Product Yield Research Articles

Petri net modeling and analysis of an IoT‐enabled system for real‐time monitoring of eggplants

AbstractAs the current agricultural industry is facing several challenges such as climate changes and lack of qualified farmers, it is extremely necessary to ensure sustainable agriculture and food supply by smart farming (SF). The SF can assist farmers and the associated stakeholders in making correct decisions on improving the yield and quality of agricultural products. In this study, an SF system based on low‐cost Raspberry Pi and Internet of Things (IoT) technologies has been successfully implemented. Through the data items detected by sensors to deeply manage the planting process, the IoT‐enabled communication protocol under ISO standards of Message Queuing Telemetry Transport (MQTT) was used. The bar charts of real‐time environmental parameters are presented on ThingsBoard to achieve the goal of data visualization. Meanwhile, a web server is built for the customized requirements, and the historical datasets are stored in the SQLite database system. Furthermore, a Petri net (PN) model was employed to detect all possible abnormal processes and to verify the feasibility and soundness of an IoT‐enabled system by using a software tool, WoPeD. Finally, the experimental results show that the plants cultivated by the proposed IoT‐enabled system are superior to those cultivated by the existing systems in many perspectives, including the monitoring distance, power consumption, precision, deadlock detection, and running time.

CaFe2O4@SiO2-Cu as a novel and highly efficient nanocatalyst for direct conversion of epoxides to β-acetoxy esters

Direct conversion of structurally various epoxides to the related β-acetoxy esters was investigated using catalytic amounts of CaFe2O4@SiO2-Cu. The reactions were accomplished in the presence of acetic anhydride under solvent-free conditions within 0.5–2 h to give desired products in high yields. Initially, the CaFe2O4 nanoparticles were manufactured through a chemical coprecipitation reaction of calcium nitrate and hydrated iron (III) nitrate in the presence of ammonium hydroxide solution, and then calcined at 800 ºC. Next, to protect the prepared CaFe2O4 from oxidation and aggregation, its surface was covered with a silica layer to give CaFe2O4@SiO2. Eventually, by adding copper chloride solution followed by potassium borohydride solid powder, Cu nanoparticles were successfully immobilized on the silica surface and the new CaFe2O4@SiO2-Cu nanocomposite was obtained. FT-IR, SEM, EDX, VSM, ICP-OES, TGA, TEM and XRD techniques were employed to characterize the newly synthesized nanostructure. In addition, durability of the catalyst was considered for several sequential reaction cycles without the notable loss of catalytic activity. The absence of hazardous organic solvents, high product yields, short reaction times and recoverability of the magnetic catalyst are among the remarkable advantages of the introduced procedure.

Biochar application improves maize yield on the Loess Plateau of China by changing soil pore structure and enhancing root growth

Biochar application emerges as a valuable soil management strategy for enhancing crop yield; however, the mechanisms underlying the relationships between soil and plants remain unclear after biochar application. In this study, soil pore characteristics and maize yield were assessed in a five-year biochar-application experiment on the Loess Plateau of China, including four treatments: Control (no biochar), low-dose biochar application (LB, 3 t ha−1), moderate-dose biochar application (MB, 6 t ha−1), and high-dose biochar application (HB, 9 t ha−1). Root growth traits were evaluated by cultivating maize in intact soil cores collected from field conditions using X-ray computed tomography. Our findings indicate that, compared to the Control, the HB treatment enhanced macroporosity (> 0.1 mm in diameter), porosity of 0.1–0.5 mm pores, and saturated water content, while reducing macropore connectivity and penetration resistance. However, biochar application treatments did not alter the water retention characteristics from field capacity to permanent wilting point or the plant-available water content (PAWC). Furthermore, the mean angle of primary and seminal roots as well as the length and surface area of entire roots increased in the HB treatment, showing a positive correlation with the porosity of 0.1–0.5 mm pores. The mean diameter of primary and seminal roots, leaf fresh and dry weights, and maize yield also increased in the HB treatment compared to the Control. Partial least squares path modeling analysis indicated that biochar application rates positively impacted on root growth and plant productivity through an indirect influence of soil pore size distribution, with 0.1–0.5 mm pores being particularly crucial for facilitating deeper root penetration and root elongation. These findings demonstrate that biochar application primarily augmented 0.1–0.5 mm pores, rather than affecting smaller pores capable of retaining plant-available water or larger macropores, enhancing deeper rooting and root elongation, thus improving plant productivity and crop yield.

Comparative analysis of RNN versus IIR digital filtering to optimize resilience to dynamic perturbations in pH sensing for vertical farming

AbstractVertical farming (VF) refers to systems of agriculture where crops are grown in trays stacked vertically by exposing them to artificial light and using sensing technology to improve product quality and yield. In this work, we propose an advanced filtering scheme based on recurrent neural networks (RNNs) and deep learning to enable efficient control strategies for VF applications. We demonstrate that the best RNN model incorporates five neuron layers, with the first and second containing 90 long short‐term memory neurons. The third layer implements one gated recurrent units neuron. The fourth segment incorporates one RNN network, while the output layer is designed by using a single neuron exhibiting a rectified linear activation function. By utilizing this RNN digital filter, we introduce two variations: (1) a scaled RNN model to tune the filter to the signal of interest, and (2) a moving average filter to eliminate harmonic oscillations of the output waveforms. The RNN models are contrasted with conventional digital Butterworth, Chebyshev I, Chebyshev II, and elliptic infinite impulse response (IIR) configurations. The RNN digital filtering schemes avoid introducing unwanted oscillations, which makes them more suitable for VF than their IIR counterparts. Finally, by utilizing the advanced features of scaling of the RNN model, we demonstrate that the RNN digital filter can be pH selective, as opposed to conventional IIR filters.

Supply-demand security assessment of water-energy-food systems: A perspective on intra-city coupling and inter-city linkages of ecosystem services

Ensuring the supply-demand security of water-energy-food systems (WEF) is paramount in sustainable cities. Leveraging ecosystem services (ESs) as a bridge between WEF supply and demand, this study proposes a conceptual framework for assessing the supply-demand security of WEF from the perspective of intra-city coupling and inter-city linkages of WEF-related ESs. Considering 14 Liaoning cities, we developed supply-demand indices for three ESs: water yield, carbon storage, and food production. The supply-demand security pattern of WEF was evaluated using Spearman's rank correlation, the Copula model, the coupling coordination degree model, the gravity model, and social network analysis, using these indices. The results show that the supply-demand security of WEF was higher in eastern Liaoning cities and weakened westward. Dandong had the highest supply-demand security, with a 98% probability of achieving moderate surplus in WEF resources. The regions of Dandong-Liaoyang-Anshan-Yingkou-Panjin-Jinzhou and Tieling-Fushun-Benxi formed two extreme WEF coupling coordination gravity networks. Liaoyang, Panjin, and Fuxin emerged as hubs in the WEF coupling coordination gravity networks and exhibited the highest degree and betweenness centrality values. Additionally, Fushun, Liaoyang, Dandong, and Tieling were identified as WEF high coupling coordination nodes. This supply-demand security assessment framework for WEF offers a scientific basis for developing sustainable city strategies.

Depolymerization of Lignosulfonate Catalyzed by Different Solid Base Oxides to Prepare Phenolic Compounds

Lignin is the most abundant aromatic renewable polymer in nature. However, its very stable structure limits its widespread application. To achieve high-value utilization of lignin, this study used solid base oxides to depolymerize calcium lignosulfonate (CLS) for the synthesis of phenolic compounds. The catalyst precursors were prepared by hydrothermal synthesis, and the corresponding mesoporous metal oxides NiO, MgCoOx, and NiMgCoOx were obtained after calcination. MgCoOx and NiMgCoOx had similar but stronger basicity compared to NiO. While all oxides promoted the depolymerization of CLS, NiMgCoOx was identified as the best catalyst, achieving a maximum liquid product yield of 74.3 wt.% and a selectivity of phenolic compounds of 74.52% in the liquid product. In addition, NiMgCoOx showed satisfactory structural and catalytic stability. The experimental results indicated that solid base oxides can capture the active hydrogen in CLS, causing the hydrolysis reaction of ether bonds, and the resulting products continuously depolymerize or polymerize; Co present in the catalyst promotes the adsorption of hydrogen by Ni, while NiO in NiMgCoOx facilitates the adsorption of both reactants and hydrogen. The combination of Ni and Co improves hydrogenation performance.

Catalytic steam reforming of waste tire pyrolysis volatiles using a tire char catalyst for high yield hydrogen-rich syngas

The production of hydrogen and syngas (H2/CO) from waste tires by pyrolysis catalytic steam reforming was investigated in a two-stage fixed bed reactor. In this study, tire char served as a sacrificial catalyst, facilitating the combination of catalytic steam reforming and char steam gasification reactions. The tire char acted as both a catalyst and a gasification reactant, enhancing the gas product yield. The process parameters investigated were, a reforming temperature range of 700–1000 °C, steam space velocity between 2 and 12 g h−1 g−1char and reaction times of 0.5–2 h. The influence of the parameters on the yield and composition of the product gases and the characteristics of the used catalyst were analyzed in detail. The results indicated that higher temperature and steam space velocity increased H2 and CO yields in the presence of a tire char catalyst. Elemental analysis of the used tire char, surface morphology and pore structure provided insights into the extent of tire char consumption in the reaction. Prolonged reaction time allowed for more thorough reactions between the pyrolysis volatiles and tire char, promoting the production of H2. At a reaction time of 2 h, the H2 yield reached 223 mmol g−1, representing 74 wt% of the maximum hydrogen yield.

Potential of California Variety Papaya Leaf Extract (Carica papaya L. California variety) As Bioherbicide of Snake Grass Weed (Cyperus rotundus L.)

Efforts to increase production yields are by controlling weeds. Weeds that often grow and we encounter in cultivated plants are weed grass (C. rotundus). California papaya leaves have the potential to be a bioherbicide because they contain allelochemicals that can inhibit weed growth. This study aims to determine the effect of papaya leaves (C. papaya) on the growth of teki grass (C. rotundus) and determinetheconcentration level of papaya leaf allelopathy that most effectively inhibits the growth of teki grass.The method used was a completely randomized design (CRD) with five replications and four treatmentsof0%, 30%, 50%, and 70%. For data analysis in this study using the SPSS version 25.0 program. Papaya leaf extract (C. papaya) is able to inhibit the growth of weed grass (C. rotundus). The concentration of papaya leaf extract (C. papaya) that most effectively inhibits the growth of weed is 50% concentration with a mortality rate (64%), for the lowest plant heightis50% concentration which is 13.84 cm, for the slowestgrowthrate is 50% concentrationwith a growthrate of -0.16 cm.

Development of fin-LEDs for next-generation inorganic displays using face-selective dielectrophoretic assembly

Micro-light-emitting diodes offer vibrant colors and energy-efficient performance, holding promise for next-generation inorganic displays. However, their widespread adoption requires the development of cost-effective chips and low-defect pixelation processes. Addressing these challenges, nanorod-light-emitting diodes utilize inkjet and dielectrophoretic assembly techniques. Nevertheless, the small volume and edge-directed emission of nanorod-light-emitting diodes necessitate brightness and light extraction improvements. As an alternative, we propose dielectrophoretic-friendly fin-light-emitting diodes, designed to enhance brightness and light extraction efficiency through face-selective dielectrophoretic assembly technology. Our results confirm the potential for next-generation inorganic displays, with a wafer utilization ratio exceeding 90%, a vertical assembly ratio of 91.3%, and a pixel production yield of 99.93%. Moreover, blue fin-light-emitting diodes achieve an external quantum efficiency of 9.1% and a brightness of 8640 cd m−2 at 5.0 V, which, even at this early stage, are comparable to existing technologies.

Exploring the Acetobacteraceae family isolated from kombucha SCOBYs worldwide and comparing yield and characteristics of biocellulose under various fermentation conditions

Bacterial cellulose (BC) is a cellulosic biopolymer produced by specific acetic acid bacteria during kombucha fermentation. In this study, bacterial cellulose-producing strains were isolated from four different global kombucha SCOBY samples obtained from markets in the Netherlands, America, China, and Iran. The strains were identified using biochemical and molecular techniques. The ability of species to produce BC was evaluated under both static and stirred fermentation conditions. Seven dominant strains from the Acetobacteraceae family and the genus of Komagataeibacter and Gluconacetobacter were identified and submitted to NCBI gene bank archives: K. xylinus CH1, K. sucrofermentans IR2, K. intermedius IR3, K. cocois AM2, K. sucrofermentans NE4, K. cocois NE6, and G. liquefaciens NE7. Among these, K. intermedius IR3, isolated from local Iranian SCOBY, exhibited the highest BC production yield at 5.733 ± 0.170 gL−1 under static fermentation conditions. On the other hand, K. xylinus CH1, from Chinese SCOBY, had the highest yield under stirred conditions, producing 12.689 ± 0.808 gL−1 of BC. The BC production yield of both K. xylinus CH1 and K. intermedius IR3 under stirred conditions was 3 and 1.3 times more than static conditions, respectively. Despite the yield differences, static fermentation demonstrated superior physicochemical characteristics; such as moisture content, water holding capacity, and crystallinity degree, compared to stirred. Therefore, depending on the intended application in industry and specific criteria, both products could serve as functional substitutes in food and medicine sectors.

Process Simulation and Technical Evaluation Using Water-Energy-Product (WEP) Analysis of an Extractive-Based Biorefinery of Creole-Antillean Avocado Produced in the Montes De María

The annual increase in the world’s population significantly contributes to recent climate change and variability. Therefore, researchers, engineers, and professionals in all fields must integrate sustainability criteria into their decision-making. These criteria aim to minimize the environmental, social, economic, and energy impacts of human activities and industrial processes, helping mitigate climate change. This research focuses on developing scalable technology for the comprehensive use of avocados, adhering to sustainability principles. This work presents the modeling, simulation, and the WEP (Water-Energy-Product) technical evaluation of the process for obtaining bio-oil, chlorophyll, and biopesticide from the Creole-Antillean avocado. For this, the extractive-based biorefinery data related to water, energy, and products are taken from the material balance based on experimental results and process simulation. Then, eight process parameters are calculated, and eleven technical indicators are determined. Later, the extreme technical limitations for every indicator are demarcated, and an evaluation of the performance of the indicators is carried out. Results showed that the process has a high execution in aspects such as fractional water cost (TCF) and energy cost (TCE), as well as solvent reuse during extraction processes (SRI) and production yield, noting that the mentioned indicators are above 80%. In contrast, the metrics related to water management (FWC) and specific energy (ESI) showed the lowest performance. These discoveries support the use of optimization techniques like mass process integration. The energy-related indicators reveal that the process presents both benefits and drawbacks. One of the drawbacks is the energy source due to the high demand for electrical energy in the process, compared to natural gas. The specific energy intensity indicator (ESI) showed an intermediate performance (74%), indicating that the process consumes high energy. This indicator enables us to highlight that we can find energy aspects that require further study; for this reason, it is suitable to say that there is potential to enhance the energy efficiency of the process by applying energy integration methods.

Investigation of the substrate properties of fluorescently labeled pyrimidine triphosphates in recombinase polymerase amplification

Objectives. To study the substrate properties of Cy5-labeled deoxynucleoside triphosphates of various natures (dU and dC) in the process of incorporation in the DNA chain during recombinase polymerase amplification (RPA).Methods. The work used the real-time RPA method. The method of horizontal electrophoresis was used to control the quality of the amplification products obtained.Results. The influence of the fluorophore structure and linker lengths on the substrate properties for deoxynucleoside triphosphates Cy5-dUTP and Cy5-dCTP was studied. The following values of the substrate efficiency parameters were determined: amplification efficiency (kinetic indicator), normalized product yield, and embedding coefficient.Conclusions. Modified deoxynucleoside triphosphates (dNTP) with long linkers between the fluorophore and the nitrogenous base, as well as between the quaternary ammonium group and the second heterocycle of the fluorophore, showed greater substrate efficiency than fluorescently labeled dNTP with short linkers. The modified dU in each pair demonstrated greater substrate efficiency compared to the modified dC.

CUTTING EFFECTS ON ALFALFA (MEDICAGO SATIVA) GROWN UNDER UREA WITHOUT RHIZOBIUM MELILOTI FORAGE DYNAMICS

In order to see the effects of cutting on the forage dynamics of alfalfa to which urea was added instead of Rhizobium meliloti, this study was conducted in one year.A randomised full block design was used to conduct the trials. Four treatments were carried out with different doses of urea in experimental plots of 3 m by 1 m: a dose of 30g/plot; a dose of 40g/plot, a dose of 50g/plot and a last dose of 60g/plot. In addition to these treatments, there is the control which is alfalfa whose seeds have been inoculated.Forage production has fluctuated over the course of ten cuts done. The results are as follows : dose 1, the minimum obtained is 1597.71 kg DM/ha obtained in section 1 and the maximum is 2704 kg DM/ha obtained in section 5 ; dose 2, the minimum is 1943.97 kg DM/ha obtained in section 1 and the maximum is 3394.8 kg DM/ha in section 5 ; dose 3, the minimum obtained is 2424.00 kg DM/ha obtained in section 8 and the maximum is 4255.97 kg DM/ha in section 3; dose 4, the minimum is 2288.00 kg DM/ha in section 8 and the maximum is 4501.01 kg DM/ha in section 1. For the control, the minimum dry biomass obtained is 1549.00 kg DM/ha obtained in section 3 and the maximum is 2719.01 kg DM/ha obtained in section 3. In every cut, leaf/stem ratio was superior to 0.5. The results of this work show that cutting has a strong impact on alfalfa forage production. After this, alfalfa yield producted in this study is better than natural forage yield production, it means that alfalfa can be a solution for animal feed to face forage problems.

Simultaneous saccharification and fermentation for d-lactic acid production using a metabolically engineered Escherichia coli adapted to high temperature

BackgroundEscherichia coli JU15 is a metabolically engineered strain capable to metabolize C5 and C6 sugars with a high yield of d-lactic acid production at its optimal growth temperature (37 °C). The simultaneous saccharification and fermentation process allow to use lignocellulosic biomass as a cost-effective and high-yield strategy. However, this process requires microorganisms capable of growth at a temperature close to 50 °C, at which the activity of cellulolytic enzymes works efficiently.ResultsThe thermotolerant strain GT48 was generated by adaptive laboratory evolution in batch and chemostat cultures under temperature increments until 48 °C. The strain GT48 was able to grow and ferment glucose to d-lactate at 47 °C. It was found that a pH of 6.3 conciliated with GT48 growth and cellulase activity of a commercial cocktail. Hence, this pH was used for the SSF of a diluted acid-pretreated corn stover (DAPCS) at a solid load of 15% (w/w), 15 FPU/g-DAPCS, and 47 °C. Under such conditions, the strain GT48 exhibited remarkable performance, producing d-lactate at a level of 1.41, 1.42, and 1.48-fold higher in titer, productivity, and yield, respectively, compared to parental strain at 45 °C.ConclusionsIn general, our results show for the first time that a thermal-adapted strain of E. coli is capable of being used in the simultaneous saccharification and fermentation process without pre-saccharification stage at high temperatures.

Copper-Catalyzed Hydroamination of 2-Alkynylazobenzenes: Synthesis of 3-Alkenyl-2H-Indazoles.

A copper-catalyzed intramolecular synthesis of 3-alkenyl-2H-indazoles from 2-alkynylazobenzenes is described. The reaction proceeds in a single step via C-N bond formation and a subsequent 1,2-hydride shift, affording products in high yields. DFT calculations suggest the 1,2-hydride shift as the rate-determining step. Further derivatization enables functionalization of the 3-alkenyl-2H-indazoles.

Characterization of xanthan gum–metal complexes biosynthesized using a medium containing produced water and cassava processing residues

The use of residues from petroleum and crop industries is a feasible and sustainable alternative approach for the production of xanthan gum (XG). This study aimed to evaluate the biosynthesis of XG and the resulting final product obtained using Xanthomonas axonopodis pv. manihotis 1182 in a medium containing produced water (PW) and cassava processing residues. The combined use of PW and cassava crop residues was beneficial for XG production, achieving a product yield of 6.80 g L−1. The micrographs of recovered XG revealed the presence of elongated fiber-like microstructures rather than large agglomerates. The X-ray diffraction profiles of recovered xanthan comprised well-defined peaks rather than an amorphous halo. The thermogravimetry profiles revealed the presence of approximately 60 % of remaining solids in recovered xanthan, in contrast to 30 % in the commercial sample. All the samples demonstrated a pseudoplastic behavior; however, the consistency indices of the recovered samples were approximately 50-times lower than those of commercial XG. The emulsification indices of the recovered XG were > 50 % and comparable to those of commercial xanthan. In this study, for the first time, we obtained a complex XG–metal structure possessing a high emulsification capacity and low viscosity.

B-containing ionic liquid modified SBA-15 for CO2-epoxide coupling reaction metal-free catalysis

A novel external-skeleton B-containing ionic liquid modified SBA-15 catalyst BBN-Imi-SBA-15-I (BBN denotes borabicyclo[3.3.1]nonane, Imi represents imidazolium ionic liquid) was successfully constructed by a post-modification method for efficiently catalyzing CO2-epoxide coupling reaction under both metal- and solvent-free conditions. 5BBN-Imi-SBA-15-I (5 refers to the molar ratio of Si to B), thanks to its synergistic effects of Lewis acid, weak base sites from tertiary amine and quaternary ammonium, hydrogen bond group and nucleophilic group, displayed good catalytic activity with 97 % product yield and 99 % selectivity at 100 °C, 2 MPa in the absence of cocatalyst. The obtained catalyst demonstrated good recyclability during six consecutive catalytic runs, also presented generality for various mono-substitute epoxides. Through in-situ NH3 diffuse reflectance infrared Fourier transform spectroscopy (NH3-DRIFTS) characterization, the Lewis acidity of organo-boron was verified. Besides, kinetics research also proved the positive effect of multiple active components on efficient catalysis under milder conditions over SiO2-based metal-free catalysts.

A dehydration membrane reactor towards highly efficient LPG synthesis via CO2 hydrogenation

In recent years, CO2 hydrogenation has garnered increasing attention as a promising avenue towards the conversion of captured CO2 to valuable liquid chemicals, including CH3OH, CH3OCH3, and liquified petroleum gas (LPG). However, chemical conversion of CO2 has proven to be immensely challenging, resulting in low CO2 conversion (<35 %) and product yields (<15 %). H2O, unavoidably evolved during CO2 hydrogenation, imposes both thermodynamic and kinetic penalties on CO2 hydrogenation reactions via adsorption on catalyst active sites and promotion of undesirable reaction pathways. In this work, to greatly facilitate direct conversion of CO2 to LPG over a bifunctional Cu/Zn/Zr on Al2O3 (CZZA)/Pd-β-zeolite catalyst, a dehydration membrane reactor (MR) featuring a H2O-conducting Na+-gated nanochannel membrane was studied. Before the incorporation of the Na+-gated membrane, the CZZA/Pd-β-zeolite was unable to produce LPG at 280–310 °C and 14 bar, and the CO2 conversion was limited to < 35 %. In stark contrast, the MR exhibited CO2 conversion and LPG yield of 72.1 % and 51.7 %, respectively. The operating conditions of the MR were systematically investigated to determine the maximum achievable performance resulting in CO2 conversion and LPG yield as high as 90.2 % and 60.5 %, respectively. Furthermore, the LPG space–time yield (STY) at the optimized conditions was near that of the best-performing traditional reactors (TRs) in the literature but at 3 times and 8 times increased CO2 conversion and time factor (W/F), respectively. The MR in this work demonstrates the synergistic efficacy of combined H2O removal and CH3OH consumption towards highly efficient hydrogenation of CO2 for LPG production.

Scale-up of Sodium Persulfate Mediated, Nitroxide Catalyzed Oxidative Functionalization Reactions.

Oxidation is a valuable tool in preparative organic chemistry. Oxoammonium salts and nitroxides have proven valuable as reagents and catalysts in this endeavor. The objective of this study is to scale up the oxidative amidation, ester formation, and nitrile formation using nitroxide as an organocatalyst. Oxidative functionalization reactions were scaled from the 1 mmol to the 1 mole level. Sodium persulfate was used as the primary oxidant, and a nitroxide was employed as a catalyst. The products of the reactions were isolated in analytically pure form by extraction with no need for column chromatography. The oxidative amidation and esterification of aldehydes can be scaled up from 1 mmol to 1 mole effectively, with comparable product yields being obtained at each increment. This work shows that conditions developed on a small scale can be transferred to a larger scale without reoptimization. The oxidative functionalization of aldehydes to prepare nitriles is not amenable to direct scale-up due to the concomitant formation of significant quantities of the corresponding carboxylic acid, thereby compromising the product yield. Two of the three oxidative transformations studied here can be scaled up successfully from the 1 mmol to the 1 mole level.

C18‐DABCO‐AA: A Novel Brønsted Acidic Gemini Surfactant for the Environmental Benign Synthesis of 2,3‑Dihydroquinazolin‑4(1H)‑ones in Water at Ambient Temperature

AbstractWe have successfully synthesized a new acidic surfactant named C18‐DABCO‐AA, which contains octadecyl and acetic acid substituent on DABCO (1,4‐diazabicyclo [2.2.2] octane) unit, with an excellent yield. The synthesized surfactant was analyzed using FT‐IR, 1H NMR, and 13C NMR spectroscopic techniques. Its thermal behavior was analyzed by using the TGA–DTA technique. Our analysis indicates that the synthesized surfactant has excellent surfactant properties. Its critical micelle concentration (CMC) is 0.80 mM as determined by the conductivity method and UV–vis absorption measurement at 298.15 K. Surfactant also showed strong acidic properties with a pKa of 3.3. It is the best catalyst for the synthesis of 2,3‑dihydroquinazolin‑4(1H)‐ones (DHQs) in water at 40 °C. The synthesis is achieved via two‐component reactions of various aromatic aldehydes and anthranilamide in water at a CMC concentration of C18‐DABCO‐AA. The method was also extended for synthesizing DHQs via two‐component reactions of different ketones and anthranilamide under similar reaction conditions. The products were achieved in with yields ranging from good to excellent within 60–90 min. Additionally, the aqueous solution with C18‐DABCO‐AA was reused up to five times with a minor decrease in product yield. The present protocol is fast, energy‐efficient, and can be used on a large scale for synthetic purposes. Additionally, it boasts impressive environmentally friendly credentials.