Themed collection 2020 Green Chemistry Hot Articles

Applications of photocatalytic Hydrogen Atom Transfer (HAT) methodologies for the Late-Stage Functionalization (LSF) of complex molecules have been discussed in this perspective.

This article mainly reviews the state-of-the-art achievements of supported metal catalysts and the characteristics and actions of their active sites, working in the reactions involved in HDO of lignin-derived phenolic compounds.

This critical review highlights the recent advancements of using biocompatible ionic liquids as “green” designer solvents and/or materials to overcome the limitations caused by conventional organic solvents/materials in pharmaceutics and medicine.

Main DSSC components, along with their most critical materials and related issues are reviewed and feasible alternatives are envisaged.

Accelerated ageing reactions proceed spontaneously in mixtures of solid reactants, and provide a route towards developing solvent- and energy-free chemistry.

Catalytic C(sp³)–F formation processes are critically reviewed, highlighting recent achievements and pertaining challenges still present in the field.

A perspective on the development of coordination polymers based on sustainable benign ligands and metals, and green synthesis.

This review describes the state-of-the-art of metal-catalyzed selective transfer hydrogenation of α,β-unsaturated aldehydes and ketones to the allylic alcohols, covering the literature of the last 30 years.

A bromide additive is found to be the key for the success of atom-economical photoredox neutral Minisci hydroxyalkylations.

The pathway, glycolaldehyde (C2) → erythrose (C4) → lactic acid (C3) was exploited over the Sn-beta catalyst from xylose.

The first Rh(I)-catalyzed regioselective arylcarboxylation of electron-deficient acrylamides with arylboronic acids under atmospheric pressure of CO₂ has been developed.

The combination of CeO₂ and H-FAU zeolite acted as an effective heterogeneous catalyst for the direct synthesis of diethyl carbonate from CO₂ and ethanol with 2,2-diethoxypropane as a dehydrating agent.

The metal-free benzannulation reactions of alkyl propiolates and aryl enals have been developed for biaryl and atropisomeric biaryl aldehyde synthesis.

Homogeneous catalyzed hydrogenation of furanic aldehydes to their corresponding alcohols using PNP complexes.

Novel photoinduced catalyst-free deborylation–deuteration of arylboronic acids with D₂O under mild conditions is reported. A wide range of deuterated products were obtained in good yields with a high level of deuteration.

Electrosynthesis provides access to substituted adipic acids using lignin-derived cyclohexanols.

Visible-light-mediated regioselective carbocarboxylation of styrenes using CO₂ and amines to generate important γ-amino acids has been realized by photocatalysis.

The biomass feedstock ethyl lactate has been utilized for quinoline synthesis via three-component reactions with anilines and aldehydes. The reactions take place efficiently via oxidant-/solvent-free EL dehydrogenation, and provide only water and hydrogen by-products.

α-Amino cyclic boronates were synthesized from readily available salicylaldehydes, amines, and B₂(OH)₄. The process can be run at room temperature in ethanol, does not require catalysts or additives, and scale up and purification are easy.

The combination of the Williamson and Tishchenko reactions produced a series of new α,ω-diene functionalized carboxylic ester, by which serials of polyesters have been prepared successfully.

A closed loop of recovering rare-earth elements and transition metals from Nd–Fe–B magnets with the total re-use of the electrolyte using a facile electrolysis-selective precipitation procedure.

A convenient and efficient α-allylation of N-aryl tetrahydroisoquinolines has been achieved. This transformation can be realized under only visible light irradiation without the aid of transition metals or photocatalysts.

Sophorolipids are one of the most important microbial biosurfactants, because of their large-scale production and applications developed so far in the fields of detergency, microbiology, cosmetics or environmental science.

Efficient polymerization catalyses transform bio-sourced monomers into thermoplastics with high elasticity and strength, which can be degraded to allow for chemical recycling. The plastics utilize carbon dioxide, limonene oxide and ε-decalactone.

An alkali and cyanide free approach for the synthesis of α-iminonitriles via a base-mediated and 1,3-diketone-catalyzed reaction is reported. The preparation of target compounds was realized by use of nitromethane as solvent and cyanating agent, offering a greener process.

This research work applied the hydrothermal process for the surface treatment of ceramic fibres in replacement of conventional process using strong acids.

Toluene-2,4-diamine, 4,4′-methylenedianiline and 2,4-diaminomesitylene were converted directly into the corresponding dicarbamates via the CO₂-based intermediate methyl formate (MF) which can be regarded as a liquid source for CO/MeOH mixtures.

In presence of a solid acid H-Beta zeolite and Pd/C catalyst, citric acid was converted to tricarballylic acid via a one-pot sequential dehydration-hydrogenation process with a yield up to 85% and a selectivity exceeding 90%.

We have developed a novel N,N′-bis(imidazolyl)guanidine-based system, which shows high performance in low-concentration CO₂ capture and subsequent catalytic transformation to functionalized (4E,5Z)-4-imino-5-benzylideneoxazolidine-2-ones.

A near-neutral waterborne cationic polyurethane from CO₂-polyol was synthesized using BDE as an internal emulsifier. Its compatibility with an aqueous cPANI dispersion and strong adhesion to CS plates mean it could be used for corrosion protection.

Cadaverine is an important monomer used for the production of bio-polyamides. Based on the genome-scale metabolic model of type II methanotroph, iMsOB3b1_cadaverine, we engineered Methylosinus trichosporium OB3b to produce cadaverine from methane.

New coarse-grained models for imidazolium-based ionic liquids (ILs) were developed using the Martini force field. They were able to not only reproduce the structural properties but also allow simulations of liquid–liquid extraction experiments.

A sustainable, economical and convenient one-step process to produce high-value chitin oligomers and digestible shell residue from shrimp shell waste by a chitinase fused to a carbohydrate-binding module.

Four renewable HBS were chosen as co-solvents to promote the selective removal of lignin by increasing the total number of hydrogen bonds.

The integration of biorefining and photocatalysis is the most promising approach to enable green and efficient synthesis of biomass-based high value chemicals.

Textbook catalytic hydrogenations are typically presented as reactions done in organic solvents and oftentimes under varying pressures of hydrogen using specialized equipment.

We demonstrate the electrochemical oxidation of an anthracene derivative to a redox-active anthraquinone at room temperature in a flow cell without the use of hazardous oxidants or noble metal catalysts.

The holistic application of Green Chemistry principles in the design and synthesis of the new broad-spectrum fungicide, florylpicoxamid, is described.

“Trash to treasure”: degraded solid oxide fuel cells can be “revitalized” as high-performance bifunctional catalysts.

Conventional electrically in-series thermogalvanic cells are proven options to chemically convert waste heat into electricity, but often utilise incompatible chemicals. This work reports significantly safer and more robust cell chemistry.

We developed a Life Cycle based Alternatives Assessment (LCAA) framework for efficiently including quantitative exposure and life cycle impacts in chemical substitution studies.

Shake, Rattle and Gold! Mechanochemistry enables the efficient and selective synthesis of organo-Au(I) complexes.

As an alternative to the traditional chemical synthesis or in vivo production of L-pipecolic acid, we have developed two ex vivo strategies using purified and immobilised enzymes for the production of this key building block.

General and high-yielding synthesis of phosphorotrithioites and phosphorotrithioates involving white phosphorus (P₄) and thiols under air conditions is presented.

Efficient selective hydrogenation of furfural to tetrahydrofurfural or 5-hydroxymethylfurfural to 5-hydroxymethyltetrahydro-2-furaldehyde have been realized over Pd/LDH-MgAl-NO₃, and the selectivities could reach 92.6% and 83.7%, respectively.

From alkenes and nitromethane, a cyanide-free pathway to synthesize chiral β-hydroxy nitriles via the enantioselective ring-opening of 5-sub-4,5-dihydroisoxazoles catalyzed by aldoxime dehydratases has been developed.

Coupling biowaste gas recovery with single cell protein production could foster future food safety and sustainability on a global scale.

Proof of concept to interpret the effect of ultrasonication when applied to improve the selective oxidation of aromatic alcohols through heterogeneous photocatalysis.

An efficient photoredox-catalyzed ketyl–ynamide coupling of alkyl sulfonyl substituted ynamides followed by 1,3-allylic alcohol transposition in one-pot has been developed, affording 2-hydroxymethylindoles in generally moderate to good yields.

Multifunctional silacyclopropanes act as universal crosslinkers for PDMS-elastomers, which can react via ring-opening or silylene insertion.

A degradable and recyclable thermoset hyperbranched epoxy resin was synthesized from bio-based 2,5-furandicarboxylic acid.

Macroalgae are a valuable energy source that can be transformed into numerous products most notably fuels and chemicals due to their high content of carbohydrates, proteins, and vitamins.

1,3-Pentadiene (piperylene) is an important monomer in the manufacturing of adhesives, plastics, and resins. This study utilizes fundamental insights gained from the dehydra-decyclization of biomass-derived 2-methyltetrahydrofuran to achieve high piperylene yields.

Cellulose-derived carbon supported Pt nanocatalyst can realize the reductive heterocyclization of 2-nitroacylarenes to 2,1-benzisoxazoles and the amination of levulinic acid to pyrrolidones in the presence of H₂ under ambient conditions.

Iridium catalysed acceptorless dehydrogenative decarbonylation of organosolv lignin is exemplified for the combined lignin defunctionalisation and liberation of synthesis gas.

Photocatalytic deoxygenation of aromatic ketones to alkyl arenes was developed on Pd/TiO₂ using alcohols as green hydrogen donors.

The electrochemical method for gold extraction from multi-metal industrial solutions in an environmentally benign and energy efficient manner is explained in detail.

Schreiner's thiourea activating aldehydes in photochemical reactions.

A green and highly efficient oxidation of alcohols to carboxylic acids using a polyoxometalate-supported chromium(III) catalyst and CO₂.

High stability and outstanding catalytic performance of Mg–Zr/MFI(NS) for the conversion of ethanol and acetaldehyde to butadiene.

An integrated experimental and computational study to understand the catalytic upgrading of biomass vapors into high yield of alkenes.

A mixed metal compound from separation and processing of spent batteries is demonstrated to be feasible as a “second-life” anode.

Bio-based and low-cost hybrid alginate–protein cryogel beads, which can be regenerated and reused, are efficient adsorbent materials for the purification of IgG from human serum.

Nanoporous carbon (nC), as electricity source, is prepared from low-grade tree-gum wastes via carbonization and exfoliation.

A more sustainable and easier applicable synthesis of aliphatic isocyanides in DMC is introduced using non-hazardous p-toluenesulfonyl chloride as dehydration reagent.

Aqueous electrocatalytic alkylation of amines with alcohol; water is the only byproduct.