ABSTRACTThe photocatalytic degradation of the organic pollutants using the green synthesized catalysts is an environmentally safe approach for the wastewater treatment. In this study, ZnO and CuO nanoparticles (NPs) and ZnO/CuO nanocomposites (NCs) with various CuO weight percents were synthesized using extract of Musa acuminata fruit peel as the stablizing and capping agent. The synthesized nanomaterials were characterized by TGA/DTA, XRD, SEM, TEM, SAED, HR-TEM, UV-DRS and FTIR techniques. The degradation of methylene blue (MB) dye using the synthesized catalysts was investigated under a visible light source. XRD analysed average crystalline sizes were 24.9, 17.0 and 22.6 nm for ZnO, CuO, and ZnO/CuO nanomaterials, respectively. The SEM and TEM analysis confirms that ZnO NPs, CuO NPs, and ZnO/CuO NCs possessed the spherically shaped monoclinic structure. The bandgap energies (Eg)(Eg)(Eg) of ZnO NPs, CuO NPs and ZnO/CuO NCs were found to be 3.25, 1.7 and 3.18 eV respectively. The FT-IR analysis confirms presence of various reducing and capping agents. The photocatalytic activities of ZnO NPs, CuO NPs, and ZnO/CuO NCs were evaluated using the degradation of MB dye under the visible light irradiation. The photocatalysts CuO, ZnO, and ZnO/CuO exhibited the degradation efficiencies of 50%, 57%, and 90%, respectively.

ABSTRACTThe present study aimed to separate the three-drug combination and degradant products by applying stress studies in bulk and pharmaceutical using RP-HPLC green analytical chemistry principles to make the separation better and more effective without compromising the standard limits. The three drugs have separated using the Mobile Phase Mixture of 10 volumes of buffer (0.1% triethanolamine in water) and 90 volumes of ethanol on the stationary phase Inertsil ODS 3 (250 mm x 4.6 mm), 5 µm column, at a wavelength of 256 nm. The method has been performed on a linear concentration range of 12–28 µg/mL for ATR, EZB, and 192- 448 µg/mL for FNF. The forced degradation studies showed that the ATR had > 5% degradation in acid, peroxide and thermal degradation, as EZB tends to degrade more than 15% at alkali hydrolysis. Moreover, the methodology has been validated according to ICH Q2 R1 guidelines, assessed using green evaluation tools like GAPI, AES, and AGREE, and found eco-friendly according to the output of the greenness outcomes. The developed method employed for determining three drugs has shown within limits according to the guidelines, easily adaptable by the pharmaceutical industries for their regular quality control analysis of the combinations.

ABSTRACTA perspective on incorporating the United Nations Sustainable Development Goals (UNSDG) and Green Chemistry Principles (GCP) into high school chemistry curricula is presented. The framework is based upon the Johnstone-Mahaffy model for chemistry understanding which specifically links student learning to the affective or human-centred domain. Reference is made to the origins of high school chemistry curricula, recommendations from the recent Royal Society of Chemistry survey Green Shoots: A Sustainable Chemistry Curriculum for a Sustainable Planet, student engagement practices, and studies in adolescent mental health. The origins and organization of the UNSDG and GCP are outlined, with the similarities to high school chemistry curricula illustrated. Justification for the implementation of the UNSDG and GCP is given, with a specific example presented in the context of the International Baccalaureate chemistry curriculum, and the GCP are rendered in educator- and student-appropriate language.

ABSTRACTThis paper describes the design and implementation of a political advocacy project in an Organic Chemistry II course. The advocacy project was designed to demonstrate that organic, green, and sustainable chemistry can be applied outside of laboratory and industrial settings to help solve issues related to environmental sustainability. After the instructor identified pending state legislation relating to sustainability, students read and summarized the bill. After class discussion, students did further research into questions raised in the discussion and prepared talking points. The talking points were developed into a white paper or postcard in advance of a class trip to the state capitol to share the views with legislators. Student reflections indicated a positive experience with advocacy, a greater understanding of environmental issues that affect them, and better awareness of how they can affect change.

ABSTRACTA novel and highly efficient electro-catalytic protocol for the synthesis of cyclic carbonates from epoxides and CO2 using 1-aminopropyl-3-methylimidazolium dicyanamide ([APMIm]DCA) as the supporting electrolyte, graphite as the anode, and Ti/TiO2-CNT-Pt as the cathode has been developed. Based on the cooperative effect between active Ti/TiO2-CNT-Pt cathode and active sites of supporting ionic liquid electrolyte [APMIm]DCA, CO2 and epoxides could be effectively converted into the corresponding cyclic carbonates in high to excellent yields under mild conditions. Moreover, the electro-catalytic system could be easily recovered and reused for six successive cycles without a considerable decrease in catalytic activity. This work provides a sustainable and efficient cooperative strategy for the chemical fixation of carbon dioxide into valuable cyclic carbonates.

ABSTRACTThis paper addresses the development and evaluation of a case study designed to introduce both the core chemistry concepts of oxidation and reduction reactions as well as green chemistry within the undergraduate organic chemistry curriculum. The developed case study consisted of two parts that can be used in tandem or independently. Part 1 focused on calculating oxidation states and determining whether the provided bioderived reactions represented oxidation or reduction reactions, and Part 2 focused on evaluating the greenness of oxidation reactions. Students reported positive learning gains for both the core chemistry concepts of oxidation and reduction reactions and green chemistry and reported that they viewed the case study favorably. It is our hope that other educators use this case study module to incorporate green chemistry into their organic courses and use its development as inspiration to create further case studies that integrate green chemistry into the curriculum.

ABSTRACTThis study aims to biosynthesize zinc oxide nanoparticles using aqueous leaf extracts of Cnidoscolus aconitifolius and investigate their biological activities. UV–Vis Spectroscopy, FT-IR, SEM and TEM were used for characterization. The antioxidant properties were determined using H2O2, NO, ABTS, FRAP and DPPH scavenging assays. For anti-inflammatory activities, membrane stabilization, albumin denaturation and proteinase inhibitory activity were assayed. The antibacterial effect was tested using well diffusion method. Statistical analyses were done using ANOVA. Synthesized nanoparticles showed an intensity peak at 378 nm in UV–Vis Spectroscopy. FT-IR shows the presence of O-H stretching, C = C bending, O-H bending and C–N stretching functional groups of the stabilizing action of the plant extract on the surface of the nanoparticles. NPs were shown to be spherical by SEM analysis, and the sizes were 100 nm by TEM analysis. The antioxidant properties of ZnO NPs compared to ascorbic acid standard showed significant antioxidant potential in H2O2, NO, ABTS, FRAP and DPPH scavenging assays. ZnO NPs showed excellent anti-inflammatory activity with the synthesized ZnO NPs performing better in membrane stabilization. Clinical pathogens were inhibited by ZnO NPs when compared with Cefuroxime, a standard drug. These efficient biological activities could be utilized in several biological applications.

ABSTRACTThe global outbreak of SARS-CoV-2 has spurred a reassessment of Municipal Solid Waste management strategies and approaches. A significant need for sanitation and hygiene was accentuated for disease prevention and control with the onset of the pandemic. With an alteration of the status quo in waste management system, an unprecedented amount of face masks, protective equipment, and other biological wastes was generated in the form of Municipal Solid Waste . This upsurge of potentially infected wastes originated a risk of transmission amongst frontline workers. Furthermore, the potential contamination of Municipal Solid Waste was rendered as a legitimate threat due to improper collection practices, disposal and handling of solid waste. Several novel waste disposal techniques and waste management policies were also introduced during this period. However, the sanitation-policy making-occupational safety nexus remains inadequately explored under the prevalent COVID-19 scenario. Through the prism of shifting waste composition, this review offers a global assessment of existing solid waste management systems during the COVID-19 pandemic. The physiological and psychological hazards faced by the frontline workers were explored and instances of best-case and worst-case policies on solid waste handling were recorded. Modern methods of waste disposal and latest trends of policymaking were evaluated. A model study of unsupervised learning via Partition Around Medoids cluster analysis was undertaken to reveal underlying patterns of waste management policies. Although, the clusters were formed devoid of any socio-economic parameters, this study strives to indicate proof of concept and can serve as a precursor to advanced clustering studies.

ABSTRACTLignosulfonate /silver nanoparticles (L–AgNPs) were synthesized by a one-pot method. The structure of the prepared L–AgNPs was characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The prepared L–AgNPs were spherical with a size of approximately 16–22 nm, whereas the structure of lignosulfonate did not change during the synthesis. The synthetic method is green, simple and fast. As a heavy metal, establishing a green and rapid detection method for mercury ion is very important. L–AgNPs exhibited high selectivity for mercury (II), a detection range of 0–68 µM, and a minimum detection limit of 7 nM. The detection method developed in this work was used for the determination of mercury (II) in actual water samples, and the results agreed well with those obtained by a colorimetric method. This study provides a new idea for the practice of green chemistry and a novel method for the detection of mercury (II).

ABSTRACTDirect C–H bond functionalization is the most effective technique to construct C–X (X = C, N, O, S, etc.), which could simplify the conventional synthesis methods. Transition-metal-catalyzed C–H bond functionalization needs metal catalysts such as palladium, rhodium, iridium, cobalt, copper, etc., which is not conducive to its sustainable development. In recent years, C(sp3)-H bond functionalization without transition metal catalyst has been studied increasingly. In the meantime, electrochemistry has become one of the most dynamic research fields in organic synthesis for the reason that it can substitute the traditional expensive and polluting metal salt oxidants (e.g. Cu2+, Ag+ salt) with current/electrons to act as a redox agent. So the applications of electrochemistry combined with transition-metal-free C(sp3)-H bond functionalization to solve some long-standing challenges have gradually gotten more and more attention in recent years. In this review, the researches on transition-metal-free electrochemical-induced C(sp3)-H bond functionalization from 2016 to now will be systematically presented and the future research hotspots and difficulties in this field will also be prospected.

ABSTRACTThe original synthesis of gamma-(2-bromo-2-methylpropionate)-epsilon-caprolactone (BMPCL), in use since 1999, has an overall yield of 17% and uses a Cr(VI) reagent for a key oxidation. Despite these liabilities, this synthetic procedure has been reported in all subsequent uses of BMPCL. This is due to BMPCL’s desirable capacity as an inimer – the tertiary alpha-bromo ester functionality allows initiation of controlled radical polymerization while the strained lactone moiety can act as a monomer in ring-opening polymerizations. These orthogonal capacities make BMPCL useful for the synthesis of complex polymer architectures such as combs. This paper reports a higher yielding, telescoped BMPCL synthesis that reduces the use of toxic reagents. Utilizing a mild and near-quantitative activated-DMSO mechanism, the Swern oxidation, in place of pyridinium chlorochromate increases the yield by approximately half to 25% (average of three trials) while eliminating heavy metal usage. In an additional effort for synthetic efficiency, the number of chromatographic purifications was reduced from three to one.

ABSTRACTIn this work, an efficient synthesis of 3-hydroxy chromones was accomplished through oxidative cyclization mediated by lipase. This enzymatic process has salient features of environmental friendliness, mild reaction condition, satisfactory yield, green reusable biocatalyst, and short reaction time. The proposed method expands the application of lipase in organic synthesis.

ABSTRACTPolyesters are important materials with a wide range of applications, but there has been increasing concern over their sustainability. One example is the need for safer, bio-derived solvents to replace those currently in use for the polymer’s synthesis and processing. In this work, several variants of the bio-based cellulose/levoglucosenone derived solvent Cyrene, namely the ketal derivatives dioxolane Cygnet, dioxane Cygnet and dioxepane Cygnet were synthesized and tested as media for enzymatic polycondensation reactions using bio-based building blocks. Dioxolane Cygnet and dioxepane Cygnet were found to be suitable solvents for enzymatic polycondensation reactions, with dioxolane Cygnet being the preferred solvent, yielding polymers with a Mn >22 kDa. In addition, these solvents were tested in the biocatalyzed synthesis of levoglucosenone-based polyesters. The alternative solvents gave superior yields to those previously observed, demonstrating the versatility of these solvents in enzymatic polycondensation reactions, representing the first synthetic polymer-solvent system fully derived from cellulose.

ABSTRACTIonic liquids (ILs) have been widely explored as alternative solvents for carbon dioxide (CO2) capture and utilization. However, most of these processes are under pressures significantly higher than atmospheric level, which not only levies additional equipment and operation costs, but also makes the large-scale CO2 capture and conversion less practical. In this study, we rationally designed glycol ether-functionalized imidazolium, phosphonium and ammonium ILs containing acetate (OAc–) or Tf2N– anions, and found these task-specific ILs could solubilize up to 0.55 mol CO2 per mole of IL (or 5.9 wt% CO2) at room temperature and atmospheric pressure. Although acetate anions enabled a better capture of CO2, Tf2N– anions are more compatible with alcohol dehydrogenase (ADH), which is a key enzyme involved in the cascade enzymatic conversion of CO2 to methanol. Our promising results indicate the possibility of CO2 capture under ambient pressure and its enzymatic conversion to valuable commodity.

ABSTRACTAn effective ligand for the Ullmann-type C–N coupling reaction in water has been obtained using a novel tactic, namely, introducing a third group into the ligand to both improve the ligand’s water solubility and enhance the ligand’s coordinating ability. Applying this method, we have developed an effective ligand for the Cu-catalyzed amination of aryl halides, in particular, for aryl chlorides in water. The substrate diversity of the catalyst system, relatively less time required (6–12 h), and water as the reaction solvent make it attractive in both academia and industry.

ABSTRACTNovel mono, di and tetra cationic surfactant (CS) molecules were synthesized by quaternization reaction of diamide with cetyl-2-chloroacetate with different ratio 1:1, 1:2 and 1:4. The chemical structures of the synthetic compounds were proven by FTIR and 1HNMR. The synthetic cationic surfactants were examined as corrosion inhibitors for carbon steel (CSt) in 1.0 M HCl solutions using chemical and electrochemical measurements. Some surface-active properties were determined and linked to the inhibition process. The inhibition efficiency increases with increasing concentration of CS molecules and decreasing temperature. Potentiodynamic polarization technique showed that the three CS molecules are classified as mixed inhibitors. The inhibition process was explained by its spontaneous adsorption on the surface of CSt, according to Langmuir isotherm. The results confirmed that the cationic surfactants successfully inhibited the corrosion of CSt in the investigated corrosion medium and the inhibition efficiency reached 96.08%.

ABSTRACT1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) has received a significant importance in organic synthesis during recent years because of its interesting ability to catalyze organic reaction sufficiently at mild conditions. DBU can work as a catalyst under simple conditions inducing the operational simplicity of the experimental procedures by reducing the side products and waste. The notable advantages in these cases include the less expensive catalyst which is commercially readily available, easy to handle, and most importantly recoverable. The DBU as a catalyst has been explored for several practical methodologies and is highly useful for the synthesis of a wide variety of organic materials. The selectivity (chemo-, regio-, and stereo-) of these reactions is highly impressive and applicable in modern chemical transformations. The DBU possesses enhanced basic properties and high mechanical as well as thermal stability. In recent years, a large number of organic transformations have been carried out using DBU as a catalyst. The DBU has successfully been employed to conduct a wide variety of organic reactions including usual chemical modifications, cyclizations, eliminations, esterifications, condensation reactions, multicomponent reactions, etc. In fact, during last few decades, a tremendous interest has sparked in various organic transformations promoted by DBU and a large number of publications have appeared in the literature. Since chemical transformations catalyzed by DBU have recently been proven to be highly important in organic synthesis we review in this article the recently appeared significant protocols using DBU as a catalyst.

ABSTRACTIn this work, the extract of mango leaf was chosen as a green raw material, and ethylenediamine (EDA) as a supporting material for a controllable one-step reaction to realizing white light. During the reaction, EDA could balance the precursor consumption, and participated in the formation of the carbon dots (CDs). The final integrated emitting color of the materials could be adjusted to white light with a one-step hydrothermal treatment. The composite solution was directly coated on a commercial 365 nm light-emitting diode (LED) chip without a polymer matrix and showed a stable white light with CIE coordinates of (0.326, 0.328). This work developed an interesting method for tuning the reaction process in a complex system and provided a simple way of realizing an integrated white light with a single wavelength excitation.

ABSTRACTA less hazardous and energy efficient reaction performed using freshly squeezed citrus juice as solvent has been designed and implemented within a sophomore level organic chemistry laboratory. The primary learning objectives are to enable students to (i) identify and reflect upon various green chemistry principles such as waste prevention, atom economy, less hazardous synthesis, use of safer chemicals, catalysis, design for energy efficiency, and inherently safer chemistry for accident prevention; (ii) use proton NMR spectroscopic data to characterize a synthesized Schiff base (imine); and (iii) describe the reaction mechanism for imine formation, including the reasoning for why citrus juice is an excellent reaction medium. Specifically, 4-nitrobenzaldehyde is combined with 4-methoxyaniline at room temperature in the presence of four different fruit juices as reaction media to successfully synthesize an imine that is expensive to procure commercially. This is followed by students undertaking reduction of the imine to form a secondary amine which has a dramatically distinct color due to the disruption in conjugation. In performing this overall reductive amination, students expand their knowledge on acid-catalyzed imine synthesis and its mechanism, strengthen their practical skills in the laboratory, and reflect on green chemistry principles within the context of fundamental organic reactivity.

ABSTRACTGlobal reactivity descriptors of isopropyl acetate (IPA) and thermo-kinetic aspects of its oxidation via OH radicals have been studied. Transition state theory (TST) was utilized to estimate the bimolecular rate constants. Ten oxidation pathways have been investigated, and all of them are exothermic. The potential energy diagram has been sketched using different pre- and post-reactive complexes for all reaction pathways. Rate coefficient calculations were obtained directly by connecting the separated reactants with different transition states. The results indicate that the reaction of IPA with OH radicals occurs in the ground state rather than the excited state, and the rate constants obtained directly and from the effective approach are the same, which confirmed the accuracy of the estimated pre-reactive complexes and the reaction mechanism. Rate constants and branching ratios show that hydrogen atom abstraction from the iso C − H (C2 atom) bond is the most kinetically preferable route up to 1000 K, while at higher temperatures, H-atom abstraction from the out-of-plane CH3 group (C3 atom) became the most dominant route with high competition with that of the in-plane CH3 group (C4 atom).