Green Metrics Research Articles

The use of methanol as a C1 building block.

Methanol is a key building block in the chemical industry. In recent years, it has been used as a C1 source in various organic transformations in the presence of a transition-metal catalyst. This protocol describes the ruthenium- and cobalt-catalyzed utilization of methanol in different types of methylation reactions and heterocycle synthesis. Initially, we describe the synthesis of tridentate ligands (L1-L3) and their corresponding Ru(II) complexes (Ru-1, -2 and -3) and then detail how to apply these Ru(II) complexes and Co/PP3 (PP3 = P(CH2CH2PPh2)3) in various methanol dehydrogenative coupling reactions. We discuss six types of transformations by using methanol or a methanol/water mixture. The experimental setup for all the catalytic reactions is similar and involves adding all the respective reagents and solvents to an argon-filled pressure tube, which is sealed (by screw cap) and refluxed at the indicated temperature before the desired products are isolated and characterized. The catalytic systems described in this protocol work well for both small-scale and preparative-scale synthesis of various N-methylated amines/amides, C-methylated products and quinazolinones. These catalytic reactions are greener and more sustainable than conventional synthesis methods, with only H2 and/or H2O as by-products, and we evaluate the 'green chemistry metrics' for a typical substrate. The total time required for the catalytic experiments described in this protocol is 16-28 h, and the operation time is 4 h. An average level of expertise in organic synthesis is required to carry out these protocols.

Multifunctional Deep Eutectic Solvent-Catalyzed Synthesis of Dihydropyrimidinethiones: A Sustainable Approach for Green and Efficient Reactions

Background: This study investigates the synthesis of dihydropyrimidinethiones using a multifunctional deep eutectic solvent (DES) composed of Choline chloride (ChCl) and ammonium thiocyanate. This DES serves as a catalyst, solvent, and reagent, providing a simple, highyielding, and environmentally friendly method for dihydropyrimidinethione synthesis. The use of DES in this capacity offers several advantages, including reduced environmental impact, high efficiency, and ease of use, highlighting its potential as a sustainable alternative in organic synthesis. Objective: The objective of this study is to investigate the application of a deep eutectic solvent (DES) composed of ChCl and ammonium thiocyanate as a catalytic solvent and reagent system for synthesizing dihydropyrimidinethiones. The aim is to simplify the reaction setup, improve yields, and enhance the green metrics of the process. Methods: ChCl and ammonium thiocyanate were combined to form a DES catalyst-solvent system. Dihydropyrimidinethiones were synthesized in one-pot reactions at ambient temperature. Green metrics and DES recovery were evaluated. Comparative analysis with traditional methods was conducted. Results: The DES efficiently catalyzed dihydropyrimidinethione synthesis with high yields. Simplified reaction setup, safe solvent properties, and favorable green metrics. DES was recoverable and reusable, outperforming traditional methods in efficiency and eco-friendliness. Conclusion: The ChCl and ammonium thiocyanate DES demonstrated remarkable efficiency and eco-friendliness in dihydropyrimidinethione synthesis. The toxicity-free, multifunctional roles of the DES, serving as a catalyst, solvent, and reagent, highlight its novelty and potential as a sustainable alternative in organic chemistry. This study simplifies the synthesis process and improves yields and green metrics, showcasing the DES as a promising candidate for future research and industrial applications.

Visible Light Mediated Synthesis of 3‐Indolmethyl Chromones via the Cyclization of o‐Hydroxyaryl Enaminones with 3‐Indoleacetic Acids Catalyzed by Graphitic Carbon Nitride Adorned with Copper Nanoparticles

AbstractCopper nanoparticles (Cu2O NPs) supported on graphitic carbon nitride (g‐C3N4) have been introduced as an effective heterogenous catalyst for the synthesis of 3‐indolmethyl chromones (3 a–q) under visible light conditions via the cyclization of o‐hydroxyaryl enaminones with 3‐indoleacetic acids. The catalyst was thoroughly characterized using various techniques such as FT‐IR, PXRD, XPS, FE‐SEM, EDX, TEM, and HR‐TEM analysis. The optimized reaction conditions enabled the high yield production of a wide range of 3‐indolmethyl chromones in a short timespan at room temperature under visible light and method was successfully applied to the gram‐scale synthesis. Importantly, the catalyst could be reused for up to five cycles without significant decrease in its activity. This approach aligns with eco‐friendly principles, demonstrating favorable green chemistry metrics for compound 3 a, including process mass intensity (7.83), environmental impact factor (6.83), atom economy (67.56 %), reaction mass efficiency (60.76 %), chemical yield (92.37 %), mass intensity (1.64), mass productivity (60.97 %), carbon efficiency (69.15 %) and optimum efficiency (89.93 %).

AuNP/MIL-88B-NH2 Nanocomposite for the Valorization of Nitroarene by Green Catalytic Hydrogenation.

The efficiency of a catalytic process is assessed based on conversion, yield, and time effectiveness. However, these parameters are insufficient for evaluating environmentally sustainable research. As the world is urged to shift towards green catalysis, additional factors such as reaction media, raw material availability, sustainability, waste minimization and catalyst biosafety, need to be considered to accurately determine the efficacy and sustainability of the process. By combining the high porosity and versatility of metal organic frameworks (MOFs) and the activity of gold nanoparticles (AuNPs), efficient, cyclable and biosafe composite catalysts can be achieved. Thus, a composite based on AuNPs and the nanometric flexible porous iron(III) aminoterephthalate MIL-88B-NH2 was successfully synthesized and fully characterized. This nanocomposite was tested as catalyst in the reduction of nitroarenes, which were identified as anthropogenic water pollutants, reaching cyclable high conversion rates at short times for different nitroarenes. Both synthesis and catalytic reactions were performed using green conditions, and even further tested in a time-optimizing one-pot synthesis and catalysis experiment. The sustainability and environmental impact of the catalytic conditions were assessed by green metrics. Thus, this study provides an easily implementable synthesis, and efficient catalysis, while minimizing the environmental and health impact of the process.

Adsorption separation of oxytetracycline hydrochloride using natural and nanostructured clay mineral of silica in synthetic solution: Integration to white and green chemistry metrics

As emerging water pollutants, oxytetracycline (OTC) and its derivatives are detrimental to humans, organisms, and aquatic ecosystems. Oxytetracycline hydrochloride (OTCH) was effectively absorbed from water by silica (SiO2) and metakaolinite (MK). In this study, we employed a unique metric known as BAGI to evaluate the suggested analytical method's suitability effectively. Blue applicability grade index (BAGI) complements green assessment tools such as the Green analytical procedure index (GAPI), Complex green analytical procedure index ComplexGAPI, Analytical GREEnness (AGREE), Analytical greenness for sample preparation (AGREEprep), and Analytical eco-scale (ESA). The BAGI metric focuses on the practical aspects of white analytical chemistry, especially those related to “blue.” The optimal parameters for adsorbing OTCH were determined by a study (pH, OTCH concentration at the beginning of the reaction, sorbent dose, and reaction duration). This study of sorbent properties was conducted via X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The highest levels of OTCH adsorption were seen at pH 5–6 for MK and at pH 7 for SiO2. The most desirable clay minerals are those with smaller quantities. The Langmuir model accurately characterizes the results, showing a strong correlation between OTCH sorption onto MK with a maximum capacity of 165.04 mg/g and a moderate correlation for SiO2 with a maximum capacity of 25.3 mg/g. Therefore, these findings regarding the effectiveness of adsorption and the analysis of properties offer supplementary insights into the potential use of clay minerals as cost-effective and eco-friendly sorbents for treating wastewater.

How to Measure the Greenness of Chemicals? A Case Study on Butadiene Production Applying Green Metrics and Life Cycle Assessment

AbstractThe greenness of naphtha‐ and bioethanol‐based butadiene was compared using green metrics (GM) and life cycle assessment (LCA). GM provide predominantly qualitative results, showing advantages for bioethanol‐based butadiene. LCA indicates benefits of bioethanol‐based butadiene in terms of global warming and fossil resource consumption, but drawbacks in acidification, eutrophication, radiation, land use, ozone depletion, particulate matter, ozone formation, metal depletion, and freshwater consumption. When comparing both assessment approaches used, LCA offers a more comprehensive environmental assessment while GM is limited to a smaller section of the value chain but address additional aspects such as safety of chemicals.

Solvent-free conversion of CO2 in carbonates through a sustainable macroporous catalyst

The novelty of this work consists of synthesizing and exploiting a heterogeneous catalyst containing ammonium chloride as part of the polymeric sponge sites for CO2 capture. To this aim, the polymerization of 2-acryloyl(oxyethyl)trimethylammonium chloride was performed in cryo-condition, in the presence of a crosslinking agent, obtaining a lightweight macroporous freestanding material. Its efficiency in converting aromatic and aliphatic epoxides to the corresponding carbonates was successfully proved by using proton Nuclear Magnetic Resonance (1H NMR). Remarkably, the conversion of styrene oxide (SO) to styrene carbonate (SC) reached a yield of 99 % after 24 h of reaction. The calculated yield versus the aliphatic cyclohexene oxide is 71 %. Similar results were obtained by substituting the resin counter anion with Br−, although the conversion kinetic was slower than the chloride. It is worth noticing that reactions took place in the mixture without adding the tetrabutylammonium bromide (TBAB), typically used as a co-catalyst to convert epoxides into carbonates. The recyclability of the as-prepared catalyst was evaluated for four reaction cycles, evidencing stable properties without significant depletion of CO2 capture efficiency. Most importantly, the post-cleaning of the catalytic sponge is not required to be reused. Finally, the green chemistry metrics applied to the process demonstrated that our approach significantly mitigates risks and reduces environmental impact, thus elevating the overall cleanliness of our proof of concept.

Smart green versatile spectrophotometric and HPTLC techniques for the investigation of ambroxol, doxycycline, in presence of ambroxol precursor and impurity: Appraisal and comparison with various green metrics

Recently, Countless people have become affected as a result of the Covid-19 crisis. Even after recovery, COVID-19 can lead to respiratory difficulties and lung impairment consequently; bacterial infections have a good possibility of infiltrating our respiratory system due to reduction in respiratory immunity. Therefore, the importance of the chosen mixture of doxycycline and ambroxol becomes clear here curing bacterial illnesses invade respiratory tract. The ternary blend of (DOX) doxycycline hyclate, (AMB) ambroxol hydrochloride, (IMP) chemical ambroxol precursor, and pharmacopeial impurity was quantified using four contemporary, selective, and straightforward methods. Method (I) was area under the curve spectrophotometric method (AUC), where zero order absorption spectra were used for calculating the area under the curve of AMB, IMP, and DOX in ranges of 205–219, 222–245, and 264–290 nm, respectively. Each component's absorptivity values (a) at the chosen area were computed. Method (II) was differential dual wavelength (DDW), where upon collecting the first derivative spectra of AMB, IMP, and DOX, amplitudes at 252–263.4, 236–246.6, and 388.8–420 nm were subtracted, consecutively. Method (III) the mean centering of ratio spectra spectrophotometric method (MCR), peak to peak amplitudes on these resulted spectra were measured at (258.2 and 258.4 nm) for AMB, (264.4 and 264.6 nm) for IMP, and at (230.4 and 230.6 nm) for DOX. In addition, method (IV) HPTLC using a stationary phase made of silica gel HPTLC plates that had been pre-treated with 0.27 M di-sodium-EDTA (pH 9 with 21 % sodium hydroxide). The platform is developed using the eluent of ethyl acetate, acetone, distilled water, and acetic acid (9:2:0.7:0.55, by volume) and scanning by employing ultraviolet light regarding AMB and IMP at 254 nm while DOX at 380 nm. For validating the developed procedures, ICH principles were adhered to. The proposed methods were successful in studying dosage form containing investigated substances. The developed techniques' greenness features were assessed using a variety of greenness parameters, and an environmental evaluation comparison between the current methods and the reported one was done. Obtained methods' statistical analyses were also performed.

Assessment of Chemical Products and Processes: Green Metrics and Life Cycle Assessment – A Comparison

AbstractGreen chemistry aims to use renewable materials, reduce waste, and avoid toxic substances and is defined by 12 principles of green chemistry. Green metrics (GM) are measurable figures that assess adherence to the 12 principles of green chemistry. GM are designed to be user‐friendly and can be applied without detailed process knowledge. Life cycle assessment (LCA) is another approach used to estimate the environmental impacts of products or processes throughout their life cycle. This paper compares LCA and GM, exploring their suitability for assessing the greenness of chemical products and processes. This includes the discussion of strengths and weaknesses, limitations, application areas, benefits of combining both approaches, and how to handle conflicting results.

Multi-criteria decision analysis: technique for order of preference by similarity to ideal solution for selecting greener analytical method in the determination of mifepristone in environmental water samples

This work proposes the use of multi-criteria decision analysis (MCDA) to select a more environmentally friendly analytical procedure. TOPSIS, which stands for Technique for Order of Preference by Similarity to Ideal Solution, is an example of a MCDA method that may be used to rank or select best alternative based on various criteria. Thirteen analytical procedures were used in this study as TOPSIS input choices for mifepristone determination in water samples. The input data, which consisted of these choices, was described using assessment criteria based on 12 principles of green analytical chemistry (GAC). Based on the objective mean weighting (MW), the weights for each criterion were assigned equally. The most preferred analytical method according to the ranking was solid phase extraction with micellar electrokinetic chromatography (SPE-MEKC), while solid phase extraction combined with ultra-high performance liquid chromatography tandem mass spectrometry (SPE-UHPLC-MS/MS) was ranked last. TOPSIS ranking results were also compared to the green metrics NEMI, Eco-Scale, GAPI, AGREE, and AGREEprep that were used to assess the greenness of thirteen analytical methods for mifepristone determination. The results demonstrated that only the AGREE metric tool correlated with TOPSIS; however, there was no correlation with other metric tools. The analysis results suggest that TOPSIS is a very useful tool for ranking or selecting the analytical procedure in terms of its greenness and that it can be easily integrated with other green metrics tools for method greenness assessment.

Tailoring the Formation of Functionalized Furans from Glucose in Water with Nature-Sourced Catalysts and In Situ NMR.

Chain elongation of unprotected carbohydrates in water under mild conditions remains a challenge both in chemical and biochemical synthesis. The Knoevenagel addition or condensation enables transformations to bioactive scaffolds for pharmaceutical and agrochemical compounds. Unfortunately, the catalysts in use for these transformations often reduce the green metrics of the transformations. Here, we use in situ NMR visualizations to explore the prospective use of natural catalysts for the synthesis of triple- and quadruple-functionalized furan- or dihydrofuran-derivatives from glucose and malononitrile. The dihydrofuran derivatives are formed as kinetic, major intermediates in the pathway to furan derivatives when using naturally abundant MgO or bio-sourced chitosan and N-Methyl-d-glucamine (meglumine) as the catalysts in water. Both catalyst loading, solvent composition and pH can be adapted to populate dihydrofurans with four substituents by slowing down their further reactions. Higher temperatures and higher pH values favor the formation of triple-functionalized furans over quadruple-substituted dihydrofurans, which may be bicyclic or monocyclic. Compared to more traditional catalysts, nature-sourced options offer more sustainable options that emulate natural processes. Visualization with in situ NMR contributes to streamlining the development of cheap and environmentally benign procedures for carbohydrate chain elongation.

A highly sensitive micelle-sensitized spectrofluorimetric approach for analysis of montelukast in dosage forms and human plasma: Greenness assessment and application to content uniformity testing

In this work, a highly sensitive, rapid, affordable, and green micellar-enhanced spectrofluorimetric method was developed for the estimation of montelukast in its tablets and human plasma for the first time. After excitation at 224 nm, a micellar solution of cetrimide containing montelukast produced high native fluorescence emission at 404 nm. A 3-fold enhancement of the drug's fluorescence intensity and quantum yield, as well as the method's sensitivity, was produced using cetrimide as a micellar system. The experimental parameters influencing the spectrofluorimetric behavior of the studied drug were carefully investigated. The quantum yield of montelukast was also computed and found to be as high as 20 %. A straight-lined calibration plot was obtained over the concentration range of 50.0–1000.0 ng/mL. The proposed method showed high sensitivity down to the nanogram level with quantitation and detection limits of 34.68 and 11.45 ng/mL, respectively. The method was successfully applied for the analysis of the studied drug in its tablets with high % recoveries and low %RSD values. As the proposed fluorimetric method is highly sensitive and selective towards montelukast, it could successfully test the content uniformity of its tablets following the guidelines of the British Pharmacopoeia. Montelukast was also successfully determined in spiked human plasma samples due to the increased sensitivity of the method. The greenness profile and ecofriendliness of the proposed method were verified using two different green metrics, including AGREE and GAPI, which demonstrated the excellent greenness of the method. The developed method was validated according to ICH Q2 (R1) guidelines.

1-(3,4-Dimethoxyphenyl)-3-(4-methoxyphenyl)-3-(1H-1,2,4-triazol-1-yl)propan-1-one

The study of new catalytic protocols for the synthesis of organic compounds with a more sustainable perspective is of interest. The use of ionic organic solids, such as 1,3-bis(carboxymethyl)imidazolium chloride as a catalyst has allowed the Michael addition of N-heterocycles to chalcones. This methodology has been applied to the unique preparation of the potential bioactive compound 1-(3,4-dimethoxyphenyl)-3-(4-methoxyphenyl)-3-(1H-1,2,4-triazol-1-yl)propan-1-one with moderate yield, due to the retro-Michael reaction. Both synthetic reactions (i.e., preparation of chalcone and triazole Michael-addition to chalcone) have good green metrics.

Voltammetric analysis of pholcodine on graphene-modified GNPs/PTs with green assessment

Pholcodine, an anti-tussive medication widely used as an over-the-counter, OTC drug, has recently faced restrictions in several countries. This paper presents a sensitive electrochemical approach for pholcodine detection. The electrochemical method involved fabricating a graphene nanoplatelets electrode, incorporating polythiophene nanospheres polymer to promote electron transfer and increase the activated surface area. Characterization of the fabricated electrode was performed using transmission electron microscopy, ATR-Fourier-transform infrared spectroscopy, X-ray crystallography, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. The electrochemical behavior of pholcodine with the fabricated electrode was investigated using cyclic voltammetry, chronoamperometry, square wave voltammetry (SWV), and differential pulse voltammetry (DPV). The developed electrode led to a linear response for pholcodine ranging from 10 to 45 mg/L with detection limits of 1.41 and 1.51 mg/mL for SWV and DPV, respectively and quantification limits of 4.27 and 4.57 mg/L for SWV and DPV, respectively. The proposed method has accurately recovered pholcodine in spiked serum samples with a recovery percentage ranging from 1.2 to 2.9%. The optimized method is found to be accurate, precise, and robust by applying validation parameters provided by International Council for Harmonization. Two green metrics were computed to assess the method’s greenness, the findings showed that the developed method is environmentally friendly with minimum sample preparation steps.

Zinc-aluminum mixed oxide nanocomposites catalyzed KA2 coupling of ketone, amine, and an alkyne: An environmentally benign approach

Heterogeneous catalysis is of prime importance especially to produce essential fine chemicals and organic molecules. Herein, we presented the simplest synthesis and application of zinc-aluminum mixed oxide nanocomposites (ZnAl-MO NCs) as an efficient catalyst for three component one-pot KA2 coupling reactions to prepare tetrasubstituted propargylamines. The as synthesized ZnAl-MO NCs were well characterized using spectroscopic tools viz. PXRD, BET, XPS, HRTEM, ICP techniques. ZnAl-MO NCs selectively catalyze the KA2 coupling reactions between ketone, amine and an alkyne affording wide range of functional substrates with higher conversion rates and yield. The sustainability of the catalyst was also studied systematically by evaluating the green chemistry metrics such as E factor, atom economy and turn over numbers. Notably, the architectures proposed methodology not only highlights the versatility of environmentally benign novel catalyst but also displays lower leaching levels for zinc and aluminum respectively.

Sustainable Beckmann Rearrangement using Bead-Milling Technology: The Route to Paracetamol.

To address the growing demand for more sustainable and greener chemistry, mechanochemical methodologies are emerging as key players. However, to date there has been little data highlighting the benefits of these rising mechanochemical technologies with regard to process scale-up activities or implementation in commercial production scale. Herein, we report the first application of bead-mill technology (Dyno®-mill) for the sustainable mechanochemical synthesis of Acetaminophen, known under the brand name Paracetamol. Using the Beckmann rearrangement, the optimized solvent-free methodology delivered a final product on a scale of several tens of grams. In comparison to current production solvent-based process, the proposed process achieves a higher yield while also allowing the removal of solvents in the chemical reaction, hereby reducing one of the extensive drivers to waste generation. The mechanochemical approach was compared to solvent-based process using a combination of green metrics and EcoScale score. The mechanochemical synthesis of paracetamol scores the highest for all the metrics over currently used solution-based processes.

Efficient and sustainable tandem annulation-decarboxylation reaction using ecocatalysis

Substituted cyclohexenones are well-known building blocks for the synthesis of numerous natural products and bioactive compounds. Despite their widespread use, they are prepared under conditions that are not compatible with the principles of green chemistry. Here the synthesis of substituted cyclohexenones was revisited using a tandem annulation-decarboxylation strategy, in an eco-friendly process without compromising on efficiency. To meet this challenge, environmental catalysts, named ecocatalysts®, which derived from biomass wastes were used. Under microwave activation, ecocatalysis assisted by statistical tools led to excellent yields, as well as remarkable green metrics for the whole synthetic process, which both exceeded those previously reported. The reaction was scaled-up allowing the recycling assessment of the best ecocatalysts®. The reaction was also extended to other substrates. The catalytically active species within the best ecocatalyst® was identified through extensive characterisation by MP-AES, XRPD, SEM, XPS and solid-state NMR, allowing to depict a mechanism confirmed by DFT calculations.

Urban green inequality and its mismatches with human demand across neighborhoods in New York, Amsterdam, and Beijing

ContextUrban green spaces (UGS) are not evenly distributed within cities, and some neighborhoods with high socio-environmental demands require more UGS than others. This raises two challenges: green inequality and demand-based inequity. However, comprehensive assessments of UGS inequality and inequity in cities worldwide are lacking.ObjectivesWe aim to develop a multi-level approach and supply-demand concept to assess UGS inequality and inequity across neighborhoods in international cities with contrasting geographical and socio-political contexts.MethodsWe measured multi-level green accessibility and human demands based on Earth Observation and statistical data. UGS inequality and supply-demand mismatches were assessed by Gini coefficients, spatial cluster analysis, and statistical models.ResultsWe found that: (1) UGS inequality is primarily reflected by the public park per capita in three cities. New York has larger UGS inequality than Beijing and Amsterdam. (2) Demand-based inequity in terms of low supply and high demand is mainly scattered around the city center in three cities. Tree coverage does not align with environmental pressures (LST/PM2.5) in New York and Beijing. (3) Relations between green supplies and human demands vary by cities and indicators. A shorter distance to the nearest large park is associated with a higher proportion of the elderly and children in New York and Amsterdam.ConclusionsOur findings can inform UGS allocations to improve landscape sustainability in the neighborhoods with low green supply and high human demand, and to prioritize specific green metrics based on demand-oriented equity.

The greener the living environment, the better the health? Examining the effects of multiple green exposure metrics on physical activity and health among young students

The sedentary and less active lifestyle of modern college students has a significant impact on the physical and mental well-being of the college community. Campus Green Spaces (GSs) are crucial in promoting physical activity and improving students' health. However, previous research has focused on evaluating campuses as a whole, without considering the diverse spatial scenarios within the campus environment. Accordingly, this study focused on the young people’s residential scenario in university and constructed a framework including a comprehensive set of objective and subjective GSs exposure metrics. A systematic, objective exposure assessment framework ranging from 2D (GSs areas), and 2.5D (GSs visibility) to 3D (GSs volume) was innovatively developed using spatial analysis, deep learning technology, and unmanned aerial vehicle (UAV) measurement technology. Subjective exposure metrics incorporated GSs visiting frequency, GSs visiting duration, and GSs perceived quality. Our cross-sectional study was based on 820 university students in Nanjing, China. Subjective measures of GSs exposure, physical activity, and health status were obtained through self-reported questionnaires. The Generalized Linear Model (GLM) was used to evaluate the associations between GSs exposure, physical activity, and perceived health. Physical activity and social cohesion were considered as mediators, and path analysis based on Structural Equation Modeling (SEM) was used to disentangle the mechanisms linking GSs exposure to the health status of college students. We found that (1) 2D indicator suggested significant associations with health in the 100m buffer, and the potential underlying mechanisms were: GSs area → Physical activity → Social cohesion → Physical health → Mental health; GSs area → Physical activity → Social cohesion → Mental health. (2) Subjective GSs exposure indicators were more relevant in illustrating exposure-response relationships than objective ones. This study can clarify the complex nexus and mechanisms between campus GSs, physical activity, and health, and provide a practical reference for health-oriented campus GSs planning.

Synthesis, characterization, and investigation the catalytic potential of diammonium phosphate modified with bismuth for the one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones through a three-component reaction: An in-depth evaluation using green metrics

A straightforward synthesis of a novel catalyst, bismuth phosphate (Bi(NO3)3/DAP), was achieved using a co-precipitation method. The resulting material underwent thorough characterization employing various techniques, including X-ray diffraction, FTIR, scanning electron microscopy (SEM), and EDX. We investigated the application of Bi(NO3)3/DAP as a catalyst in the 3,4-dihydropyrimidin-2(1H)-ones reaction between urea, ethyl acetoacetate, and various aldehydes. The results demonstrated that the catalyst exhibited excellent catalytic performance, leading to the production of products with impressive yields (89–97 %) in just 15 min in an ethanol medium. Additionally, the heterogeneity of the reaction was confirmed through a hot filtration test. Notably, this catalyst presents notable benefits, such as its easy recovery and ability to be reused for a minimum of five successive cycles, a simple work-up procedure, and the attainment of high product yields. A sustainability evaluation based on green metrics using the E-factor, atom economy (AE), reaction mass efficiency (RME), and optimum efficiency (OE) revealed that the use of a catalyst in the Biginelli reaction enhances environmental sustainability.