ISSN / EISSN : 1463-9262 / 1463-9270
Published by: The Royal Society of Chemistry (10.1039)
Total articles ≅ 9,751
Latest articles in this journal
Green Chemistry; https://doi.org/10.1039/d1gc03014k
Herein we propose the utilization of nanosized water domain for photocatalytic CO2 conversion, by which CO2 can be efficiently reduced to CO with CO evolution rate of 682 µmol g-1 h-1 and selectivity >99%. It provides a facile, efficient and adjustable route for the photocatalytic CO2 conversion with water.
Green Chemistry; https://doi.org/10.1039/d1gc03205d
Resource shortage and environmental degradation have forced people to pay attention to the development and application of environmentally friendly production method. Alkali/urea is a green water-based solvent for chitin and chitosan, and has been widely used in structural analysis and functional material preparation in recent years. This review systematically summarizes the discovery, improvement and promotion of alkali-soluble systems and expounds its dissolution mechanism for chitin and chitosan in first section. As the core content, we focused on the application of alkali/urea dissolution systems such as NaOH/urea, KOH/urea and KOH/LiOH/urea in the homogeneous chemical modification of chitin and chitosan. The dissolved chitosan and chitin ensure the uniformity and high efficiency of the chemical modification reaction and avoid the participation of high temperature, organic dispersant, alkali swelling and other auxiliary reaction conditions. Moreover, the prepared alkylation, quaternization, carboxylation, acrylamidation derivatives exhibits novel structures and functional characteristics and have been applied in antibacterial, tissue engineering repair, drug delivery, 3D cell culture, bioimaging, wastewater remediation and other fields. We envision that this review will provide a new inspiration and ideas for the improvement of the alkali/urea dissolution system and its application in other fields.
Green Chemistry; https://doi.org/10.1039/d1gc02540f
Synthetic textiles have offered a chance to enhance the life quality since their invention. Nonetheless, the massive generation/accumulation of synthetic textile waste (STW) has indeed posed numerous environmental problems. To offer a strategic disposal platform to valorize STW into flammable gas, the thermo-chemical process of STW was studied in this work. Pyrolysis of STW was particularly studied using CO2 as a raw material to produce more syngas (H2 and CO). To this end, prior to the pyrolysis test, the main constituents in STW were determined as nylon 6. This study also reported that a monomer of nylon 6 (caprolactam) could be recovered from pyrolysis of STW. However, separation of caprolactam could be challenging considering the complex compositional matrixes of STW pyrolytic oil. To enhance the formation of CO stemmed from CO2, catalytic pyrolysis of STW over Ni/SiO2 was tested. The catalytic capability of Ni-based catalyst led to the enhanced conversion of CO2 into CO in line with H2 production and degradation of pyrolytic oil. The production of syngas from CO2-assisted catalytic pyrolysis was 7 times larger than the reference one arising from increased CO formation by catalytic reaction of CO2 with pyrolytic products over catalyst. CO2 also offered a great chance to suppress catalyst deactivation by suppression of coke deposition or removal of coke deposited on catalyst surface. All experimental findings of this study could offer an effective guideline for a thermo-chemical disposal platform for nylon while mitigating a hazardous potential in our ecosystem.
Green Chemistry; https://doi.org/10.1039/d1gc03187b
Herein, the electrochemically driven, Rh(III)-catalyzed regioselective annulations of arenes with alkynes have been established. The strategy combined by rhodium catalyst with electricity not only avoids the need for stoichiometric amount of external oxidant, but also ensures the transformations under mild and green conditions , which enables a broad functional group compatibility with a variety of substrates including drugs and pharmaceutical motifs. Moreover, the electrolysis reaction is operationally simple by employing the undivided cell, and proceeds efficiently in an aqueous solution under an air atmosphere.
Green Chemistry; https://doi.org/10.1039/d1gc02728j
Acetic acid is an important commodity chemical which is produced either by fermentation processes, or more commonly, from chemical routes such as methanol carbonylation with CO and H2, acetaldehyde oxidation, or hydrocarbon oxidation. More recently, methanol hydrocarboxylation with CO2 and H2 under thermal catalytic conditions has attracted interest. The synthesis of acetic acid from easily available CO2 is of great significance yet rarely reported. The present paper describes the first photocatalytic approach for the synthesis of acetic acid from methanol and CO2 under ambient reaction conditions without using molecular hydrogen. The maximum conversion of methanol achieved is 60% with selectivity towards acetic acid of 81% using octa-sulfur bound cobalt phthalocyanine (CoPc/S8) photocatalyst without additional sacrificial electron donor. Product analysis and controlled experiments suggest the formation of carbene as a reactive intermediate. The developed methodology represents a potentially exciting approach for synthesizing acetic acid utilizing CO2 in a sustainable manner.
Green Chemistry; https://doi.org/10.1039/d1gc02922c
An unprecedented metal-/external-oxidant-free electrochemical intermolecular [3+2] heteroannulation of anilines with electron-deficient pyridines enabled by dual C-H radical aminations for producing functionally diverse benzo[4,5]imidazo[1,2-a]pyridines is described. The site-selectivity of aminations of aryl C(sp2)-H bonds relies on the electronic effect of two reaction partners: each contributed two reactive sites (a C(sp2)-H bond and a nitrogen atom-based functional group) and the electron-withdrawing groups at the 4 position of the pyridine ring are crucial. Mechanistic studies show that this method sequence consists of the generation of the nitrogen-centered radical (NCR) and the pyridine radical anion, radical coupling and dual C-N aminations.
Green Chemistry; https://doi.org/10.1039/d1gc02805g
A synergistic combination of photoredox and polarity reversal catalysis enabled a hydrogen evolution cross-coupling of silanes with H2O, alcohols, phenols, and silanols, which afforded the corresponding silanols, monosilyl ethers, and disilyl ethers respectively in moderate to excellent yields. The dehydrogenative cross-coupling of Si−H and O−H proceeded smoothly with broad substrate scope and good functional group compatibility in the presence of only an organophotocatalyst 4-CzIPN and a thiol HAT catalyst, without the requirements of any metals, external oxidants and proton reductants, which is distinct from the previously reported photocatalytic hydrogen evolution cross-coupling reactions where a proton reduction cocatalyst such as a cobalt complex is generally required. Mechanistically, a silyl cation intermediate is generated to facilitate the cross-coupling reaction, which therefore represents an unprecedented approach for the generation of silyl cation via visible-light photoredox catalysis.
Green Chemistry; https://doi.org/10.1039/d1gc02744a
Lignin is one of the most abundant natural polymers. Produced as a by-product from the biomass refinery industries, lignin remains largely underutilised in high-value industrial applications. The incorporation of lignin in rigid polyurethane foam (RPUF) has been the focus of much research, due to its potential to replace fossil fuel-based components of RPUF. However, the overall sustainability of RPUF depends on numerous factors including processability, cost-effectiveness, and retention of performance throughout the foam’s service life. To date, the incorporation of lignin has been explored either as filler particles (through direct incorporation) or as a blendable liquid polyol introduced after chemical modifications (such as oxyalkylation, functionalisation, or depolymerisation). However, the production of lignin incorporated foams possessing both high performance and cost-effective remains an ongoing challenge. Herein, this review critically appraises the progress on the effective incorporation of lignin in RPUF. Firstly, this review briefly covers the essential raw materials, formulation, important properties, and sustainability aspects of RPUF for industrial applications. Secondly, it provides insights on the key parameters of lignin relevant to its effective incorporation into RPUF. Thirdly, it benchmarks the reported studies on incorporation of lignin in RPUF systems by evaluating their important properties and proposes potential strategies for addressing the key challenges in the incorporation of lignin in RPUF. By bridging the gaps that exist in the literature on the utilisation of lignin in RPUF this account will serve as a resource for the successful development of lignin incorporated RPUF for industrial applications.
Green Chemistry; https://doi.org/10.1039/d1gc03145g
This perspective reviews the current status and prospects of biocatalysis in ionic liquids. Although they are not strictly speaking ionic liquids, deep eutectic solvents are included because of the close similarities of their properties and potential applications with those of ionic liquids. One consequence of the ongoing transition from an economy based on fossil resources to a circular economy based on renewable biomass is the burgeoning interest in the use of biocatalysis for the selective conversion of carbohydrates and triglycerides to liquid fuels and chemicals in biorefineries. The use of inexpensive, environmentally attractive ionic liquids as solvents, in the pre-treatment and subsequent biocatalytic conversions, for example, is expected to play an important enabling role in this process
Green Chemistry; https://doi.org/10.1039/d1gc02392f
Nano-micelles meet biogenic Pd nanoparticles at the cell membrane promoting Suzuki Miyaura coupling reactions under mild conditions.