of Secondary Alcohols, Primary Alcohols and Methanol

Herein, we report a manganese-catalyzed three-component coupling of secondary alcohols, primary alcohols and methanol for the synthesis of β,β-methylated/alkylated secondary alcohols. Using our method, a series of 1-arylethanol, benzyl alcohol derivatives, and methanol undergo sequential coupling efficiently to construct assembled alcohols with high chemoselectivity in moderate to good yields. Mechanistic studies suggest that the reaction proceeds via methylation of a benzylated secondary alcohol intermediate to generate the final product.

N, S Co-Coordinated Zinc Single-Atom Catalysts for N-Alkylation of Aromatic Amines with Alcohols: The Role of S-Doping in the Reaction

S-doping emerged as a promising approach to further improve the catalytic performance of carbon-based materials for organic synthesis. Herein, a facile and gram-scale strategy was developed using zeolitic imidazole frameworks (ZIFs) as a precursor for the fabrication of the ZIF-derived N, S co-doped carbon-supported zinc single-atom catalyst (CNS@Zn₁-AA) via the pyrolysis of S-doped ZIF-8, which was modified by aniline, ammonia and thiourea and prepared by one-pot ball milling at room temperature. This catalyst, in which Zn is dispersed as the single atom, displays superior activity in N-alkylation via the hydrogen-borrowing strategy (120 °C, turnover frequency (TOF) up to 8.4 h^-1). S-doping significantly enhanced the catalytic activity of CNS@Zn₁-AA, as it increased the specific surface area and defects of this material and simultaneously increased the electron density of Zn sites in this catalyst. Furthermore, this catalyst had excellent stability and recyclability, and no obvious loss in activity after eight runs.

Process water recirculation for catalytic hydrothermal carbonization of anaerobic digestate: Water-Energy-Nutrient Nexus

The process water (PW) from acid-catalyzed hydrothermal carbonization (HTC) is still an environmental burden due to the enriched organics, nutrients, and salts. This study proposed a novel strategy to valorize food waste digestate into multifunctional hydrochar by recirculating the PW in the HCl-catalyzed HTC process. The produced multifunctional hydrochar could be utilized as a high-quality solid fuel with HHV of 27.9 MJ kg^-1 (hydrochar without PW recirculation) and a slow-release fertilizer by converting the complex Ca and P compounds from the food waste digestate into a Ca-P deposit (hydroxyapatite) with more than a 93 % P recovery rate (hydrochar with PW recirculation). Adding fresh HCl in the HTC PW recirculation system only displayed a marginal catalytic impact on the hydrochar properties after two cycles of recirculation. This study demonstrated the importance of inherent Ca in the feedstocks and the dual role of HCl in the HTC with PW recirculation.

Superhydrophobic Ru Catalyst for Highly Efficient Hydrogenation of Phenol under Mild Aqueous Conditions

Selective hydrogenations of lignin-derived phenolic compounds represent essential processes in the chemical industry, especially for production of a multitude of fine chemicals. However, selective hydrogenation of phenolic compounds in water phase suffers from low conversion. Here we report a catalyst of well-dispersed Ru clusters fixed in N-doped mesoporous hollow carbon spheres (Ru@N-CS) for enhanced cyclohexanol productivity in phenol hydrogenation at mild aqueous condition. This superhydrophobicity carbon spheres appear to selectively allow diffusion of phenol and hydrogen molecules to the electron-rich coordination unsaturated Ru active sites, while confining the reactants there to enhance its reaction probability. The Ru@N-CS catalyst can selectively hydrogenate phenol at 80 °C and 0.5 MPa of H2 in 30 min in aqueous medium with phenol conversions of 100% and ~100% cyclohexanol selectivity, corresponding to cyclohexanol productivity up to 471 per g of Ru per minute. The TOF value is up to 9980 h−1, which 14 times more than Ru nanoparticles supported on N-doped carbon hollow spheres (Ru/N-CS). This work provides an important catalytic system for upgrading of bio-oil into value-added chemicals under mild aqueous-phase.

Interception of Nickel Hydride Species and Its Application in Multicomponent Reactions

The hydrogen borrowing strategy is an economical method for the α-functionalization of ketones. While this strategy is extremely advantageous, it does not lend itself to the synthesis of β,β-disubstituted ketones. This can be achieved, if the in situ generated metal hydride can be intercepted with a nucleophilic coupling partner. We present a multicomponent strategy for the coupling of alcohols, ketones, and boronic acids using only 1 mol % nickel catalyst and without the need for added ligands.

Selective modification of hydroxyl groups in lignin model compounds by ruthenium-catalyzed transfer hydrogenation

Selective ruthenium-catalyzed oxidation of lignin diol model compounds and lignin was accomplished by a transfer hydrogenation methodology. The developed procedure allows us to selectively oxidize benzylic secondary alcohols in model diols and spruce milled wood lignin in the presence of a commercially available Shvo catalyst under aerobic conditions. Six ketoalcohols were obtained in 70-92% yields from the model compounds, which also included lignin monomers containing 5-5' and β-O-4 linkages. The developed method can be used as an intermediate step for the introduction of new functional groups into lignin-type structures and lignin to allow their further modifications.

Ru Doped Hydrotalcite Catalyzed Borrowing Hydrogen-Mediated N-Alkylation of Benzamides, Sulfonamides, and Dehydrogenative Synthesis of Quinazolinones

An efficient Ru doped hydrotalcite catalyzed N-alkylation of benzamides and sulfonamides with alcohols via borrowing hydrogen catalysis is illustrated. Various primary alcohols, including benzyl, heteroaryl, and aliphatic alcohols, were alkylated in good to excellent yields. To shed light on the mechanistic details, several control studies and deuterium labeling experiments were performed. Mechanistic studies underpin that the reaction is going via a borrowing hydrogen pathway rather than an S_N1 type mechanism. The reaction can be easily scaled up without any detrimental effect on the yield. The catalyst is also capable of synthesizing quinazolinone directly from 2-aminobenzamide and alcohols. Successful recyclability and high reactivity highlight the practical applicability of the catalyst.

Well-defined manganese complex catalyzed dehydrogenative synthesis of quinazolin-4(3H)-ones and 3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxides

The synthesis of N-heterocycles has been considered an emerging topic of chemical research due to its widespread usage in medicinal chemistry, materials science, and natural product synthesis.

Synthesis of renewable diesel and jet fuel range alkanes using 2-methylfuran and cyclohexanone

New solid acid catalysts were prepared by bisphenol A, paraformaldehyde and chlorosulfonic acid, and applied to hydroxylalkylation/alkylation (HAA) of 2-methylfuran (2-MF) and cyclohexanone. After optimizing the reaction conditions, the conversion of 2-MF reached 99% and the yield of 5,5′-(cyclohexane-1,1-diyl)bis(2-methylfuran) acquired 98%. The activity and catalytic efficiency were higher than those of Amberlyst 15 and Amberlyst 36 resins, which could be rationalized by high acid strength. At the same time, the catalysts were characterized by acid–base titration and FTIR. Hydrodeoxygenation (HDO) of HAA products of 2-methylfuran and cyclopentanone were processed on the Ni/SiO₂ catalyst prepared by wet impregnation method to further convert into aviation kerosene, and the yield reached 93%.

New solid acid catalysts were prepared by bisphenol A, paraformaldehyde, and applied to HAA of 2-methylfuran (2-MF) and cyclohexanone. Hydrodeoxygenation (HDO) of HAA products of 2-MF and cyclopentanone were processed on Ni/SiO₂ catalyst.

Primary amines from lignocellulose by direct amination of alcohol intermediates, catalyzed by RANEY® Ni

Primary amines are crucially important building blocks for the synthesis of a wide range of industrially relevant products. Our comprehensive catalytic strategy presented here allows diverse primary amines from lignocellulosic biomass to be sourced in a straightforward manner and with minimal purification effort. The core of the methodology is the efficient RANEY® Ni-catalyzed hydrogen-borrowing amination (with ammonia) of the alcohol intermediates, namely alkyl-phenol derivatives as well as aliphatic alcohols, obtained through the two-stage LignoFlex process. Hereby the first stage entails the copper-doped porous metal oxide (Cu20PMO) catalyzed reductive catalytic fractionation (RCF) of pine lignocellulose into a crude bio-oil, rich in dihydroconiferyl alcohol (1G), which could be converted into dihydroconiferyl amine (1G amine) in high selectivity using ammonia gas, by applying our selective amination protocol. Notably also, the crude RCF-oil directly afforded 1G amine in a high 4.6 wt% isolated yield (based on lignin content). Finally it was also shown that the here developed Ni-catalysed heterogeneous catalytic procedure was equally capable of transforming a range of aliphatic linear/cyclic primary/secondary alcohols – available from the second stage of the LignoFlex procedure – into their respective primary amines.

A highly efficient RANEY® Ni-based amination methodology using ammonia that is capable of converting lignocellulose-derived alcohol intermediates into their corresponding primary amines in high selectivity, following hydrogen borrowing methodology.

A review of sustainable biodiesel production using biomass derived heterogeneous catalysts

The production of biodiesel through chemical production processes of transesterification reaction depends on suitable catalysts to hasten the chemical reactions. Therefore, the initial selection of catalysts is critical although it is also dependent on the quantity of free fatty acids in a given sample of oil. Earlier forms of biodiesel production processes relied on homogeneous catalysts, which have undesirable effects such as toxicity, high flammability, corrosion, by-products such as soap and glycerol, and high wastewater. Heterogeneous catalysts overcome most of these problems. Recent developments involve novel approaches using biomass and bio-waste resource derived heterogeneous catalysts. These catalysts are renewable, non-toxic, reusable, offer high catalytic activity and stability in both acidic and base conditions, and show high tolerance properties to water. This review work critically reviews biomass-based heterogeneous catalysts, especially those utilized in sustainable production of biofuel and biodiesel. This review examines the sustainability of these catalysts in literature in terms of small-scale laboratory and industrial applications in large-scale biodiesel and biofuel production. Furthermore, this work will critically review natural heterogeneous biomass waste and bio-waste catalysts in relation to upcoming nanotechnologies. Finally, this work will review the gaps identified in the literature for heterogeneous catalysts derived from biomass and other biocatalysts with a view to identifying future prospects for heterogeneous catalysts.

pH-Mediated Selective Synthesis of N-Allylic Alkylation or N-Alkylation Amines with Allylic Alcohols via an Iridium Catalyst in Water

Amination of allylic alcohols is an effective approach in the facile synthesis of N-allylic alkylation or N-alkylation amines. Recently, a series of catalysts were devised to push forward this transformation. However, current synthetic methods are typically limited to achieve either N-allylic alkylation or N-alkylation products via a certain catalyst. In this article, a pH-mediated selective synthesis of N-allylic alkylation or N-alkylation amines with allylic alcohols via an iridium catalyst with water as the environmental benign solvent is revealed, enabling the miscellaneous synthesis of N-allylic alkylation and N-alkylation products in outstanding yields. Furthermore, a gram-scale experiment with low catalyst loading offers the potential to access a distinct entry for the synthesis of the antifungal drug naftifine.

Manganese catalyzed switchable C-alkylation/alkenylation of fluorenes and indene with alcohols

The usage of earth-abundant, nontoxic transition metals in place of rare noble metals is a central goal in catalysis. This would be especially interesting when the reactivity and selectivity patterns can be tuned. Herein, we introduced the first Mn-catalyzed selective C-alkylation and olefination of fluorene, and indene with alcohols. Various substrates including benzylic, heteroaromatic, and aliphatic primary and secondary alcohols are employed as alkylating agents. Mechanistic investigations and a kinetic study underpin the involvement of the olefinated intermediate to furnish the alkylated product.

Implication of Wood-Derived Hierarchical Carbon Nanotubes for Micronutrient Delivery and Crop Biofortification

A similarity of metal alloy encapsulation with the micronutrient loading in carbon nanoarchitecture can be fueled by exploring carbon nanocarriers to load micronutrient and controlled delivery for crop biofortification. A wood-derived nanoarchitecture model contains a few-graphene-layer that holds infiltrated alloy nanoparticles. Such wood-driven carbonized framework materials with legions of open porous architectures and minimized-tortuosity units further decorated carbon nanotubes (CNTs), which originate from heat treatment to carbonized wood samples. These wood-derived samples can alleviate micronutrient nanoparticle permeation and delivery to the soil. A rapid heat shock treatment can help in distributing N-C-NiFe metal alloy encapsulation in carbon frameworks uniformly in that case; higher heating and rapid extinction of heat shock have led to formation of good dispersion of nanoparticles. The wood-carbon framework decorated with metal alloys displays promising electrocatalytic features and cyclic stability for hydrogen evolution. Envisaged from this strategy, we obtain enough evidence to form an opinion that a singular heat shock process can even lead to a strategy of faster growth of a wood-carbon network with well-dispersed micronutrient metal salts in porous matrices for high-efficiency delivery to the soil. Having envisaged the formation of ultrafine nanoparticles with a good dispersion profile in the case of transition metals and alloy encapsulation in the carbon network due to the rapid heating and quenching rates, we anticipate that the loading of micronutrients in the wood-derived nanoarchitecture of carbonized wood derived carbon nanotube (CW-CNT), which can offer an application in seed germination and enhance growth rates of crops. The experience of controlled experiments on germination of tomato seeds on a medium containing CW-CNT that can diffuse the seed coat with the promotion of water uptake inside seeds for enhanced germination and growth of tomato seedlings can be further extended to cereal crops.

First-Row Transition-Metal Catalyzed Acceptorless Dehydrogenation and Related Reactions: A Personal Account

The development of sustainable catalytic protocols that circumvent the use of expensive and precious metal catalysts and avoid toxic reagents plays a crucial role in organic synthesis. Indeed, the direct employment of simple and abundantly available feedstock chemicals as the starting materials broadens their synthetic application in contemporary research. In particular, the transition metal-catalyzed diversification of alcohols with various nucleophilic partners to construct a wide range of building blocks is a powerful and highly desirable methodology. Moreover, the replacement of precious metal catalysts by non-precious and less toxic metals for selective transformations is one of the main goals and has been paid significant attention to in modern chemistry. In view of this, the first-row transition metal catalysts find extensive applications in various synthetic transformations such as catalytic hydrogenation, dehydrogenation, and related reactions. Herein, we have disclosed our recent developments on the base-metal catalysis such as Mn, Fe, Co, and Ni for the acceptorless dehydrogenation reactions and its application in the C-C and C-N bond formation via hydrogen auto-transfer (HA) and acceptorless dehydrogenation coupling (ADC) reactions. These HA/ADC protocols employ alcohol as alkylating agents and eliminate water and/or hydrogen gas as by-products, representing highly atom-efficient and environmentally benign reactions. Furthermore, diverse simple to complex organic molecules synthesis by C-C and C-N bond formation using feedstock alcohols are also overviewed. Overall, this account deals with the contribution and development of efficient and novel homogeneous as well as heterogeneous base-metal catalysts for sustainable chemical synthesis.

Could preoxidation always promote the subsequent hydroconversion of lignin? Two counterexamples catalyzed by Cu/CuMgAlOx in supercritical ethanol

In this study, two counterexamples of lignin preoxidation-hydroconversion were reported. First, two lignin feedstocks were preoxidized with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in acetonitrile with various dosages (15%, 30%, and 60%). Then, these preoxidized lignins (HELOs and MWLOs) were hydroconverted in supercritical ethanol catalyzed by Cu/CuMgAlO_x. Total yields from HELOs were all higher than those from HEL, indicating the good promotion of DDQ preoxidation on the subsequent hydroconversion of HELOs, especially with the DDQ dosage of 15%. Differently, the promotion effect of DDQ preoxidation on the hydroconversion of MWLOs depended on the DDQ dosage as well as the reaction time. Through the comparison of two counterexamples, this work bursted the myth that preoxidation can always promote the subsequent hydroconversion of lignin, revealed the influence of lignin property, preoxidation degree, and reaction conditions on the subsequent hydroconversion of preoxidized lignin, and presented the new insight into the preoxidation-hydroconversion strategy for lignin.

Efficient Palladium-Catalyzed Carbonylation of 1,3-Dienes: Selective Synthesis of Adipates and Other Aliphatic Diesters

The dicarbonylation of 1,3‐butadiene to adipic acid derivatives offers the potential for a more cost‐efficient and environmentally benign industrial process. However, the complex reaction network of regioisomeric carbonylation and isomerization pathways, make a selective and direct transformation particularly difficult. Here, we report surprising solvent effects on this palladium‐catalysed process in the presence of 1,2‐bis‐di‐tert‐butylphosphin‐oxylene (dtbpx) ligands, which allow adipate diester formation from 1,3‐butadiene, carbon monoxide, and methanol with 97 % selectivity and 100 % atom‐economy under scalable conditions. Under optimal conditions a variety of di‐ and triesters from 1,2‐ and 1,3‐dienes can be obtained in good to excellent yields.