Search

This review article provides a thorough overview of barrier coating materials that have been used in food packaging with a focus on biodegradable (bio-based or petroleum-based) materials, such as lipids, proteins, polysaccharides, agriculture waste and polyesters. The goal is to provide an opportunity to acknowledge progress made in this field, focusing on modifications made to coatings. These modifications aim to address the shortcomings of biodegradable substrates (either plastic or paper) and improve their performance, enabling them to compete with traditional petroleum-based food packaging materials. This includes their barrier against water vapor and oxygen, mechanical and surface characteristics (sealability and adhesion), as well as antimicrobial properties. The barrier of most biodegradable polymers underperforms in comparison with petroleum-based non-biodegradable polymers, which possess either high water vapor barrier or high oxygen barrier. Coating technology is a promising solution particularly in barrier improvement of biodegradable polymers. Currently, there are only metallized, or inorganic nanosheet coatings available for biodegradable films that meet food packaging requirements. There are some challenges in this field, for example, being able to retain the coating's biodegradability despite applied modifications to improve it's performance, the large-scale fabrication of biodegradable coatings, the coating's delamination and heat-sealability during service time, and the migration of the coating into the packaged food. Moreover, green chemistry and its sustainability needs in biodegradable polymeric coatings are also discussed regarding new ideas and possible directions for widespread application of coatings in food packaging. This is the first review that specifically summarizes biodegradable coatings on plastic and paper substrates with a focus on coating modifications to improve the performance of the base substrate to meet the required properties for food packaging applications. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Green Chemistry," published by the Royal Society of Chemistry. It features cutting-edge research on sustainable chemistry and a greener future. The contents list includes articles on topics such as electrosynthesis, sustainable chemical synthesis, corrosion science, lignin modification, and more. The journal aims to connect the world with the chemical sciences and invest profits back into the chemistry community. This document is a list of papers published in the journal Green Chemistry. The papers cover a range of topics related to sustainable and environmentally friendly chemistry. Some of the topics include the efficient fractionation of hemicellulose from hardwood pulp, the synthesis of fructose-based surfactants, and the electrochemical synthesis of formaldehyde. The papers provide valuable research for library patrons interested in these specific areas of study. [Extracted from the article]

This document is a contents list for the journal "Green Chemistry," published by the Royal Society of Chemistry. It features research papers on various topics related to sustainable chemistry, including photocatalytic upgrading of hydroxymethylfurfural, lignin extraction and nanodispersion, selenium-doped carbon materials, and the valorization of bio-renewable glycerol. The journal also includes tutorial reviews on topics such as Pickering emulsion-derived nano/microreactors and the iron ligand-to-metal charge transfer chemistry in water. Additionally, there are perspective papers, communications, and other research papers covering a range of subjects in green chemistry. The papers provide valuable insights into the development of greener and more sustainable chemical processes. [Extracted from the article]

The document is a contents list for the journal "Green Chemistry," which features articles and papers on various topics related to sustainable chemistry. The journal aims to promote research for a greener and more sustainable future. The articles cover subjects such as safe and sustainable chemicals, materials preparation, electrochemistry, natural gas and hydrogen storage, and more. The given article, titled "Boosting urea synthesis in simulated flue gas electroreduction by adjusting W– Welectronic properties," discusses a study conducted by Xiaohui Yao, Changyan Zhu, Jie Zhou, Kunhao Zhang, Chunyi Sun, Man Dong, Guogang Shan, Zhuo Wu, Min Zhang, Xinlong Wang, and Zhongmin Su. The study focuses on enhancing urea synthesis in simulated flue gas electroreduction by adjusting the electronic properties of W– W. The article provides detailed information about the research methodology and findings. [Extracted from the article]

The document is a contents list for the journal "Green Chemistry," published by The Royal Society of Chemistry. It highlights the articles and research papers included in the issue, covering topics such as waste valorization, plasticizers, noble metal recovery, bio-upcycling, CO2 reduction, and seaweed-based polysaccharides. The journal aims to promote cutting-edge research for a greener and more sustainable future. [Extracted from the article]

The document is a contents list for the journal "Green Chemistry," published by The Royal Society of Chemistry. It highlights the articles and papers featured in the current issue, covering a range of topics related to sustainable chemistry and green technologies. The articles include research on bio-based polymers, nitrogen fixation strategies, carbon aerogels for energy storage, and the use of ionic liquids in new energy and biotechnologies. The journal aims to provide cutting-edge research for a greener and more sustainable future. [Extracted from the article]

The document is a contents list for the journal "Green Chemistry," published by The Royal Society of Chemistry. It highlights the articles and research papers included in the issue, covering topics such as sustainable water treatment, lignocellulose pretreatment, and biomass valorization. The journal aims to promote cutting-edge research for a greener and more sustainable future. [Extracted from the article]

This paper describes the chemistry of green materials synthesized with supercritical fluids. First, the properties and some specific features of supercritical water are summarized. Then, supercritical hydrothermal synthesis of nanoparticles is explained, and various applications of green materials are described. The surface control of nanoparticles in supercritical water is also explained. Green processes involving chemical recycling of waste polymers and a combination of hydrothermal synthesis and supercritical water oxidation are also discussed. Finally, commercialization of supercritical water processes is discussed. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Green Chemistry," published by The Royal Society of Chemistry. It features a range of articles on topics related to sustainable chemistry, including reviews on hydrogenation of amides, manganese oxide-based catalysts, and the design of depolymerizable polymers. The journal also includes tutorial reviews on topics such as electroreductive upgradation of biomass and green synthesis of hypercrosslinked polymers. Additionally, there are perspective articles and communications on various research topics in the field of green chemistry. The papers cover a range of topics related to environmentally friendly and sustainable chemical processes, providing insights into the development of greener and more efficient chemical processes. [Extracted from the article]

Supercritical carbon dioxide (scCO2) was used to extract components of interest from Scenedesmus dimorphus, a microalgae species, under varied algal harvesting and extraction conditions. Liquid chromatography-mass spectrometry (LC-MS) was used to quantify the concentration of fatty acid methyl esters (FAME) and the FAME profile of transesterified lipids, phospholipids and pigments extracted under varied supercritical temperatures and pressures. The scCO2extraction results are compared with conventional solvent extraction to evaluate differences in the efficiency and nature of the extracted materials. Algae harvested by centrifugation (vs.lyophilization) demonstrated a similar extraction efficiency in scCO2, indicating potential energy benefits by avoiding conventional algal mass dehydration prior to extraction. Centrifuged algae and optimized extraction conditions (6000 psi; 100 °C) resulted in comparable FAME yields to conventional processes, as well as increased selectivity, reflected in the decreased pigment, nitrogen and phospholipid contamination of the FAME. Cell pre-treatments—sonication, microwave, bead beating and lyophilization—showed an enhancement in extraction yield in both conventional solvent and scCO2extraction, allowing for improved extraction efficiencies. This study suggests that scCO2, a green solvent, shows great potential for algal lipid extraction for the sustainable production of biodiesel. [ABSTRACT FROM AUTHOR]

Algae are being explored as a sustainable energy feedstock, having potential to reduce dependence on petrofuels and offset greenhouse gas emissions. Economic considerations and principles of green design suggest that if algae-to-fuel technology is to be successful, biofuels must be produced simultaneously with value-added co-products. At present, the algae industry is centered around a limited number of products, such as low-volume/high-value speciality nutrients. New products for medium- and high-volume markets will be needed as biomass production increases in scale. This Perspective highlights non-fuel applications of algal biomass that have received relatively little attention to date but are promising for future development. It is our goal to draw attention to some of the unique opportunities that algae present with respect to biochemical composition as compared to lignocellulosic energy crops. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) are widely discussed as alternative green solvents not only because of their unique chemical properties, but also because of their extremely low vapour pressure and – at least in some cases – relatively high thermal stability. Two complementary methods are analyzed and compared to determine both the rate constant of decomposition and the vapour pressure of four ILs: (1) thermogravimetrical analysis at ambient pressure (TGap) with an overflow of inert gases, and (2) high vacuum (HV) experiments with a magnetic suspension balance (MSB). At ambient pressure, [EMIM][MeSO3] and [EMIM][CF3SO3] decompose without a significant contribution of evaporation, which leads to the rate constant of thermal degradation. For both ILs, the vapour pressure can only be determined at HV by the MSB, because the evaporation rate is then higher than the decomposition rate. For the relatively volatile ILs [EMIM][NTf2] and [BMIM][NTf2] the vapour pressure can be derived both by the MSB at HV as well as by TGap. General strategies to determine the volatility and stability of ILs and criteria for the maximum operation temperature with regard to decomposition and evaporation are presented. [ABSTRACT FROM AUTHOR]

Academic research in the area of green solvents is focused on neither the industries that use solvents most nor the types of solvents that the research community believes have the best hope of reducing solvent-related environmental damage. Those of us who are primarily motivated by a desire to reduce such damage would do well to look at the major uses of solvents, to determine the problems that currently make those applications less-than-green and focus our research efforts on potential solutions to those problems. As a contribution to such efforts, I present four grand challenges in the field of green solvents: finding a sufficient range of green solvents, recognizing whether a solvent is actually green, finding an easily-removable polar aprotic solvent and eliminating distillation. [ABSTRACT FROM AUTHOR]

“The best catalyst is no catalyst.” With growing public concern over global warming and the amount of greenhouse gases, it is important to reduce the amount of chemicals and eliminate waste, to obtain better results in a simple, selective, safe, and environmentally benign fashion compared to conventional tedious chemical synthesis. Herein, we disclose an environmentally benign, rapid, catalyst/promoter/coupling reagent-free cyclization procedure of free amino acids to furnish exclusively cyclic dipeptides (2,5-diketopiperazines, DKPs) in excellent or even quantitative yield, along with their solid state self-assembling properties. This process is extremely simple and highly efficient with little or no traditional synthetic skills and without any chromatographic purification. Synthesis of structurally diverse DKPs has been achieved with a dramatic decrease in the reaction time, the amount/number of solvents used, a significant increase in the yield and nearly complete elimination of waste. As a result, this is an excellent example for the environmentally benign, clean and green chemistry concept. The most exciting outcome of our investigation is an unusual case of chiral self-recognition encountered upon the cyclization of rac-pipecolic acid, which resulted in the formation of the meso-product exclusively. [ABSTRACT FROM AUTHOR]

Both softwood (southern yellow pine) and hardwood (red oak) can be completely dissolved in the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim]OAc) after mild grinding. Complete dissolution was achieved by heating the sample in an oil bath, although wood dissolution can be accelerated by microwave pulses or ultrasound irradiation. It has been shown that [C2mim]OAc is a better solvent for wood than 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) and that variables such as type of wood, initial wood load, particle size, etc.affect dissolution and dissolution rates; for example, red oak dissolves better and faster than southern yellow pine. Carbohydrate-free lignin and cellulose-rich materials can be obtained by using the proper reconstitution solvents (e.g., acetone/water 1 : 1 v/v) and approximately 26.1% and 34.9% reductions of lignin content in the reconstituted cellulose-rich materials (from pine and oak, respectively) have been achieved in one dissolution/reconstitution cycle. The regenerated cellulose-rich materials and lignin fractions were characterized and compared with the original wood samples and biopolymer standards. For pine, 59% of the holocellulose (i.e., the sum of cellulose and hemicellulose) in the original wood can be recovered in the cellulose-rich reconstituted material; whereas 31% and 38% of the original lignin is recovered, respectively, as carbohydrate-free lignin and as carbohydrate-bonded lignin in the cellulose-rich material. [ABSTRACT FROM AUTHOR]

Silica supported platinum catalysts coated with a thin film of 1-butyl-2,3-dimethyl-imidazolium trifluoromethane sulfonate (BDiMIm) were investigated with respect to the interaction of the ionic liquid with the oxide support and the metal clusters. IR, inelastic neutron scattering and NMR spectroscopy indicate that the vibrations of the imidazolium ring of ionic liquid are less restricted when supported on SiO2, while the viscosity of the supported ionic liquid increased. The presence of Pt particles enhances the electron density of the ionic liquid at the nitrogen atom inducing higher basicity. The coverage of the catalyst surface and the metal particles by the ionic liquid protects the metal against oxidation. The catalysts are active and stable for hydrogenation of ethene. [ABSTRACT FROM AUTHOR]

The kinetic resolution (KR) and dynamic kinetic resolution (DKR) of racemic 1-phenylethanol with the acyl donor vinyl acetate catalysed by Pseudomonas cepacialipase ATCC 21808 (PCL) (this has recently been reclassified as Burholderia cepacialipase), either as the suspended native protein (PCL) or immobilised on ceramic particles (commercial lipase Amano PS CI) has been examined, as batch reactions, in supercritical carbon dioxide (scCO2). The yields and enantioselectivities achieved in these reactions were comparable to experiments conducted in hexane. The immobilised lipase PS CI displayed excellent yields (48–49%) and enantioselectivities (98–99%) to give (R)-phenylethyl acetate after 2.5 hours reaction at 40 °C in scCO2. The acylated product was obtained in higher yield in scCO2compared to the reaction carried out in hexane (yield 30–35%; ee 98–99%) under comparable conditions. Unlike PCL, the immobilised lipase PS CI could then be successfully reused with no loss of activity or selectivity observed over four reaction cycles. Combining lipase PS CI with a chemical catalyst (either the metal catalyst [Ru(p-cymene)Cl2]2or the acid catalyst Nafion SAC 13) to catalyse the racemisation of the unreacted alcohol caused an increase in the yield of the (R)-acyl phenylethanol product to 70 and 85%, respectively, in scCO2indicating a viable dynamic kinetic resolution system had been established. The enantioselectivities of the products in these reactions were slightly higher in scCO2(96% Ru-catalyst; 85% Nafion) compared to those observed in hexane (91%; 81%). The lower enantioselectivity with the acidic Nafion SAC 13 catalyses indicates that some non-enzymic acid catalysed esterification was occurring. [ABSTRACT FROM AUTHOR]

A series of task-specific ionic liquids (TSILs) based on glycerylimidazolium cations have been prepared by reaction of 1-chloropropanediol, a compound obtainable from glycerol (a widely available and in-expensive waste product), with the appropriate base (1-H-imidazole, 1,2-dimethylimidazole and 1-methyl-1-H-imidazole). The reaction of 3-(1H-imidazol-1-yl)propane-1,2-diol with chloroalkanes, bromoalkanes and alkyl mesylates gave the corresponding salts which were characterized. The possibility to use these ILs in palladium catalyzed reactions was evaluated, evidencing good catalyst stability and a high recyclability. [ABSTRACT FROM AUTHOR]

The aqueous-biphasic hydroformylation of higher alkenes catalyzed by Rh/TPPTS has been carried out in the presence of imidazolium, pyridinium and triethylammonium salts. High reaction rates are achieved with imidazolium and triethylammonium salts provided that their alkyl “tail” is ≥C8.Fast and complete phase separation, and good retention of the metal in the aqueous phase could be achieved with an octyl “tail”. Imidazolium salts were found to give the highest rate enhancement. The nature of the anion showed a moderate influence on the reaction. Evidence suggests that the additive can act as weak surfactant allowing emulsions to be formed and broken by simply switching the stirring on and off. [ABSTRACT FROM AUTHOR]

A new and environmentally friendly technology has been used successfully to produce thermoresponsive polysulfone membranes with good performance in terms of valve mechanism in the pores, with a complete on-off control of water permeability. Membranes were prepared using a CO2-assisted phase inversion method and their pores were coated/impregnated with a thermoresponsive polymer – poly(N-isopropylacrylamide) – using a new methodology for the preparation of these type of structures. The coating/impregnation efficiency was assessed by SEM and XPS analysis that confirmed the presence of nitrogen due to the thermoresponsive hydrogel. Contact angle measurements and phosphate buffer solution permeability were determined in order to characterize the structure hydrophobicity variations with temperature. The on-off mechanism was tested using a model protein (BSA) as a proof of concept for the ability to control pore apertures by temperature stimulus. A diffusion model based on Fick's law and Langmuir adsorption was developed. [ABSTRACT FROM AUTHOR]

It has been demonstrated that the pharmaceutical molecule, Ibuprofen, can be loaded into mesoporous silica using liquid (near-critical) carbon dioxide as the solvent, and that the resulting material had a high Ibuprofen content (300 mg Ibuprofen/g SiO2). A high enrichment (300 times) of Ibuprofen in the pores was observed in comparison to the Ibuprofen concentration in the solution. When similar experiments were performed in CO2(l) mixed with minor amounts (5 mol-%) of other organic cosolvents (cyclohexane, acetone or methanol), a significantly lower loading capacity of Ibuprofen into the mesoporous material was achieved. The drug-loaded mesoporous silica material was analyzed with Thermogravimetric Analysis (TGA), confocal Raman microscopy, X-ray Powder Diffraction (XRPD) and Scanning Electron Microscopy (SEM). It was found that the Ibuprofen loaded into the mesoporous silica host was amorphous and that Ibuprofen was present both at the surface and in the centre of the mesoporous silica particles. Furthermore, the SEM images did not reveal any large flakes of Ibuprofen molecules outside the mesoporous silica particles. [ABSTRACT FROM AUTHOR]

In the chemical industry organic solvents should be avoided wherever possible. They are often toxic to marine organisms and plants as well as to higher organisms and humans. Moreover, volatile organic compounds (VOC) cause air pollution which leads to the necessity of expensive separation technologies like waste water or exhaust gas treatments. Solutions for these problems are either the development of processes without the use of any solvent or the use of environmentally benign solvents such as water. In this contribution it is shown how versatile water can be, used as a solvent in homogeneously catalysed processes, for example, telomerisation reactions with methanol, diethylamine, ethylene glycol and glycerol. In this context another positive effect of the solvent water is the ecologically and economically required retention of the transition metal catalyst inside the process. Furthermore, different reactor types, a loop reactor and a mixer-settler reactor, are presented to cope with the challenges of mass transport limitations and selectivity control in aqueous biphasic systems. [ABSTRACT FROM AUTHOR]

Pressurized hot (subcritical) water and ethanol were used to extract betulin and antioxidants from birch bark. Betulin was found to be the major compound (around 26% (w/w)), which was able to be extracted with ethanol (120 °C, 50 bar, 15 minutes) but not with water at any of the temperatures tested (40–180 °C, 50 bar). The obtained extraction result for betulin is supported by theoretical solvation parameter calculations. Furthermore, high antioxidant activity of the extract was obtained using both ethanol and water as solvent. The antioxidant activity, as determined by a DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, was found to be highest for the water extract of finely ground bark and it markedly increased with elevated extraction temperatures (90–180 °C). To elucidate if this was due to increased extraction efficiency or chemical reactions, a set of experiments was performed in which the samples were pre-treated with water at different temperatures before extraction. Results from liquid chromatography showed some differences in molecular composition between samples pre-treated at ambient and 180 °C, respectively. However, more detailed studies have to be performed to distinguish between hot-water extraction and reaction kinetics. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Green Chemistry," published by the Royal Society of Chemistry. It highlights the articles and papers included in the current issue, covering a range of topics related to sustainable chemistry and green research. The articles discuss subjects such as catalytic depolymerization of plastics, lignin applications, and the design of bifunctional catalysts. The journal also offers information on training courses and events for professional development in the field of chemistry. [Extracted from the article]

The document is a contents list for the journal "Green Chemistry," which focuses on cutting-edge research aimed at reducing the environmental impact of the chemical industry. It covers a range of topics, including the role of fungal enzymes in pharmaceutical synthesis, carbon-based electrocatalysts for hydrogen production, and the recycling of fiber-reinforced polymer composites. The journal is published by the Royal Society of Chemistry and is available electronically. The document is a compilation of various research papers published in the journal, covering topics related to sustainable chemistry and green technologies, such as the synthesis of renewable building blocks, the destruction of organic pollutants, electrochemical reactions, and the recycling of waste materials. Each paper presents its own findings and research methods. [Extracted from the article]

A recent article in Green Chemistry highlights the development of a biodegradable and sustainable paper coating material. Traditional coating materials used in paper packaging contribute to plastic pollution, so researchers from KAIST and Yonsei University in South Korea have developed a boric acid-crosslinked polyvinyl alcohol coating that improves barrier properties and mechanical robustness without compromising biodegradability and biocompatibility. This advancement offers a greener solution for sustainable packaging. The article also includes information about the optimization of 5-hydroxymethylfurfural oxidation through a photo-enzymatic cascade process. [Extracted from the article]

Developing green analytical approaches has become a crucial trend in green chemistry. These approaches encourage direct analysis to avoid any sample treatment that involves energy and reagent consumption or the generation of waste. In this study, a green sensitive analytical workflow was developed for the direct analysis of anionic compounds via a charge inversion strategy using matrix-assisted ionization and a miniature mass spectrometer. Per- and polyfluoroalkyl substances (PFAS), which are a representative category of emerging pollutants, were selected as model analytes for method development. An imidazolium-based germinal dicationic ionic liquid (DIL), 1,1-bis(3-methylimidazolium-1-yl) butylene difluoride ([C4(MIM)2]F2), was chosen as a charge donor to form positively charged complexes with the PFAS for mass spectrometry (MS) analysis. Without any sample treatment, 1 μL of sample was loaded on a paper strip, followed by the addition of a mixture of 3-nitrobenzonitrile and [C4(MIM)2]F2. The adduct complexes were analyzed using a miniature mass spectrometer with tandem MS capability. The signal intensity was enhanced by up to two orders of magnitude in positive ion mode compared to negative ion mode without a DIL. The developed protocol was validated and satisfactory sensitivity was obtained, with limits of detection and quantitation ranging from 5 to 10 μg L−1. Recoveries ranging from 86.6% to 106.3% were achieved, with relative standard deviations between 3.5% and 9.3%. As indicated by three typical green analytical chemistry metric tools, this analytical procedure had a high degree of greenness. The developed protocol was applied to the analysis of real environmental and municipal water samples, demonstrating good potential for the rapid on-site analysis of anionic compounds. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Green Chemistry," which focuses on reducing the environmental impact of the chemical industry through non-toxic technologies. The journal includes tutorial reviews on topics like biomass energy and sustainable haircare, as well as critical reviews and communications on various research topics. Published by The Royal Society of Chemistry, the journal offers a compilation of research papers covering sustainable and environmentally friendly chemistry. Topics range from organic compound synthesis to photocatalytic reactions, plastic waste upcycling, and catalyst development. These papers provide valuable insights and advancements in the field of green chemistry. [Extracted from the article]

Microwave heating was found to have a beneficial effect on the enzymatic esterification of lactic acid (LA) with ethanol in Cyphos 202 ionic liquid (IL) medium. Microwave irradiation caused hydrolysis of lactoyllactic acid (the linear dimer of LA) during the reaction, thus, as a result, more lactic acid was available as substrate and a higher ester yield was achieved in the esterification. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Green Chemistry," published by the Royal Society of Chemistry. It features articles on various topics related to sustainable chemistry, including catalytic production of 1,4-pentanediol from biomass, the application of ionic liquid systems in recycling lithium-ion batteries, and the synthesis of lactic acid and carbon dots using food waste and seashell waste. The journal aims to provide cutting-edge research for a greener and more sustainable future. [Extracted from the article]

The document is a contents list for the journal "Green Chemistry," published by The Royal Society of Chemistry. It highlights various articles and papers featured in the journal's latest issue, covering topics such as sustainable chemistry, electrocatalysis, and environmentally friendly synthesis methods. The journal aims to promote research for a greener and more sustainable future. [Extracted from the article]

Chemicals are a part of modern life. Products are the main emissions of the chemical and pharmaceutical industries. This makes it difficult to hold them back efficiently. Very often they do not become degraded or fully broken down to water, carbon dioxide and inorganic salts. Often, unknown transformation products are formed in the environment. Therefore, according to the principles of green chemistry, the functionality of a chemical should not only include the properties of a chemical necessary for its application, but also easy and fast degradability after its use. Taking into account the full life cycle of chemicals will lead to a different understanding of the functionality necessary for a chemical. In the present discussion, improvement of synthesis and renewable feedstock are very prominent, whereas the environmental properties of the molecules are somewhat underestimated. To stimulate the discussion about the future role of degradable chemicals several examples are presented to underline the feasibility and the economic potential of this approach, called benign by design. [ABSTRACT FROM AUTHOR]

Recently, poly(ionic liquid)s (PILs) have emerged as a family of polymeric materials which are being increasingly investigated for interdisciplinary applications. Their high electrical conductivity, excellent thermal/mechanical stability, low vapor pressure, and easy processibility render PILs exceptionally attractive as versatile platforms for green chemistry. Recent decades have witnessed fruitful efforts devoted to the development of PIL-based green chemistry platforms, achieving significant discoveries that will unfold their uniqueness in catalysis, separation, sensors, electrolyte, and functional materials. However, few review papers offer comprehensive discussion on PILs' application in the green chemistry field. In this review, we initially introduce the structure and types of PILs, which is followed by a systematical summary of the synthesis of PILs in terms of direct polymerization of monomer, polymerization after monomer modification, and modification of polymers. Furthermore, several aspects of the application of PILs related to green chemistry are highlighted, such as sensors, separation, catalysis, electrolytes for energy storage devices, and as versatile precursors yielding functional materials. Current challenges and corresponding research directions in PILs for green chemistry are clarified, to make PILs truly green platforms for existing technologies. [ABSTRACT FROM AUTHOR]

The existing methods for obtaining titanium are harmful as toxic organic solvents must be used. In this paper, three magnetic ionic liquids (MILs) and five hydrophobic deep eutectic solvents (HDESs) were designed and combined for safer extraction of titanium from an HCl leachate of ilmenite (HLI). First, the physicochemical properties including density, viscosity, water content, total organic carbon, and appearance and extraction performance including efficiency, selectivity and reusability of the designed solvents were thoroughly analyzed and compared. Second, the most suitable cation to form MILs for the removal of iron and the best HDES for the extraction of titanium were defined based on sustainable chemistry metrics. The purity of the obtained titanium solution could reach 99.87% after the combined use of the selected MIL and HDES. Finally, toxicity studies on the reagents applied were performed and compared with existing methods. [ABSTRACT FROM AUTHOR]

In this paper, a set of copper-based ternary deep eutectic solvents (Cu-DESs) is synthesized and applied in Glaser-type homo- and cross-coupling of terminal alkynes. These reactions occur under exogenous-ligand-free, base-free, and additive-free conditions and provide satisfactory to excellent yields (up to 99%) under mild conditions. The Cu-DESs can be recycled eight times and the only by-product is water, which fully accords with the principles of green chemistry. [ABSTRACT FROM AUTHOR]

GreenChemistry Cutting- edge research for a greener sustainable future rsc. li/ greenchem ISSN 1463- 9262 Volume 26 Number 16 21 August 2024 Pages 8883- 9272 PAPER Xiujuan Li et al. Harnessing solvation- guided engineering to enhance deep eutectic solvent resistance and thermostability in enzymes [Extracted from the article]

GreenChemistry Cutting- edge research for a greener sustainable future rsc. li/ greenchem Volume 26 Number 16 21 August 2024 Pages 8883- 9272 ISSN 1463- 9262 PAPER Sara Iborra, Avelino Corma et al. Chemoenzymatic synthesis of amino- esters as precursors of ammonium salt- based surfactants from 5- hydroxymethylfurfural ( HMF) [Extracted from the article]

GreenChemistry Cutting- edge research for a greener sustainable future rsc. li/ greenchem Volume 26 Number 15 7 August 2024 Pages 8433- 8882 ISSN 1463- 9262 PAPER George W. Huber et al. Aliphatic amines from waste polyolefi ns by tandem pyrolysis, hydroformylation, and reductive amination [Extracted from the article]

GreenChemistry Cutting- edge research for a greener sustainable future rsc. li/ greenchem ISSN 1463- 9262 Volume 26 Number 15 7 August 2024 Pages 8433- 8882 PAPER André Bardow et al. Early- stage impact assessment tool ( ESTIMATe) for the life cycle assessment of CO 2 - based chemicals [Extracted from the article]

Effective use of quantitative metrics is fundamental to guiding innovation toward more sustainable chemicals. At present, metrics employed in Green Chemistry, such as the E-factor, Process Mass Intensity, or Energy Intensity, focus on mass or energy efficiency at specific levels -- reaction, process, or plant. However, a more holistic approach is needed, especially at early stages of research and development, utilising more complex impact-based indicators from Life Cycle Assessments (LCAs) to gain a deeper understanding of the environmental footprint of chemical systems. To date, the need to couple mass- and energy-based process metrics with life cycle impacts for more comprehensive assessments has been qualitatively discussed but not quantitatively demonstrated. Therefore, this study quantifies the level of correlation and linkages between five mass- and energy-based metrics and 16 LCA indicator scores by leveraging data for over 700 chemical manufacturing processes. The primary finding is the weak correlations between process metrics and life cycle impacts, as the former approach lacks appropriate weights for each input and output to account for their life cycle environmental implications. While improving process efficiency can lead to lower overall environmental impact, enhanced granularity for comparing alternative chemical routes provides insights into the relative impact levels throughout the supply chain, particularly concerning raw materials as they are major contributors to life cycle environmental impacts. This study also provides practical insights for expanding the application of LCA by making it more accessible to the research community through simplified approaches and working collaboratively with LCA practitioners. [ABSTRACT FROM AUTHOR]

High-quality liquid biofuels can be produced from renewable lignin-derived phenolic compounds through an efficient hydrodeoxygenation (HDO) process in which the traditional catalysts usually include metal sites and acid sites that catalyze the hydrogenation and deoxygenation procedures respectively. This work presents a novel acid-free NixMoyN/C catalyst from the perspective of green chemistry providing a new pathway for HDO of lignin-derived phenolic compounds that involves hydrogenation deoxygenation and hydrogenolysis at the same time. A series of NixMoyN/C catalysts were prepared by varying the Ni :Mo molar ratio among which the Ni1Mo3N/C catalyst showed the best HDO performance. Guaiacol could be completely converted at 260 °C after 4 h with 95.8% cyclohexane selectivity. In addition a small amount of benzene could be obtained as a valuable fuel additive by-product by altering the conventional HDO reaction path. By shortening the reaction time benzene could be obtained as an intermediate product with a relative high selectivity. Based on the characterizations using XRD BET SEM TEM XPS H2-TPD and EPR, the results demonstrate that the multiple active components of the Ni1Mo3N/C catalyst allow it to efficiently catalyze the hydrogen activation and C--O bond cleavage even under acid-free conditions. The existence of the active phases of Ni Ni2Mo3N and β-Mo2C as well as the interaction between Ni and Mo metals together contributed toward efficient HDO performance. Not only for the various phenolic model compounds the feasibility of Ni1Mo3N/C catalysts for upgrading raw lignin oil was also demonstrated with the hydrocarbon content increasing from 5.7% to 88.4%. Notably arenes accounted for 18.2% of the hydrocarbon products which confirmed the occurrence of hydrogenolysis in the catalytic process. This work provides a novel route for the conversion of lignin-derived phenolic compounds to produce high-quality hydrocarbon liquid biofuels especially the direct production of arene components. [ABSTRACT FROM AUTHOR]

Strategies facilitating the synthesis of heterocycles using green methodologies have modernized their syntheses in synthetic and pharmaceutical chemistry. In the present study, a highly well-organized, ecofriendly and straightforward synthetic approach was developed for the microwave-assisted synthesis of fused pyrazolopyridines and spirooxindole-fused pyrazolopyridines using an economical metal--organic framework, HKUST-1, in ethanol. The prepared MOF was characterized through diverse techniques, including FT-IR, p-XRD, SEM, TEM, EDX, TGA and BET. This approach shows noteworthy advantages, such as good yields, simple and clean reaction conditions, shorter reaction time, use of a highly efficient and sustainable catalyst and no chromatographic separation as the entire products can be purified through recrystallization. Moreover, green chemistry metrics for compounds 4a, 6a, 8a and 9a were calculated and were found to be very close to ideal values. The TON and TOF of the catalyst reached 32.75 and 3.27 min-1, respectively, for this transformation. In vitro anti-bacterial screening of these synthesized derivatives was performed against the Gram-negative bacteria Escherichia coli (E. coli) and Gram-positive bacteria Staphylococcus aureus (S. aureus). Compounds 4a and 6f showed activity against all the bacteria tested in the experiment. Further, the anti-tubercular study of the synthesized compounds revealed that compound 4b had the highest activity among all the synthesized derivatives. [ABSTRACT FROM AUTHOR]

Due to the high oxidation potential of arenes and alkenes, previous methods of benzylic and allylic C–H oxidation necessitated the use of strong oxidizing agents, metal catalysts, or free radical initiators (such as photocatalysts or hydrogen atom transfer reagents) to be effective. Herein, we employ oxygen to generate a triple-spin charge transfer state with π-conjugated compounds effectively accessing the triplet excited states of arenes, followed by energy transfer to form singlet oxygen facilitating C–H bond oxidation. Distinct from previous oxidations, it is the first time that a series of natural products and drug molecules (27 examples) are selectively oxidized without any catalysts or additives. The transformation can be implemented under sunlight to produce valuable unsaturated (aromatic) ketones and only water as waste, which meets every one of the 12 principles of green chemistry. [ABSTRACT FROM AUTHOR]

The properties of natural products can be significantly influenced by glycosylation, emphasizing the key role of glycosyltransferases (GTs) in this process. The pursuit of tailored GT catalysts to meet the demands of the glycosylation industry aligns with the principles of green chemistry. However, steering GT engineering towards the desired direction often requires substantial effort. Herein, we employ a comparative molecular dynamics approach to guide the engineering of GTs to alter their catalytic performances. Through comparing the structural flexibility and site-saturation mutagenesis of two GTs BarGT-1 with narrow substrate scope and BarGT-3 with wide substrate scope, the identified substitution K321P in C-loop 5 of BarGT-1 greatly expanded the substrate scope towards diverse pharmaceutically valuable substrates, thereby the catalytic efficiencies were remarkably improved (e.g., 52- and 244-fold for 4′- and 6-hydroxyflavone, kcat/KM). Further, phylogenetic analysis demonstrated that lysine was a highly conserved residue in the GTs within BarGT-1 branch, and its key roles in regulating the substrate scope were validated through site-saturation mutagenesis in two novel GTs, BsyGT (K321F) and BgoGT (K322W). Moreover, the corresponding substitutions G325R/D in C-loop 5 of BarGT-3 also served as switches to regulate the substrate profile of BarGT-3. Finally, through the utilization of BarGT-1 and K321P, we successfully regulated the synthesis of valuable liquiritigenin glycosides with minor effort. The comparative molecular dynamics approach provides insights into the structural dynamics of GTs, optimizes enzymatic processes, and facilitates precise enzyme engineering, offering a directed synthetic paradigm to produce valuable glycosides. [ABSTRACT FROM AUTHOR]

Single-atomic metal catalysts are attractive for green chemistry in terms of their outstanding catalytic performance and savings in precious metal usage owing to maximized metal utilization, including anode catalysts in polymer electrolyte fuel cells (PEFCs). Heteroatom-doped porous carbons are extensively used as supports, where the heteroatoms contribute to the immobilization of single-atomic metals. However, high-content doping of heteroatoms, especially sulphur (S), into carbon supports is still challenging because S species can be readily desorbed during heat treatment. Herein, we present a bottom-up fabrication approach for S-rich porous carbons from molecular precursors via a thermal polymerization process. A simple carbonization of molecules with thermally stable S-containing building blocks and polymerizable ethynyl moieties at 900 °C yields microporous carbon materials with record-high S content (over 15 wt%). The abundant S species function as an effective anchoring site for single-atomic platinum (Pt) species. Toward anode catalysts in PEFCs, the prepared single-atomic Pt catalysts efficiently promote the electrochemical hydrogen oxidation reaction, whose activity is comparable to that of commercial Pt/C, despite the significantly low Pt loading amount. [ABSTRACT FROM AUTHOR]

GreenChemistry Cutting- edge research for a greener sustainable future rsc. li/ greenchem ISSN 1463- 9262 Volume 26 Number 14 21 July 2024 Pages 8041- 8432 PAPER Chia- Yu Lin et al. Effi cient and selective electrosynthesis of adiponitrile by electrohydrodimerization of acrylonitrile over a bismuth nanosheet modifi ed electrode [Extracted from the article]

GreenChemistry Cutting- edge research for a greener sustainable future rsc. li/ greenchem Volume 26 Number 14 21 July 2024 Pages 8041- 8432 ISSN 1463- 9262 PAPER Robert Wojcieszak, Ivaldo Itabaiana et al. Optimization of 5- hydroxymethylfurfural oxidation via photo- enzymatic cascade process [Extracted from the article]

GreenChemistry Cutting- edge research for a greener sustainable future rsc. li/ greenchem ISSN 1463- 9262 Volume 26 Number 13 7 July 2024 Pages 7429- 8040 PAPER Luigi Vaccaro et al. A waste- minimized approach for the synthesis of iodinated organic borazines [Extracted from the article]