Aspects Of Green Chemistry Research Articles

A new grey relational analysis application in analytical chemistry: Natural deep eutectic solvent as a green extractant for HPLC determination of lamotrigine in plasma

Developing new, eco-friendly solvents which would meet technological and economic demands is perhaps the most popular aspects of Green Chemistry. Natural deep eutectic solvents (NADES) fully represent green chemistry principles. In this sense a new green vortex-assisted NADES-based microextraction (VA-NADES-ME) was established, for the first time, for the extraction of lamotrigine from human plasma samples using NADES, as a green extractant alternative to hazard organic solvents. Then extract was determined by high performance liquid chromatography with ultraviolet detection (HPLC–UV). The mixture of (choline chloride/ethylene glycol) as NADES was found to be the best candidate for extracting lamotrigine. Grey relational analysis-based Taguchi method was utilized as a chemometric protocol for multiobjective optimization of different HPLC performance parameters. The optimum mobile phase was a mixture of water with 0.3 % triethylamine in 0.02 M H3PO4 (adjusted to pH 5.5) and acetonitrile (70:30 v/v) with an overall pH 6. Finally, the confirmation test was performed to validate the predicted optimal results and established an improvement of 32.84 % from the initial design. The mobile phase was eluted in an isocratic mode with a flow rate of 0.8 mL/min and UV detection at 310 nm. The retention times of lamotrigine and tinidazole (internal standard) were 4.7 and 3.4 min, respectively. Proposed method was linear over the concentration range of 0.1–15.0 μg mL−1. The greenness profile was assessed using Analytical GREEnness metric approach which assured the greenness of the proposed method compared with other reported methods.

An Outlook to Six- and Pseudo Six-component Reactions in Organic Synthesis with a Glance at Some Aspects of Green Chemistry

In this review, we focused on the six- and pseudo-six-component transformations in organic syntheses as a class of important and applicable MCRs. Although the MCRs usage in recent years is enhanced the reports for more than five-component MCRs are still rare. In some cases, these kinds of MCRs are the combination of some tandem named reactions that generated a union MCR. Preparation of multi-functionalized heterocycles, prevention of intermediate separation, reaction progressing in a one-pot continuous manner, elevated total yield, high atom economy, and preparation of potent bioactive multi-cycles hetero-organics via the construction of several new bonds are some highlighted features of MCRs. In this article, we classified the mentioned sixcomponent reactions based on reaction media. Another subdivision is applied based on thermal energy usage or ambient temperature. In fact, two aspects of the green chemistry rules have been discussed.

Flow synthesis approaches to privileged scaffolds – recent routes reviewed for green and sustainable aspects

This review discusses the use of flow chemistry as versatile tool for the synthesis and derivatisation of privileged scaffolds, looking at applicability, diversity-oriented synthesis options, inherent sustainability and green chemistry aspects.

Efficient separation of precious metals from computer waste printed circuit boards by hydrocyclone and dilution-gravity methods

To fulfill the different aspects of green chemistry and to achieve full use of the secondary resources (waste printed circuit boards (WPCB)), the necessity of developing green methods for recovery of precious metals (Au, Pd, and Ag) is highly demanded. In this study, a novel environment-friendly physical separation approach; the combination of crushing, grinding, sieving as pretreatment steps alongside hydrocyclone and the dilution-gravity method (DGM) as the main final steps; is proposed. Inductively coupled plasma-mass spectrometry (ICP-MS), atomic absorption spectroscopy (AAS), and energy-dispersive X-ray spectroscopy (EDS) characterization methods were utilized to understand the effects of different separation steps applied in this research. The size and shape of grinded materials and the ones produced after hydrocyclone and DGM were evaluated using scanning electron microscopy. The results showed that the sieving step separated the highest gold fraction in the finer classification (<75 μm) while placed the copper (70 wt.%) into the coarser contents. The overflow to underflow outlet diameter ratio and inlet pressure was evaluated to determine the separation efficiency of a hydrocyclone effect of parameters. In the best-case scenario at 3 bar hydrocyclone operation pressure where the overflow to underflow outlet diameter (Do/Du) was 6.5, the highest metal fraction (87 wt.%) was achieved in the sink of the DGM. In this case, the total separation efficiency of gold, palladium, silver, and copper was 75%, 78%, 64%, 72%, respectively. Thus, this study demonstrates the feasibility of utilizing the sieving as mentioned above classification pretreatment steps followed by hydrocyclone and DGM methods as promising approaches for recovering precious metals from WPCBs that contain annually almost 50 million tons of e-waste.

Winning Strategy for Iron-Based ATRP Using In Situ Generated Iodine as a Regulator

Iron-based catalysts for atom-transfer radical polymerization (ATRP) are attractive in the sustainability aspects of green polymer chemistry but usually exhibit lower efficiency and controllability over the polymerization, as well as poorer tolerance to polar groups, compared to copper catalysts. Herein, β-ketamine/iron complexes, combining a strategy employing in situ generated iodine as a regulator, have been developed for improving the efficiency and robustness of iron-catalyzed ATRP. The catalyst system realizes low catalyst loading, ultrahigh molecular weight, robustness over polar groups, efficient polymerization of acrylate, and forthrightly synthesizing block copolymers, which are challengeable for common iron catalysts. A mechanism was proposed based on experimental results, which mainly involves the ATRP activation process by Fe(II) and the I2-mediated deactivation process.

Microsphere Polymers in Molecular Imprinting: Current and Future Perspectives.

Molecularly imprinted polymers (MIPs) are specific crosslinked polymers that exhibit binding sites for template molecules. MIPs have been developed in various application areas of biology and chemistry; however, MIPs have some problems, including an irregular material shape. In recent years, studies have been conducted to overcome this drawback, with the synthesis of uniform microsphere MIPs or molecularly imprinted microspheres (MIMs). The polymer microsphere is limited to a minimum size of 5 nm and a molecular weight of 10,000 Da. This review describes the methods used to produce MIMs, such as precipitation polymerisation, controlled/‘Living’ radical precipitation polymerisation (CRPP), Pickering emulsion polymerisation and suspension polymerisation. In addition, some green chemistry aspects and future perspectives will also be given.

Anthraquinones: Versatile Organic Photocatalysts

AbstractAnthraquinones (AQs) constitute the largest group of natural pigments, are commonly found in dyes, and are widely used in the textile industry due their photostability. They combine high absorptivity in the visible region with high excited‐state reduction potentials, making them effective acceptors of electrons and hydrogen atoms. AQs can be employed as organic catalysts in photooxidation reactions as well to produce reactive oxygen species (ROS). All these methods feature green chemistry aspects such as avoiding heavy metals, reducing waste, using inexpensive reagents, employing environmentally low‐impact solvents, and oxidizing with O2. This review covers the application of AQs in photoredox catalysis.

High Production Yield and More Thermally Stable Lignin-Containing Cellulose Nanocrystals Isolated Using a Ternary Acidic Deep Eutectic Solvent

From the aspects of green chemistry and sustainability, the use of green and sustainable materials and reagents for nanocellulose production is highly desirable. In this study, an acidic deep eutec...

Acacia gum versus pectin in fabrication of catalytically active palladium nanoparticles for dye discoloration

Obedience to the aspects of green chemistry and due to its high catalytic potency, ecofriendly synthesis of palladium nanoparticles (PdNPs) was performed using pectin versus acacia gum as polysaccharides. The viscous solution of alkali solubilized polysaccharides acted superiorly in stabilization of MNPs by decreasing their Brownian motions and sequentially decreased their collision and coagulation. Production of PdNPs preliminary was confirmed via UV–visible spectra. Zetasizer and transmission electron microscopy data, the particle size of PdNPs were prepared by pectin (27.9 nm) is larger than that by acacia gum (5.3 nm). XRD and FT-IR data affirmed the redox reaction between biopolymers and metal ions to produce PdNPs. PdNPs synthesized by acacia gum were characterized by higher surface area (19.54 m2/g) compared to that prepared by pectin (3.67 m2/g). Additionally, PdNPs synthesized by acacia gum were exhibited by fastest rate of dye discoloration, resulting in complete reductive discoloration of dye after only 5 min and t1/2 was estimated to be 1.70 min, while, k1 was 408.8 × 10−3 min−1. The presented green technique could be successively applicable for synthesis of size regulated catalytically active PdNPs to be employable in various industrial purposes.

An efficient strategy to synthesis of β-carbonyl compounds by 1-pentyl-1,2,4-triazolium methanesulfonate

It is well known that applying green chemistry aspects for organic reactions would reduce the toxicity of chemicals and it reduces the amount of volatile organic solvents too. Thus we have developed a Bronsted acidic 1-pentyl-1,2–4-triazolium methanesulfonate as a room temperature ionic liquid for organic reactions as reaction medium. The same has been employed as organocatalyst for the synthesis of β-Carbonyl Compounds. The present papers reveal the significance of ionic liquids in optimization of reaction condition in terms of equivalence of reagents, impact of solvents and amount of catalyst, synthesis of library of halogen rich β-carbonyl compounds.

Is Green Chemistry a feasible tool for the implementation of a circular economy?

The main goal of this research is to evaluate the contributions of Green Chemistry as a potential tool to drive the transition to circularity. For this, we have carried out a bibliographic study, analyzing those documents, process, or experiences that dealt jointly with the Green Chemistry aspects related to circularity such circular economy, industrial ecology, and closed loop. Findings show that few authors have treated that disciplines together in the last 10years. Based on an analysis of academic literature, common strategies (design, raw materials, life cycle assessment, processes, normative, new business, and collaboration), specific experiences (catalyst, biobased products or methods, recycling, and reusing), and difficulties to overcome (metrics, transdisciplinary research, unawareness, and competitiveness) have been identified. Finally, different kind of measures, as behind such joint metrics, informal open spaces, closer the industry, education, standards and label are proposed to facilitate the development of Green Chemistry, circular economy, industrial ecology, and closed loop with the ultimate goal of improving sustainable development.From the evidences found, we finally conclude that it is possible to use Green Chemistry and its principles as a tool to drive the transition to circularity, being the development of open spaces for exchange information between different actors from academia, governments and regulatory actors, business and industrial sectors, with the aim of promoting disruptive advances in sustainability.

Functionalized Silicas for Metal-Free and Metal-Based Catalytic Applications: A Review in Perspective of Green Chemistry.

Heterogeneous catalysis plays a key role in promoting green chemistry through many routes. The functionalizable reactive silanols highlight silica as a beguiling support for the preparation of heterogeneous catalysts. Metal active sites anchored on functionalized silica (FS) usually demonstrate the better dispersion and stability due to their firm chemical interaction with FSs. Having certain functional groups in structure, FSs can act as the useful catalysts for few organic reactions even without the need of metal active sites which are termed as the covetous reusable organocatalysts. Magnetic FSs have laid the platform where the effortless recovery of catalysts is realized just using an external magnet, resulting in the simplified reaction procedure. Using FSs of multiple functional groups, we can envisage the shortened reaction pathway and, reduced chemical uses and chemical wastes. Unstable bio-molecules like enzymes have been stabilized when they get chemically anchored on FSs. The resultant solid bio-catalysts exhibited very good reusability in many catalytic reactions. Getting provoked from the green chemistry aspects and benefits of FS-based catalysts, we confer the recent literature and progress focusing on the significance of FSs in heterogeneous catalysis. This review covers the preparative methods, types and catalytic applications of FSs. A special emphasis is given to the metal-free FS catalysts, multiple FS-based catalysts and magnetic FSs. Through this review, we presume that the contribution of FSs to green chemistry can be well understood. The future perspective of FSs and the improvements still required for implementing FS-based catalysts in practical applications have been narrated at the end of this review.

Introduction to cheminformatics for green chemistry education

Abstract The tools of cheminformatics are used for describing chemical structures for use in computer databases and in analyzing the connections between structure and molecular properties. As several aspects of Green Chemistry are also concerned with structure, properties and the relationships between them, cheminformatics provides tools that can be valuable in the teaching of Green Chemistry. This paper will provide an introduction to cheminformatics with a special emphasis on its value in chemical education and Green Chemistry.

Metal-supported and -assisted stereoselective cooperative photoredox catalysis.

In this perspective, we review those stereoselective photocatalytic reactions that use synergy between photoredox catalysts and transition metal catalysts. In particular, we highlight the orchestrated interaction between two and more metals which not only enhance the turnover numbers, but also lead to increased selectivities. Aspects of green chemistry and sustainable developments are included. In this review, C-C, C-O, C-N and C-S forming reactions are discussed and a perspective on future developments is given.

Evaluation of Green Sample Preparation Techniques for Organic Compounds

Nowadays, Green Analytical Chemistry (GAC) idea is of high importance, with impact on the rapid growth in the sample preparation area with special emphasis on sample preparation simplification, miniaturization and automation. Due to the fact that GAC is of high importance today, this study is focused on the evaluation of green sample preparation techniques for organic compounds. It is well known that sample preparation is considered a crucial part of analytical procedures, particularly in samples characterized by complex matrices composition. The parameter of “greenness” is as important as selectivity in order to avoid using harmful organic solvents in sustainable extraction techniques. These solvents can generate hazardous, toxic waste while consuming large resources volume, thus, developing new, eco-friendly and benign solvents which would meet technological and economic demands is perhaps the most popular aspects of Green Chemistry. Some examples of these “green” solvents are given in this work. In addition, several new miniaturized extraction techniques are described. Here you can highlight solid phase microextraction (SPME) and liquid phase microextraction (LPME). However, the best option would be to use direct methods of analysis, where sample preparation is not required. The given study also shows the possibilities and limitations of using Eco-Scale and GAPI tools for the assessment of the green character of selected analytical procedures. Both tools were applied to assess 9 different analytical procedures and both showed similar results presented in a different manner.

Aspects of Green Chemistry Towards Synthesis of Biologically Active Substituted Benzoxazinones

Aspects of Green Chemistry Towards Synthesis of Biologically Active Substituted Benzoxazinones

Hydrotalcite as Active and Selective Catalyst for Synthesis of Dehydrozingerone from Vanillin and Acetone: Effect of Catalyst Composition and Calcination Temperature on Activity and Selectivity

Background: Dehydrozingerone is a biosynthetic intermediate and structural analog of curcumin. It is a flavoring ingredient and has antioxidant and antimutagenic properties. Dehydrozingerone can be efficiently synthesized from vanillin and acetone by cross-aldol (or Claisen-Schmidt) condensation using heterogeneous base catalysts. Vanillin can be sourced from the valorization of biomass. Green chemistry aspects such as 100 % atom economy and low E factor are very important in any synthesis which could be achieved by use of heterogeneous catalysis. Keywords: Biomass, vanillin, hydrotalcite, dehydrozingerone, cross-aldol (or Claisen-Schmidt) condensation.

Natural Deep Eutectic Solvents in Extraction Process

Developing new, eco-friendly solvents which would meet technological and economic demands is perhaps the most popular aspects of Green Chemistry. Natural deep eutectic solvents (NADES) fully meet green chemistry principles. These solvents offer many advantages including biodegradability, low toxicity, sustainability, low costs and simple preparation. This paper provides an overview of knowledge regarding NADES with special emphasis on extraction applications and further perspectives as truly sustainable solvents.

Green polymer chemistry: new methods of polymer synthesis using renewable starting materials

The present article reviews the recent results reported mainly from our group on “green polymer chemistry”. Characteristic important aspects of green polymer chemistry include herein, typically (1) using renewable resources as starting materials for polymer production, and (2) employing green method for the polymer synthesis. As renewable starting materials, the following materials were employed; lactic acid, itaconic anhydride, renewable plant oils, and cardanol. Polymer production using these materials contributes to mitigate the carbon dioxide emission because of their “carbon neutral” nature. As green method, lipase enzyme was mainly used for polymerization catalyst, since lipase is a natural benign catalyst, showing a specific catalysis as well as recyclable character. Polymer synthesis from these materials and the catalyst provided various value-added functional polymers, demonstrating good examples of green polymer chemistry.

A Mild and Selective Method for the Catalytic Hydrodeoxygenation of Cyanurate Activated Phenols in Multiphasic Continuous Flow

A low-energy, high-selectivity approach to the catalytic hydrodeoxygenation of phenols is reported using batch or continuous flow methods to react 3 equiv of phenol with cyanuric chloride then hydrogenolyzing the triarylcyanurate intermediate to give 3 equiv of deoxo aromatic. The use of cyanuric chloride compares favorably with existing activation methods, showing improved scalability, atom efficiency, and economics. The scope of both the activation and hydrogenolysis stages are explored using lignin-related phenols. Initial development has identified that continuous stir tank reactors (CSTRs) enable a multiphasic process for converting guaiacol to anisole and at steady state overcome the catalyst deactivation issues observed in batch, seemingly caused by the cyanurate byproduct. Green chemistry aspects and the potential for industrial adoption are discussed.