Biopolymers for surface engineering of paper-based products

The combination of biopolymer science and technology with surface engineering of paper-based cellulosic materials has a lot of potential in stepping forward to a sustainable future. Various biopolymers such as oxidized starch, carboxymethyl cellulose, and polylatic acid have been commercially used to engineer paper surface. The paper-based cellulosic products are widely used for printing/writing and packaging applications. However, the production of these products are currently dependent mainly upon the use of petroleum-based materials including synthetic pigment coating latexes and barrier coating materials. The major challenges associated with some biopolymers are their relatively high costs and unsatisfactory performances. Continuing efforts are being made to enable the increased and value-added use of various biopolymers in paper surface engineering. These polymers can be based on cellulose, hemicelluloses, chitosan, alginate, protein, polylactic acid, and polyhydroxyalkanoate. The biopolymer-engineered paper products can be tailored for use as substitutes for various non-renewable materials including plastics and metals as well. Future development in the area of biopolymers for paper surface engineering is likely to lead to new possibilities and breakthroughs, paving the way for a substantially sustainable and green future.     

Application of direct (hetero)arylation in constructing conjugated small molecules and polymers for organic optoelectronic devices

Direct (hetero)arylation, as a sustainable, atom-economic and environmentally benign synthetic protocol compared to conventional coupling techniques, has been extensively applied to the sustainable preparation of π-conjugated materials for organic optoelectronic devices. In this review, we will highlight recent advances made in direct arylation for conjugated small molecules and polymers toward high performance organic optoelectronic devices. Some important insights in direct arylation for synthesizing organic optoelectronic materials are given, together with the challenges and outlook in this significant and hot research field.     

Preparation and Characterization of Electroactive Biopolymers

Biopolymers have the potential for use as a matrix for applications such as controlled release devices, environmentally sensitive membranes, mimic materials and energetic applications. Renewable resources (such as starch) can be utilized as polymer matrices for electroactive materials that are sensitive to their environment. Natural polymers are generally more environmentally-friendly and biocompatible than existing synthetic products. Thermoplastic starch is naturally insulative; however, the chemical, electrical, and mechanical properties of the biopolymer matrix can be tailored for specific functionality in a continuous process utilizing reactive extrusion. Conductance can be measured in the solid state by a direct-current resistance method. Ion-conducting materials, produced by doping thermoplastic starch and biopolymers with metal halides, have 5 orders of magnitude greater conductance than native materials. There is a correlation between polymer mobility and conductance. Plant or microbial biopolymers with ionic functional groups have shown promise for higher levels of conductance. The conductance approaches the level of synthetic polymer electrolytes.     

Green Synthetic Approach: An Efficient Eco-Friendly Tool for Synthesis of Biologically Active Oxadiazole Derivatives

Green synthetic protocol refers to the development of processes for the sustainable production of chemicals and materials. For the synthesis of various biologically active compounds, energy-efficient and environmentally benign processes are applied, such as microwave irradiation technology, ultrasound-mediated synthesis, photo-catalysis (ultraviolet, visible and infrared irradiation), molecular sieving, grinding and milling techniques, etc. Thesemethods are considered sustainable technology and become valuable green protocol to synthesize new drug molecules as theyprovidenumerous benefits over conventional synthetic methods.Based on this concept, oxadiazole derivatives are synthesized under microwave irradiation technique to reduce the formation of byproduct so that the product yield can be increased quantitatively in less reaction time. Hence, the synthesis of drug molecules under microwave irradiation follows a green chemistry approach that employs a set of principles to minimize or remove the utilization and production of hazardous toxic materials during the design, manufacture and application of chemical substances.This approach plays a major role in controlling environmental pollution by utilizing safer solvents, catalysts, suitable reaction conditions and thereby increases the atom economy and energy efficiency. Oxadiazole is a five-membered heterocyclic compound that possesses one oxygen and two nitrogen atoms in the ring system.Oxadiazole moiety is drawing considerable interest for the development of new drug candidates with potential therapeutic activities including antibacterial, antifungal, antiviral, anticonvulsant, anticancer, antimalarial, antitubercular, anti-asthmatic, antidepressant, antidiabetic, antioxidant, antiparkinsonian, analgesic and antiinflammatory, etc. This review focuses on different synthetic approaches of oxadiazole derivatives under microwave heating method and study of their various biological activities.     

Recent progress and current applications of Sonogashira coupling reaction in water

The use of aqueous media in palladium‐catalyzed reactions has become popular because water‐based synthetic processes are inherently safer as well as being inexpensive. Moreover, it does not require dry solvents, and the products may easily be isolated by extraction, which greatly facilitates the operation. Thus the use of water in palladium‐catalyzed reactions represents one of the most economically and environmentally viable options for many organic transformations. In this review, recent developments of Sonogashira reaction in water or aqueous media will be disclosed. Copyright © 2013 John Wiley & Sons, Ltd.     

Environmentally Friendly Techniques and Their Comparison in the Extraction of Natural Antioxidants from Green Tea,Rosemary, Clove,and Oregano

Many current food and health trends demand the use of more ecological, sustainable, and environmentally friendly techniques for the extraction of bioactive compounds, including antioxidants. However, extraction yields and final antioxidant activities vary between sources and are highly influenced by the given extraction method and nature and ratio of the employed solvent, especially for total polyphenols, flavonoids, and anthocyanins, which are well recognized as natural antioxidants with food applications. This review focused on the most common extraction techniques and potential antioxidant activity in the food industry for various natural antioxidant sources, such as green tea, rosemary, clove, and oregano. Green extraction techniques have been proven to be far more efficient, environmentally friendly, and economical. In general, these techniques include the use of microwaves, ultrasound, high hydrostatic pressure, pulsed electric fields, enzymes, and deep eutectic solvents, among others. These extraction methods are described here, including their advantages, disadvantages, and applications.     

Controlled synthesis of CdSe quantum dots by a microwave-enhanced process: a green approach for mass production

A method that does not employ hot-injection techniques has been developed for the size-tunable synthesis of high-quality CdSe quantum dots (QDs) with zinc blende structure. In this environmentally benign synthetic route, which uses less toxic precursors, solvents, and capping ligands, CdSe QDs that absorb visible light are obtained. The size of the as-prepared CdSe QDs and thus their optical properties can be manipulated by changing the microwave reaction conditions. The QDs were characterized by XRD, TEM, UV/Vis, FTIR, time-resolved fluorescence spectroscopy, and fluorescence spectrophotometry. In this approach, the reaction is conducted in open air and at a much lower temperature than in hot-injection techniques. The use of microwaves in this process allows for a highly reproducible and effective synthesis protocol that is fully adaptable for mass production and can be easily employed to synthesize a variety of semiconductor QDs with the desired properties. Possible applications of the CdSe QDs were assessed by deposition on TiO(2) films.     

Boosting Visible-Light Carbon Dioxide Reduction with Imidazolium-Based Ionic Liquids

Efficiently generating C₁ building blocks from environmentally friendly carbon sources, such as through photocatalytic CO₂ reduction, is essential for fostering a sustainable circular economy. The pursuit of mild catalytic activation methods has yielded powerful catalysts that can be synergistically employed alongside various reaction media to enhance overall performance. Herein, we elucidate the influence of diverse imidazolium-based ionic liquids as additives for visible-light-driven CO₂ reduction with ruthenium(II)- and rhenium(I)-bipyridine complexes. Our investigation reveals that incorporating ionic liquids into traditional solvents at concentrations below 10 % can markedly boost CO production while suppressing H₂ generation. The best results were obtained for the highly basic ionic liquid [C₂mim][OAc], resulting in a substantial rise in CO formation from 0.3 μmol/h to 5.4 μmol/h and an increase in turnover number from 3 to 59. This study underscores the cooperative influence of imidazolium-based ionic liquids on CO₂ photoreduction while circumventing their use as primary solvents, thus offering a promising avenue for sustainable chemical synthesis.     

Diatomaceous Earth for Arthropod Pest Control: Back to the Future

Nowadays, we are tackling various issues related to the overuse of synthetic insecticides. Growing concerns about biodiversity, animal and human welfare, and food security are pushing agriculture toward a more sustainable approach, and research is moving in this direction, looking for environmentally friendly alternatives to be adopted in Integrated Pest Management (IPM) protocols. In this regard, inert dusts, especially diatomaceous earths (DEs), hold a significant promise to prevent and control a wide range of arthropod pests. DEs are a type of naturally occurring soft siliceous sedimentary rock, consisting of the fossilized exoskeleton of unicellular algae, which are called diatoms. Mainly adopted for the control of stored product pests, DEs have found also their use against some household insects living in a dry environment, such as bed bugs, or insects of agricultural interest. In this article, we reported a comprehensive review of the use of DEs against different arthropod pest taxa, such as Acarina, Blattodea, Coleoptera, Diptera, Hemiptera, Hymenoptera, Ixodida, Lepidoptera, when applied either alone or in combination with other techniques. The mechanisms of action of DEs, their real-world applications, and challenges related to their adoption in IPM programs are critically reported.     

A preliminary spectroscopic investigation on the molecular interaction of metal-diphenylthiocarbazone complex with cellulose biopolymer and its application

Biopolymer adsorbents are versatile in their application for removal of heavy metals. The present work is focused towards the preliminary study of the interaction of diphenylthiocarbazone (DTZ) complex of chromium(VI) in acidic medium with cellulose biopolymer. Chromium-DTZ complex could be quantitatively adsorbed on a cellulose column in the pH range 1.0-2.5 and the effect of various experimental parameters such as stability of the column and the complex, column breakthrough volume, and interfering ions have been studied in detail. The probable mechanism of adsorption of complex on the cellulose biopolymer was corroborated using Fourier transform infra-red spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and solid state 13C nuclear magnetic resonance techniques (CP-MAS). The pores formed due to the hydrogen bond between the cellulose layers and then the ensuing occupation of the complex between these layers and on the surface of the biopolymer layer through electrostatic attractive force and Π interaction of aromatic ring with cellulose are expected to play a vital role in the interaction. The cellulose column could be regenerated using environmentally benign polyethylene glycol-400 (PEG-400) in acidic medium. The cellulose biosorbent has been successfully tested to study the removal of chromium as its dithizone complex from synthetic and real waste water samples.     

Dy(OTf)3 Catalyzed Reaction of Indole with Aldehydes and Ketones in Ionic Liquids

The use of environmentally benign reaction media is very important in view of today' s environmentally con scious attitude. In connect with this, room temperature ionic liquids that are air and moisture stable have received a good deal of attention in recent years as novel solvent systems for organic synthesis. A number of reactions such as Friedel-Crafts reactions, Diels-Alder cycloadditions, hydrogenations, and Heck reactions have employed ionic liquids as solvents. Among them, the Friedel-Crafts reaction[1] is of great synthetic significance in view of laboratory synthesis and industrial production. Recent studies showed that Friedel-Crafts reaction of indole with carbonyl compounds proceeded readily in aqueous media. [2] However, the aqueous reactions suffer from some common problems,such as tedious work-up, reuse of catalyst and so on.     

在还原剂存在下CO2作为碳源合成苯并噻唑反应的研究进展

CO₂是一种来源丰富、价廉易得的C1资源。将CO₂高值化利用是“双碳”目标实现的途径之一。苯并噻唑类化合物广泛应用于医药、农药等领域。因此,从绿色和可持续发展角度来看,利用CO₂作为碳源合成杂环化合物苯并噻唑具有重要的意义。本文综述了氢气、硅烷和硼烷三类还原剂还原CO₂与邻氨基苯硫酚反应合成苯并噻唑的方法,分析了各种方法的优缺点,阐述了采用不同还原剂的反应机理,并指出了这一领域面临的问题。另外,对该领域未来的发展方向进行了展望,如绿色环保溶剂的使用、新型高效还原剂的研究、苯并噻唑新合成路线的设计等。     

New Copper,Palladium and Nickel Catalytic Systems: An Evolution towards More Efficient Procedures

Metal‐catalysed reactions are a fundamental tool in synthetic chemistry. Increasingly challenging transformations can be accomplished only by means of certain metal catalysts. However, there still remains the need for a substantial decrease of the amount of catalyst, for better reuse or recycling of such active species, and for the avoidance of relatively toxic solvents in favour of environmentally friendly media. These facts apply to copper‐, palladium‐, and nickel‐catalysed cross‐coupling reactions, direct arylations, and oxidative processes. This account summarises our research on the last reactions, featuring an evolution towards more sustainable procedures in this field.     

Agarose‐ and alginate‐based biopolymers for sample preparation: Excellent green extraction tools for this century

Recently, there has been considerable interest in the use of miniaturized sample preparation techniques before the chromatographic monitoring of the analytes in unknown complex compositions. The use of biopolymer‐based sorbents in solid‐phase microextraction techniques has achieved a good reputation. A great variety of polysaccharides can be extracted from marine plants or microorganisms. Seaweeds are the major sources of polysaccharides such as alginate, agar, agarose, as well as carrageenans. Agarose and alginate (green biopolymers) have been manipulated for different microextraction approaches. The present review is focused on the classification of biopolymer and their applications in multidisciplinary research. Besides, efforts have been made to discuss the state‐of‐the‐art of the new microextraction techniques that utilize commercial biopolymer interfaces such as agarose in liquid‐phase microextraction and solid‐phase microextraction.     

Optimization of a Sustainable Protocol for the Extraction of Anthocyanins as Textile Dyes from Plant Materials

Anthocyanins are the largest group of polyphenolic pigments in the plant kingdom. These non-toxic, water-soluble compounds are responsible for the pink, red, purple, violet, and blue colors of fruits, vegetables, and flowers. Anthocyanins are widely used in the production of food, cosmetic and textile products, in the latter case to replace synthetic dyes with natural and sustainable alternatives. Here, we describe an environmentally benign method for the extraction of anthocyanins from red chicory and their characterization by HPLC-DAD and UPLC-MS. The protocol does not require hazardous solvents or chemicals and relies on a simple and scalable procedure that can be applied to red chicory waste streams for anthocyanin extraction. The extracted anthocyanins were characterized for stability over time and for their textile dyeing properties, achieving good values for washing fastness and, as expected, a pink-to-green color change that is reversible and can therefore be exploited in the fashion industry.     

Analytical developments and applications of ionic liquids for environmental studies

Ionic liquids (ILs) are considered advanced solvents with interesting properties that have led to remarkable improvements in the performance of analytical methods and their practical application. Analytical chemistry has profited from the evolution of ILs in diverse contexts, ranging from their applications in microextractions to uses as matrices for mass spectrometric determinations. Their use in sample preparation has meant significant improvements in terms of miniaturization and analytical performance, and given place to new techniques based on liquid-liquid and solid-phase extractions; the latter greatly driven forward by the combination of ILs with nanomaterials. Furthermore, electrodes have been prepared by combining ILs with different modern materials, significantly improving the sensitivity and selectivity of electroanalytical methods. Moreover, the implementation of ILs as additives to mobile and stationary phases in separation techniques has been proved to improve liquid and gas chromatography, as well as capillary electrophoresis, in terms of the number of analytes that can be efficiently separated and of the useful life of columns, representing also a promising alternative to environmentally dangerous organic solvents. Additionally, their application as matrix modifiers and as ion-pairing additives has introduced their use in mass spectrometry. In this review, the design and implementation of innovative and highly efficient analytical methods based on ILs for the sensitive and selective determination of diverse analytes in environmental matrices is described. Critical issues that have arisen from their application and future challenges in electrochemical, separation and preconcentration techniques based on these solvents are also presented.     

Mechanochemical Suzuki-Miyaura Cross-Coupling with Natural Deep Eutectic Solvent as Liquid-Assisted Grinding Additive: Merging Two Fields for a Greener Strategy

The use of volatile solvents for organic synthesis is nowadays questioned due to their negative impact on the environnement. To develop sustainable and environmentally friendly methodologies, we propose to combine two green chemistry concepts: the use of bioinspired solvents: natural deep eutectic solvents (NaDES), and mechanochemistry. Using the Suzuki-Miyaura coupling as a model reaction, we described an efficient mechanochemical method with NaDES as a LAG (liquid-assisted grinding) additive with short reaction times and without any ligand or additional heating. A mechanochemical extraction was also used to reduce the amounts of extraction solvents and the total time of the synthesis process.     

Chromatographic assessment of biodiesel production from Peganum harmala seed oil using environmentally benign nano-catalysts

This work gives a comprehensive chromatographic assessment of biodiesel generation from plant seed oil using ecologically friendly nano-catalysts. Researchers all over the world are actively looking for new ways to satisfy the urgent need for clean and renewable energy sources. The resultant biodiesel was fully characterized utilizing modern techniques like scanning electron microscopy, energy diffraction X-ray and X-ray diffraction. The biodiesel gas chromatography/mass spectrometry analysis revealed four significant peaks of fatty acid methyl esters, indicating high-quality biodiesel production. Furthermore, the biodiesel fuel qualities were discovered to be comparable with international standards such as ASTM D-6571 and EN-14214. This indicates that the iron-modified clay nano-catalyst can be used as a catalyst for large-scale biodiesel production. This work is important because it could lead to the large-scale production of a novel, non-food feedstock. We may lessen our reliance on fossil fuels and contribute to a more sustainable and ecologically friendly energy future by leveraging the usage of biodiesel produced in this way. The chromatographic assessment of biodiesel production from non-edible seed oil using environmentally benign nano-catalysts holds significant promise in advancing sustainable and eco-friendly biodiesel production methods, contributing to a cleaner and more environmentally responsible energy sector.     

Low-Temperature Fast Production of Carbon and Acetic Acid Dual-Promoted Pd/C Catalysts

The Pd/C catalysts are widely used in synthesis of fine chemicals in industry, but their production suffers from a complicated two-step process involving impregnation and reduction, and requires large amounts of solvents and reductant, which would lead to a series of issues such as time consumption, resource waste and environmental pollution. Herein, ultra-small Pd nanoparticles uniformly anchored on carbon nanotubes (Pd/CNTs) were synthesized by using a one-pot and low-temperature reduction strategy. The present process/technology is very sensitive to and controlled by the supports and solvents, and the carbon support and acetic acid synergistically play crucial and decisive roles in the fast production of Pd/C catalysts. Also, the used solvents can be recycled and reutilized, which meets the requirements of sustainable chemistry and green economy. When the as-obtained Pd/CNTs catalyst was used to catalyze the oxidation of benzyl alcohol to benzaldehyde, it achieved a conversion efficiency as high as 99.3 % and a high selectivity up to >99.9 %. The simple, scalable and environmentally friendly strategy can be extended to anchor Pd nanoparticles on various carbon substrates, which sheds a new light on the synthesis of Pd/C catalysts.