Use Of Hazardous Organic Solvents Research Articles

Green synthesis of positive electrodes for high performance structural batteries - A study on graphene additives

Carbon fibres (CF) have the potential to serve as versatile and multifunctional conductive electrodes within the concept of “structural batteries”. These batteries possess the unique ability to both store electrical energy and bear mechanical loads without requiring extra current collectors. However, numerous challenges remain on the path to commercializing structural batteries. One significant challenge lies in the fabrication process of CF-based cathode composites, including the poor adhesion of active materials to the CF surface and the use of hazardous organic solvents, such as N-methyl pyrrolidone (NMP) through traditional blade coating. In this study, we present a sustainable fabrication approach, using electrophoretic deposition (EPD) to construct positive electrode composites with lithium iron phosphate (LiFePO4) and graphene nanosheets. Especially, ethanol was used as a green solvent replacing NMP to minimize the environmental impact. Meanwhile, the influence of different types of graphene additives (three kinds of graphene nanoplatelets (GNP), four kinds of reduced graphene oxide (rGO) and one home-made graphene) to the relative battery performance were evaluated under a systematic comparative analysis. Among the tested graphene additives, LFP/rGO2 based positive electrode exhibits a desirable specific capacity of 126.2 mAhg−1, maintaining over 93% retention even under the demanding conditions of 2C over 500 cycles.

Combined green analytical principles and quality by design for ultraperformance liquid chromatography analytical method development, the characterization and in-silico toxicity prediction of Ixazomib degradation products using mass spectrometry

Ixazomib citrate (IC) is the first oral selective proteosome inhibitor for treating multiple myeloma. IC is prone to degradation due to its oxidative deboronation and the amide bond, affecting patient health, drug quality, and efficacy. The stability of IC is crucial during drug development as it guides the inherent stability of the molecule, its degradation pathways, packing materials, and formulation development. Following the International Conference on Harmonization (ICH) Q1A (R2) and Q1B, a stability study were performed for both solution and solid-state stress studies. Under oxidative and alkaline conditions, 3 degradation products (DPs) were identified, separated, and method-validated according to ICH Q2 (R1) guidelines. From the Design Expert statistical tool, the Central Composite Design was used to optimize the final analytical method conditions, where the p-values for the model are < 0.05%. Green analytical chemistry has significantly reduced the use of hazardous organic solvents without losing chromatographic performance. The green separation and quantification of DPs and IC on Ultra Performance Liquid Chromatography (UPLC) using an Inert-Sustain C8 (50×3.0) mm 2.0 µm column with gradient elution using 10 mM ammonium acetate buffer (pH 5.0) and ethanol at a flow rate of 0.5 mL/min and detection at 230 nm. The results of green assessment tools like GAPI, AGREE, and Analytical eco-scale found that the method is excellent for the greenness of utilizing ethanol as a solvent, shorter runtime, and lesser waste. The method was validated as per ICH Q2 guidelines, and the results found it is sensitive, precise, accurate, robust, and linear for its intended use. The method is suitable for quantifying IC and its DPs from 2.0 to 150 µg/mL with R2 values of 0.9996 with a detection limit of 1.0 µg/mL. The plausible degradation structures and pathways of DPs were outlined using tandem mass spectra employed on LC-QTOF-MS/MS in both ESI positive and negative modes. The mechanistic explanation for establishing DPs was explained in detail. The ADMET Predictor™ software predicted the physicochemical and ADMET properties. The toxicity profile reveals that DP2 and DP3 are teratogenic, while D1 and D3 show phospholipidosis.

Solvent-free parallel artificial liquid membrane extraction for drugs of abuse in plasma samples using LC-MS/MS

BackgroundParallel artificial liquid membrane extraction (PALME) is a 96-well plate setup variant of liquid-phase microextraction. Basic or acidic analytes are extracted in neutral form from the sample, through a supported liquid membrane (SLM), and into aqueous acceptor. PALME is already considered a green extraction technique, but in the current conceptual work, we sought to make it even greener by replacing the use of organic solvents with essential oils (EO). PALME was combined with LC-MS/MS for analysis of plasma samples and multiple drugs of abuse with toxicological relevance (amphetamines, phenethylamines, synthetic cathinones, designer benzodiazepines, ayahuasca alkaloids, lysergic acid diethylamide, and ketamine). ResultsFourteen EO were compared to organic solvents frequently used in PALME. The EO termed smart & sassy yielded the best analyte recovery for all drugs studied and was thus selected as SLM. Then, factorial screening and Box-Behnken were employed to optimize the technique. The extraction time, concentration of base, sample volume, and percentage of trioctylamine significantly impacted analyte recovery. The optimum values were defined as 120 min, 10 mmol/L of NaOH, 150 μL, and 0%, respectively. Once optimized, validation parameters were 1–100 ng mL-1 as linear range, accuracy ±16.4%, precision >83%, 1 ng mL-1 as limit of quantitation, 0.1–0.75 ng mL-1 as limit of detection, matrix effect <20%, and recovery 20–106%. Additionally, EO purchased from different production batches were tested and achieved acceptable reproducibility. Data were in compliance with requirements set by internationally accepted validation guidelines and the applicability of the technique was proven using authentic samples. SignificanceIn this study, the use of an EO provided a solvent-free sample preparation technique suited to extract different classes of drugs of abuse from plasma samples, dismissing the use of hazardous organic solvents. The method also provided excellent sample clean-up, thus being a simple and efficient tool for toxicological applications that is in agreement with the principles of sustainable chemistry.

A novel thermoplastic water-soluble sizing agent for the interfacial enhancement of carbon fiber/polyether ether ketone composites

Recently reported novel water-soluble polyether ether ketone (PEEK) derivative sizing agents have garnered considerable attention for improving interfacial bonding of carbon fiber-reinforced PEEK (CF/PEEK) composites. However, their extensive application is somewhat limited due to two drawbacks: the use of hazardous organic solvents in production and the retention of emulsifiers in sizing dispersion systems. Herein, an extremely hydrophilic sulfonated PEEK with a cardo group (S-PEEK-WC) was synthesized and used to prepare a water-soluble sizing agent. The S-PEEK-WC exhibits excellent thermal stability, with a 5 % decomposition temperature of 446.5 °C, and its aqueous solution remains stable for over six months. A robust interphase was also constructed in the CF/PEEK composites through multiple physicochemical interactions. Compared with the de-sized CF/PEEK composites, the interlaminar shear strength, flexural strength and interfacial shear strength of the CF2/PEEK composites improved by 57.9 %, 56.3 % and 44.8 %, respectively. This approach may shed some light on the development of a valid and environmentally friendly method for preparing water-soluble sizing agents of polyaryletherketone.

Effect of solvent-free membranes-forming processes on HT-PEM properties of highly soluble polybenzimidazole

The cost-effective sol-gel process for the preparation of phosphoric acid (PA) doped P-PBI membranes using PPA as both condensation reagent and solvent could avoid the use of hazardous organic solvents. However, optimizing the trade-off effect between mechanical properties and proton conductivity of sol-gel membranes by increasing polymer content is ineffective due to the limited solubility of P-PBI in PPA. Herein, we successfully fabricated a series of sol-gel membranes with tunable properties using a highly soluble polybenzimidazole (N-PBI). In addition, the sol-gel (5 wt%) N-PBI membrane was further specially dried and post-doped with PA to obtain a re-doped sol-gel N-PBI membrane. Therefore, the properties of PA-doped N-PBI membranes fabricated using three different processes-conv, sol-gel, and re-doped sol-gel-were thoroughly characterized. The sol-gel N-PBI membranes demonstrated a dependence of mechanical properties and proton conductivity on polymer content, with a maximum tensile strength of 7.0 MPa at 7 wt% polymer content and a maximum proton conductivity of 205 mS/cm (200 °C) at 2 wt% polymer content. The ADL-controlled re-doped sol-gel N-PBI membrane achieved higher saturated ADL than the sol-gel N-PBI membrane, resulting in higher proton conductivity and fuel cell performance. The sol-gel (2 wt%) N-PBI membrane exhibited an ultra-high H2/O2 peak power density of 1058 mW/cm2 under an optimized operating condition, and the sol-gel (7 wt%) N-PBI membrane achieved stable operation without apparent degradation for over 2000 h at 160 °C with 0.3 A/cm2 current density.

DoE-enhanced development and validation of eco-friendly RP-HPLC method for analysis of safinamide and its precursor impurity: QbD approach

Design of Experiment (DoE) is an effective methodology for studying the relationship between variables and their dependent responses. In this study, DoE was employed for method development and optimization. A binary combination of safinamide mesylate (SAF) and its synthetic precursor p-hydroxybenzaldehyde (PHB) were analyzed by RP-HPLC. Method development focused on evaluating the effect of three independent factors; % EtOH, pH, and flow rate; on performance and efficiency of separation. A rotatable central composite design (CCD) was applied to determine crucial variables and optimize key performance parameters.Significant interest has been shown in green analytical chemistry as a means to reduce the use of hazardous organic solvents without degrading chromatographic performance. A green separation and quantification were performed using a Waters VDSpher PUR 100 C18-E column (5 µm, 250 × 4.6 mm) at a flow rate of 1 mL/min, utilizing abinary combination of mobile phase A: B (60:40, v/v). Phase A of the mobile phase consisted of 0.02 M ammonium formate and 0.02 M ammonium acetate, with the pH adjusted to 5.5 using formic acid. EtOH was utilized as mobile phase B, and 20 µL was employed as the injection volume. The technique was validated in accordance with ICH criteria. SAF had a linear range of 4–100 µg/mL, while PHB had a linear range of 0.2–10.0 µg/mL. Both analytes had R2 values of 0.9999, with detection limits of 0.95 and 0.06 µg/mL, respectively. The designed method could be applicable for regular QC analysis of SAF and its pharmaceutical product. GAPI and AGREE algorithms, which use 12 principles of green analytical chemistry, were used to evaluate the method greenness.

Deep eutectic solvents with low viscosity for automation of liquid-phase microextraction based on lab-in-syringe system: Separation of Sudan dyes

In the work limitations of deep eutectic solvents in the flow-based analysis are discussed. Deep eutectic solvents based on terpenes and fatty acids with low viscosity were studied as extraction solvents for liquid-liquid microextraction into a lab-in-syringe system for the first time. As a result an automated deep eutectic solvent-based microextraction approach was proposed. The procedure involved aspiration of deep eutectic solvent (based on terpene and fatty acid) and aqueous sample solution followed by phases mixing by a magnetic stirrer inside a syringe of flow system. After phase separation the extract phase was transferred from the syringe into a vial followed by analysis by a high-performance liquid chromatography with diode-array detection. The determination of Sudan I, Sudan II and Sudan III in chili-based sauces was considered as an analytical task. The mass-transfer intensification performed by the magnetic stirring inside the syringe allowed to perform fast (2 min) and efficient (extraction recoveries 87–95%) extraction. The limits of detection, calculated from a blank test based on 3σ, were from 0.003 to 0.005 mg kg−1, RSD was <9%. The microextraction procedure did not involve the use of hazardous organic solvents, only 100 μL of natural deep eutectic solvent was required for dyes preconcentration.

Electrodialytic Universal Synthesis of Highly Pure and Mixed Ionic Liquids.

Ionic liquids (ILs) have attracted significant attention from researchers in various fields as a result of their unique properties. As new and important applications are identified for these materials, there is also a drive to develop methods for accessing a wider range of ILs. However, despite this demand, only a few techniques have so far been reported and, more importantly, general but efficient processes for IL synthesis have been lacking. Thus, it would be beneficial to devise a cost-effective, environmentally friendly means of producing a wide variety of pure ILs. The present work demonstrates a general purpose electrodialysis approach to the formation of highly pure ILs, based on the formation of nine different ILs from various combinations of cations and anions. In each case, the IL is obtained with a purity of greater than 99%. This method offers the advantages of avoiding the use of hazardous organic solvents and eliminating tedious and costly purification processes. Unlike conventional methods, this membrane-based technology also prevents the generation of side products. Mixed ILs have many potential applications, and the present technique readily generates various mixed ILs based on a simple adjustment of the applied current.

Extraction of Bioactive Compounds From Cannabis sativa L. Flowers and/or Leaves Using Deep Eutectic Solvents

The increasing demand for medical cannabis urges the development of new and effective methods for the extraction of phytocannabinoids. Deep eutectic solvents (DESs) are an alternative to the use of hazardous organic solvents typically used in the industry. In this study, hydrophilic and hydrophobic DESs were developed based on terpenes, sugars, and natural organic acids as green extraction media for the extraction of cannabis bioactive compounds. The factors influencing the extraction of bioactive components, such as the type of DESs and extraction time, were investigated. Initial screening in hemp showed that the DES composed of Men: Lau (a 2:1-M ratio) had a greater extraction efficiency of cannabidiol (CBD) and cannabidiolic acid (CBDA) (11.07 ± 0.37 mg/g) of all the tested DESs and higher than ethanol. Besides having a higher or equivalent extraction yield as the organic solvents tested, DESs showed to be more selective, extracting fewer impurities, such as chlorophyll and waxes. These results, coupled with the non-toxic, biodegradable, low-cost, and environmentally friendly characteristics of DESs, provide strong evidence that DESs represent a better alternative to organic solvents.

Chemical-Free Dyeing of Cotton With Functional Natural Dye: A Pollution-Free and Cleaner Production Approach

This study is a novel approach toward the development of a chemical-free and sustainable textile dyeing process with minimum environmental risks. Cotton fabrics were cationized with (3-chloro-2-hydroxypropyl) trimethylammonium chloride in four concentrations and subsequently dyed with the black tea extract. Eco-friendly colorant extraction from raw black tea leaves was carried out in aqueous media avoiding the use of hazardous organic solvents. The major coloring components in the black tea extract are polyphenols like theaflavins and thearubigin. Cationized cotton fabrics were dyed in four different shade depths without employing auxiliary chemicals in the dyeing process. For comparison, un-cationized cotton was dyed with the same extract in the same shades. It was observed that un-cationized cotton samples exhibited very low color strength (K/S) values and excellent colorfastness rating. However, the cationized samples showed remarkable enhancement in their color strength with an increase in the concentration of the cationizing agent. Furthermore, colorfastness to washing, rubbing, and perspiration was excellent, but lightfastness was poor. Deep shades (K/S = 8.996) were obtained for cotton sample cationized (20 g/l) and dyed (6%) shades. Thus, the extraction of natural colorants without toxic solvents, economically viable surface modification of cotton, and chemical-free dyeing render the dyeing process cleaner, sustainable, and practicable at an industrial scale. The textile units could easily adopt this approach to regulate a pollution-free dyeing process without modifying their existing infrastructure.

Green Stability Indicating Organic Solvent-Free HPLC Determination of Remdesivir in Substances and Pharmaceutical Dosage Forms

A green liquid chromatographic method is considered in this work to minimize the environmental impact of waste solvents. One important principle is to replace or eliminate the use of hazardous organic solvents. Organic impurities in any active pharmaceutical ingredient could arise either during the process of its synthesis, or as degradation products developed throughout the shelf-life. Remdesivir (RDS) is an antiviral drug, approved by the US Food and Drug Adminstration (-FDA), to treat SARS-Cov-2 virus during its pandemic crisis. We studied the stability of remdesivir against several degradation pathways using the organic solvent-free liquid chromatographic technique. Separation was performed on RP-C18 stationary phase using mixed-micellar mobile phase composed of a mixture of 0.025 M Brij-35, 0.1 M sodium lauryl sulfate (SLS), and 0.02 M disodium hydrogen phosphate, adjusted to pH 6.0. The mobile phase flow rate was 1 mL min−1, and detection was carried out at a wavelength of 244 nm. We profiled the impurities that originated in mild to drastic degradation conditions. The method was then validated according to International Conference of Harmonization (ICH) guidelines within a linearity range of 5–100 μg mL−1 and applied successfully for the determination of the drug in its marketed dosage form. A brief comparison was established with reported chromatographic methods, including a greenness assessment on two new metrics (GAPI and AGREE). This study is the first to be reported as eco-friendly, solvent-free, and stability indicating LC methodology for RDS determination and impurity profiling.

Microwave-assisted Organic Synthesis in Water

Most of the traditional methods for organic synthesis have been associated with environmental concern. The transition from traditional to modern methods of synthesis is mainly based on principles of green chemistry to achieve better sustainability by reducing the negative impact on the environment and health. It has been found that the use of microwaves as an energy source in organic synthesis has a great advantage over conventional heating. Microwave-assisted reactions are energy efficient and hence, are being considered in the preview of the green chemistry principles. The use of safer solvents is another important principle of green chemistry. The use of water as a solvent in organic synthesis has great benefits over the use of hazardous organic solvents in terms of environment and safety. This compilation will cover the use of both microwave and water simultaneously in organic reactions.

Antisolvent‐Free Fabrication of Efficient and Stable Sn–Pb Perovskite Solar Cells

Pb‐based perovskite solar cells (PSCs) have shown great potential in next‐generation photovoltaics. However, the toxicity of Pb remains a big concern. Partial replacement of Pb with Sn is shown to reduce the toxicity of PSCs without considerably compromising the device performance. Currently, Sn–Pb single‐junction PSCs have realized a champion power conversion efficiency (PCE) of 21.7%, whereas all perovskite tandem PSCs with a Pb–Sn device as the bottom cell have achieved a PCE of 25.5%. However, the fabrication process of Sn–Pb PSCs is still not ecofriendly due to the use of hazardous organic solvents and antisolvents. Herein, for the first time, a one‐step antisolvent‐free method is developed to fabricate a high‐quality Sn–Pb perovskite film using methylammonium acetate (MAAc) ionic liquid as a green solvent. The crucial effects of multiple organic halides (MOHs) on the crystallization process and characteristics of the Sn–Pb film are comprehensively investigated. After optimizing the film fabrication parameters, PSCs with a champion PCE of 15.42% can be achieved. Moreover, the device exhibits robust stability that shows negligible PCE loss after being stored in N2 for 720 h. A new avenue to promote the ecofriendly fabrication of efficient Sn–Pb PSCs is opened up.

Green and Scalable Preparation of Colloidal Suspension of Lignin Nanoparticles and Its Application in Eco-friendly Sunscreen Formulations.

Lignin nanoparticles (LNPs) are applied in several industrial applications. The nanoprecipitation of LNPs is fast and inexpensive but currently still limited to the use of hazardous organic solvents, making it difficult to apply them on a large scale. Here, we report a scalable nanoprecipitation procedure for the preparation of colloidal lignin nanoparticles (cLNPs) by the use of the green solvents dimethylisosorbide and isopropylidene glycerol. Irrespective of the experimental conditions, cLNPs showed higher UV absorbing properties and radical scavenging activity than parent LNPs and raw lignin. cLNPs were successively used in the preparation of eco-friendly sunscreen formulations (SPF 15, 30, and 50+, as evaluated by the COLIPA assay), which showed high UV-shielding activity even in the absence of synthetic boosters (microplastics) and physical filters (TiO2 and ZnO). Biological assays on human HaCaT keratinocytes and human skin equivalents demonstrated the absence of cytotoxicity and genotoxicity, associated with an optimal protection of the skin from UV-A damage.

On the organic solvent free preparation of ultrafiltration and nanofiltration membranes using polyelectrolyte complexation in an all aqueous phase inversion process

Sustainable polymeric membrane fabrication aims for processes without the use of hazardous organic solvents or crosslinkers. One promising alternative method represents the fabrication of polyelectrolyte complex (PEC) membranes based on aqueous phase separation. We present the fabrication of PEC membranes from salt dilution induced phase separation. The complexation of the polyanion PSS and polycation PDADMAC is suppressed by an overcritical KBr concentration. The overcritical liquid polymer solution is cast and subsequently immersed in deionized water. The concentration gradient leads to salt diffusion out of, and water into the liquid polymer solution until the composition enters the demixing gap. Further salt dilution induces polyelectrolyte precipitation in the two phase region and forms the final porous PEC membrane. The presented approach shows similarities to the established non-solvent induced phase separation (NIPS), so high potential for the transfer of existing expertise. Most notably, the influence of simultaneous demixing of polyions is observed for different polyanion/polycation ratios in the liquid polymer solution. Three monomer ratios lead to membranes with different morphologies and separation properties in the range of ultrafiltration and nanofiltration. The presented method can be applied with commercially available polyelectrolytes and is easy to implement. This method is a promising approach to eliminating the use of organic solvents and realizing a sustainable alternative to the state of the art polymeric membrane fabrication processes.

Bisindolization Reaction Employing Phthalimide-N-sulfonic Acid as an Efficient Catalyst

Background: Bis(indolyl) methanes (BIMs) have a wide spectrum of applications in biomedicine and agriculture as well as are present in natural products. These bisheterocyclic compounds possess vast pharmacological, including antifungal, antitubercular, anti-inflammatory, antibacterial, anticancer, anticonvulsant, antibiotic, antiviral, antimalarial, analgesic, and antidiabetic properties. BIMs scaffolds have also been employed as selective optical chemosensors for detection of some anions and cations with the naked eye. Because of the importance of these bisheterocycles, various methods have been reported for their synthesis through reaction of indole derivatives and aldehydes or ketones. Therefore, the synthesis of BIMs through different methodologies has received widespread attention in the field of organic synthesis and medicinal chemistry. Objective: In this study, the catalytic activity of phthalimide-N-sulfonic acid (PISA) as an efficient and safe solid acidic organocatalyst toward the synthesis of BIMs derivatives in ethanol is described. Methods: Indole derivatives (2 mmol), aryl/heteroaryl aldehydes (1 mmol), and PISA (10 mol%) were mixture in ethanol. The reaction mixture was stirred at room temperature for the appropriate times. After workup and separation of catalyst, the corresponding heterocyclic products were obtained through recrystallization from hot ethanol. Results: The BIMs derivatives were easily obtained via Bisindolization Reaction (BIR) of two indoles (2-methylindole and indole) with a series of aryl and heteroaryl aldehydes. The BIR was efficiently catalyzed at room temperature using PISA as an excellent organocatalyst under optimized reaction conditions. Conclusion: The reactions were implemented in simple manner and were completed within acceptable reaction times. The expected BIM products were obtained in satisfactory yields. The catalyst can be recovered and reused several times in the template reaction. This approach provides the benefits of convenience, simple operational procedure, no use of hazardous organic solvents, cheapness and ease of preparation of catalyst.

Solvent-free synthesis of 1-amidoalkyl-2-naphthols using magnetic nanoparticle-supported 2-(((4-(1-iminoethyl)phenyl)imino)methyl)phenol Cu (II) or Zn (II) Schiff base complexes

Two magnetic nanoparticle-supported 2-(((4-(1-iminoethyl)phenyl)imino)methyl)phenols were successfully synthesized, characterized, and applied in the one-pot three-component reaction of substituted benzaldehydes, 2-naphthol, and amides for synthesis of 1-amidoalkyl-2-naphthols. These three-component processes occurred under solvent-free reaction conditions at 80 °C. The magnetically recoverable supported Schiff base metal catalysts can be reused several times in the model reaction. The synthesized catalysts are also easily separated from the reaction mixture by applying an external magnet. This procedure offers the advantages of simple, operational procedure as well as no use of hazardous organic solvents.

A green synthesis of quinoline‐4‐carboxylic derivatives using p‐toluenesulfonic acid as an efficient organocatalyst under microwave irradiation and their docking, molecular dynamics, ADME‐Tox and biological evaluation

AbstractP‐Toluenesulfonic acid, being an efficient, nonhazardous, and fast accessible organocatalyst, was used for the preparation of quinoline‐4‐carboxylic acid derivatives via a one‐pot three‐component reaction of aromatic benzaldehyde, substituted aniline, and pyruvic acid under microwave irradiation. After completion of the reaction, the pure products were isolated by column chromatography. Here, to achieve the desired synthesis, various catalytic and solvent conditions were applied to perform a comparison study. We are using higher yield, simple work‐up process, avoiding the use of hazardous organic solvents, short reaction time and higher advantages of the present protocol in the study. Biological activities of synthesized compounds were tested against various antibacterial, antifungal, antimalarial, and antituberculosis strains. Compounds 4a and 4c (MIC 50 μg/mL) and compounds 4d and 4n (MIC 62.5 μg/mL) were found active against the Escherichia coli strain, compounds 4c and 4p (MIC 25 μg/mL) were found active against the Staphylococcus aureus strain, and compounds 4c and 4d were found active against the Plasmodium falciparum strain. Molecular docking revealed that ligands and proteins fitted exactly in the binding pocket and had significant correlation with the biological activity. We have also tested molecular dynamics and ADME‐Tox parameters for the synthesized compounds.

Expeditious synthesis and kinetic study of biodegradable amide 2,2-( (3-(2-((carboxymethyl)amino)-2-oxoethyl)-3-hydroxypentanedioyl)bis(azanediyl) diacetic acid (COHBDA) under ultrasound irradiation

ABSTRACT The amide bond formation has vital importance in chemical synthesis and industry. Amidation reaction with atom economic efficiency is the greatest demanding due to the use of hazardous coupling agent and intolerable waste by product in the reaction. Hence looks forward to its development in a more sustainable approach. In answer to this intense demand, we here in reveal an economically simple and environmentally friendly expeditious one-pot synthesis of biodegradable amide 2,2-( (3-(2-((carboxymethyl)amino)-2-oxoethyl)-3-hydroxypentanedioyl)bis(azanediyl)diacetic acid (COHBDA) by the reaction of glycine and citric acid in aqueous media. To address the green synthetic protocol, reaction has been carried out under ultrasound irradiation in an aqueous medium to avoid the use of hazardous organic solvents to make the procedure easier and greener. The influence of various reaction parameters such as agitation speed, temperature and pH were studied. A kinetic model revealed that the amidation reaction of glycine and citric acid can be well explained by the second order reaction.

Greener and efficient synthesis of Benzodiazepines using mixed Ferrite under solvent free condition

The Ferrite material Zn0.6Ni0.2Cu0.2Fe2O4 was synthesized by the sol-gel auto combustion method and characterized by its TG and DTA. The crystallographic structures were studied by XRD. Morphology and structure of the powder samples were studied by SEM and TEM. The synthesis of benzodiazepines via one-pot two-component condensation reaction of o-phenylene diamine and ketones carried by using synthesized ferrite as a recyclable catalyst. This synthetic approach eliminates the use of hazardous organic solvents with the important benefit of easy separation and reusability of the catalyst without compromising the yield or purity