Heterogeneous Catalytic System Research Articles

Probabilistic microkinetic modeling: Species balance equations for a catalyst surface containing multiple short-range order parameters to capture spatial correlations.

Adsorbed molecules on a catalyst almost always arrange themselves in a manner that is far from perfectly random, which gives rise to spatial correlations. These correlations are a result of the interactions between the adsorbed species (adspecies) as well as elementary processes such as diffusion and reaction events that shape the adspecies arrangements. Despite their importance, spatial correlations are usually ignored while writing species balance equations for the modeling of heterogeneous catalytic systems. Recently, we have introduced a probabilistic microkinetic modeling (p-MKM) framework that aims at incorporating spatial correlations in the form of a short-ranged order (SRO) parameter into species balance equations. Here, we extend the approach to catalytic systems of higher complexity, namely, longer interactions and multiple species. This is made possible by including multiple pair probabilities in the p-MKM model for the first time. The interplay between different SRO parameters is probed. An important consideration is how many pair probabilities should be included to capture the underlying complexity with sufficient accuracy.

A review of process of methanol carbonylation to produce acetic acid

Acidic corrosion plays a significant part in the compound business, particularly in the production of new substance fiber. As of now, the primary technique for creating acidic corrosive is the carbonylation of methanol utilizing iridium or rhodium organometallic edifices. The delegate techniques and the most recent advancement of methanol carbonylation to deliver acidic corrosion from two parts of homogeneous catalysis and heterogeneous catalysis are explored efficiently. The present homogeneous catalytic method and heterogeneous catalytic synthesis method using two different catalytic systems are introduced, followed in chronological order by the traditional method of producing acetic acid by carbonylation of methanol in the history of the chemical industry. The primary issues with producing acetic acid using conventional techniques are examined, including the product separation and the costly catalyst recovery. These issues can be resolved by developing and perfecting heterogeneous catalytic systems. The benefits and drawbacks of conventional techniques are broken down, the comprehensive summary and critical analysis of previous research provide comprehensive background knowledge, and the future exploration bearing is to work on the heterogeneous synergist framework to accomplish higher selectivity and preservation rate and work on financial proficiency.

A General and Highly Versatile Heterogeneous Pd-Catalyzed Oxidative Aminocarbonylation of Alkynes with Aromatic and Aliphatic Amines.

An efficient heterogeneous catalytic system for the oxidative aminocarbonylation of alkynes and amines in the presence of CO/O2 to afford substituted propiolamides has been developed. The active nanocatalyst, [Pd/Mg3Al-LDH]-300(D), is composed by Pd nanoaggregates (2-3 nm average particle size) stabilized over a partially dehydrated [Mg3Al-LDH] matrix. The methodology has resulted widely applicable, being the first catalytic system, either homogeneous or heterogeneous, able to activate not only aliphatic amines but also poorly-nucleophilic aromatic amines. In fact, >60 substituted propiolamides have been synthesized in good to excellent isolated yields through this methodology, being 27 novel compounds. An important characterization effort (XRD, 27Al MAS NMR, TGA, TPD-CO2, BET area, XPS, HAADF-HRSTEM and HRTEM) and optimization of the synthesis conditions of the optimal catalyst has been performed. This study, together with a series of kinetic and mechanistic essays, indicates that the optimal catalyst is composed by Pd(0) species stabilized in a partially dehydrated/dehydroxylated LDH material with a Mg/Al molar ratio of 3 and a small crystallite size. All the experimental data indicates that the in situ formation of [PdI2] active species in the material surface together with the presence of a matrix with the optimal acid/base properties are key aspects of this process.

Unlocking high-efficiency decontamination by building a novel heterogeneous catalytic reduction system of thiourea dioxide/biochar

Herein, we reported a new contaminant purification paradigm, which enabled highly efficient reductive denitration and dechlorination using a green, stable reducing agent thiourea dioxide (TDO) coupled with biochar (BC) over a wide pH range under anoxic conditions. Specifically, BC acted as both activators and electron shuttles for TDO decomposition to achieve complete anoxic degradation of p-nitrophenol (PNP), p-nitroaniline, 4-chlorophenol and 2,4-dichlorophenol within 2 h. During this process, multiple strongly reducing species (i.e., SO22-, SO2•- and e-/H•) were generated in BC/TDO systems, accounting for 13.3%, 9.7% and 75.5% of PNP removal, respectively. While electron transfer between TDO and H+ or contaminants mediated by BC led to H• generation and contaminant reduction. These processes depended on the electron-accepting capacity and electron-conducting domains of biochar. Significantly, the BC/TDO systems were highly efficient at a pH of 2.0–8.0, especially under acidic conditions, which performed robustly in common natural water constituents.

Solvent Effects on Heterogeneous Catalysis for the Selective Hydrogenation

AbstractSolvent effects add a new dimension for tuning the activity and selectivity of heterogeneous catalytic reactions, which is extensively employed in the hydrogenation of unsaturated compounds with multiple functional groups. In this concept, we briefly summarize recent developments on how the solvent effects affect the catalytic performance from the following aspects: 1) the polarity of the solvent can influence the interaction between the solvent and the reactant or intermediate; 2) the composition of mixed solvent can influence the reactivity of the reactant or intermediate; 3) solvent effect varies with the metal identity and support; 4) the solvent can induce surface modification of the supported catalysts. This summarization will provide insights into the rational development of efficient and selective heterogeneous hydrogenation catalytic system to realize the precise synthesis of desired chemicals.

Enhancing the performance of catalytic membranes for simultaneous degradation of dissolved organic phosphonates and phosphorous recovery: A fit-for-purpose loose nanofiltration design

In this study, we developed a loose nanofiltration catalytic membrane (LNCM) by incorporating nitrogen-doped carbon nanotubes (NCNT) into graphene oxide (GO) membrane (NCNT@GO-M) to activate peroxymonosulfate for efficient phosphonates degradation into phosphate, reducing phosphorus-based pollution and facilitating P recovery. The NCNT@GO-M exhibited superior permeability (76.7 L m−2 h−1 bar−1) due to its expanded pore size (1.60 nm). It integrated nanoconfinement and surface catalysis, improving the availability of surface-bound sulfate radicals for rapid Orth-P generation (kobs, 1.93 s−1), with the kobs being 2.4 times higher than that of the NCNT membrane catalytic system and 2626 times higher than the NCNT@GO heterogeneous catalytic system. The NCNT@GO-M also demonstrated excellent antifouling, self-cleaning, and anti-interference ability, effectively retaining humic acid with a molecular weight exceeding 3.6 kDa (∼62% removal of dissolved organic carbon), making it suitable for real-water applications. The development of LNCM shows great potential for transforming and recovery of the nutrients in wastewater.

Selective Adsorbent Design with Multifunctional Surfaces: Innovating Solutions for Heterogeneous Catalysis in Water.

Heterogeneous catalytic systems with water as the solvent often have the disadvantage of cross-contamination, while concerns about the purification and workup of the aqueous phase after reactions are rare in the lab or industry. In this context, designing and developing the functional selective solid adsorbent and revealing the adsorption mechanism can provide a new strategy and guidelines for constructing supported heterogeneous catalysts to address these issues. Herein, we report the stable composite adsorbent (Fe/ATP@PPy: magnetic Fe3O4/attapulgite with the polypyrrole shell) that features an integrated multifunctional surface, which can effectively tune the selective adsorption processes for Cu2+, Co2+, and Ni2+ ions and nitrobenzene via the cooperative chemisorption/physisorption in an aqueous system. The adsorption experiments showed that Fe/ATP@PPy displayed significantly higher adsorption selectivity for Ni2+ than Cu2+ and Co2+ ions, especially which exhibited an approximate 100.00% removal for both Ni2+ ions and nitrobenzene in the mixture system with a low concentration. Furthermore, combined tracking adsorption of Ni2+ ions and X-ray photoelectron spectroscopy characterization confirmed that the effective adsorption occurs via ion transfer coordination; the pathway was further validated at the molecular level through theoretical modeling. In addition, the selective adsorption mechanism was proposed based on the adsorption experiment, characterization, and the corresponding density functional theory calculation.

Facet and dual vacancy engineering-boosting BiOBr for enhanced CO2 and epoxide cycloaddition reaction under mild and cocatalyst-free conditions: Double substrate active sites and activated surface bromine ions synergy

Among the many strategies for CO2 resource utilization, the synthetic technology of cyclic carbonates with 100 % atom economy through CO2and epoxide is one of the most industrially viable routes, but its efficiency has been severely hampered by the lack of highly active catalytic sites. Moreover, due to the intrinsic thermodynamic stability and kinetic inertia of CO2 and the higher energy barrier of the ring-opening reaction of epoxides, the heterogeneous catalytic conversion of CO2 highly depends on harsh operating conditions, high temperatures and pressures, and the incorporation of cocatalysts. The development of efficient heterogeneous catalysts for CO2 conversion under cocatalyst-free and mild conditions has always been a challenge. Herein, we have proposed a synergetic strategy of facet and vacancy engineering for the construction of highly efficient heterogeneous catalyst BiO1-xBr1-y-(010) for CO2 cycloaddition, where introducing the OVs-BrVs pairs into typical (010) facets BiOBr with simultaneous surface Lewis acid sites Bi3+ and nucleophilic sites Br−. By combining theoretical calculations and a series of systematic experiments, such as CO2 temperature-programmed desorption, electron paramagnetic resonance and fluorescence probe analysis experiments, the introduced OVs-BrVs pair can not only form Bi3+-Bi(3-x)+ dual active sites on the surface, which activate PO and CO2 respectively to reduce the energy barrier of CO2 insertion, but also activate Br− near BrVs to enhance their nucleophilic attacking ability and reduce the energy barrier of epoxides ring-opening. As a result, the BiO1-xBr1-y-(010) with abundant surface OVs-BrVs pairs showed a high cyclic carbonates conversion of 99 % with 100 % selectivity under cocatalyst-free and mild conditions, far surpassing most heterogeneous catalytic systems. This work provides a completely new strategy to construct high-performance heterogeneous CO2 cycloaddition catalysts through a simple facet and vacancy engineering strategy to overcome the harsh operating conditions limitation and the use of cocatalysts.

Insight into the role of reactive species on catalyst surface underlying peroxymonosulfate activation by P–Fe2MnO4 loaded on bentonite for trichloroethylene degradation

In this study, bentonite supporting phosphorus-doped Fe2MnO4 (BPF) was synthesized and applied for PMS activation to degrade TCE. Morphology and structure characterization results indicated the successfully synthesized of BPF, and the BPF/PMS system not only featured high TCE removal (97.4%) but also high reaction rate constant (kobs = 0.0554 min−1) and PMS utilization (70.4%, kobs = 0.0228 min−1). According to the results of various experiments, massive oxygen vacancies on P–Fe2MnO4 alter its charge balance and facilitate the electron transfer process named adjacent transfer (direct electron capture by adsorbed PMS from adjacent TCE). Mn(III) is the main adsorption site for PMS, and the hydroxyl groups on the catalyst (Fe sites of P–Fe2MnO4, Si and Al sites of bentonite) can also offer binding sites for PMS. The hydrogen-bonded PMS on Fe(III) and Mn(III) sites will subsequently accept the discharged electrons to generate free radicals and high-valent metal species. Meanwhile, electron loss of HSO5− that chemically bonded to hydroxyl groups on bentonite will generate SO5•−, which will further produce 1O2 through self-bonding. the active species on the catalyst surface contribute 65% of TCE degradation in the heterogeneous catalytic oxidation system.

Surging efficient PMS activation through a COF-MOF dual immobilized catalytic platform: Synergy of enhanced electron transfer and adsorption-PMS activation

In heterogeneous catalytic systems used for peroxymonosulfate (PMS) catalysis, the effectiveness of the catalyst and the leaching rate of metal ions have gained considerable attention. Taking inspiration from the advantages of combining covalent organic frameworks (COF) and metal–organic frameworks (MOF) to facilitate charge transfer and metal immobilization, this study proposes an alternative method through immobilizing the catalysts with MOF and COF coating. The synthesis of Co-Fe3O4@UiO-66@TpBD was carried out with a pre-synthesizing method, followed by COF coating through a Schiff-based reaction. The introduction of MOF has largely limited the metal leaching from 7.85 mg/L to 1.03 mg/L, and the subsequent introduction of COF has enhanced electron transfer and adsorption of PMS, as well as a further reduction in the metal leaching from 1.03 mg/L to 0.50 mg/L. Impressively, the dual immobilization strategy has guaranteed a more stable utility and the materials showed comparable performances even after 5 cycles. Moreover, singlet oxygen (1O2) is the dominant reactive oxygen species responsible for the degradation through electrophilic substitution of Acetaminophen (APAP).

A Review on the Development of Polymer Supported Heterogeneous Palladium Materials for Organic Synthesis and Electrochemical Applications

Abstract:: This comprehensive review explores the advancements in catalytic transformation, focusing on the use of heterogeneous catalytic systems with a particular emphasis on polymeric-supported palladium (Pd) complexes. This study explores the limitations associated with conventional homogeneous reagents, emphasizes the transition to eco-friendly catalytic systems, and emphasizes the importance of Pd nanoparticles. These nanoparticles are particularly noteworthy for their distinctive properties, including elevated catalytic activity, making them promising for various applications in organic synthesis. The review thoroughly examines the design and synthesis of heterogeneous catalysts, emphasizing the crucial selection of safe and recyclable supports to augment the longevity and reusability of metallic catalysts. Diverse polymer varieties, including polystyrene (PS), polyethylene (PE), polyacrylate derivatives, polyethylene glycol (PEG), and grafted polymers, are investigated as viable supports for Pd complexes. The authors intricately describe the synthesis techniques for these polymer-supported Pd catalysts and furnish illustrative examples showcasing their effectiveness in organic transformation. This comprehensive review additionally highlights the synthesis of polymer-supported palladium (Pd) materials and discusses their applications in electrochemistry. The focus extends to the electrocatalytic properties of Pdbased polymeric nanomaterials, showcasing their effectiveness in glucose sensing, hydrogen peroxide detection, and the sensing of other biological analytes. Furthermore, the catalytic capabilities of Pd nanoparticles in various electrochemical applications, including wastewater treatment and electrochemical capacitors, are explored. Integrating polymer-supported Pd materials into these electrochemical processes underscores their versatility and potential contributions to advancements in catalysis and electrochemical sensing. Catalytic applications featuring polymer-supported palladium complexes with polymeric ligands in organic synthesis processes use the Sonogashira reaction, Suzuki-Miyaura coupling, Heck reaction, Catalytic asymmetric transformations, etc. The subsequent section of the paper focuses on the creation of polymeric palladium complexes, achieved by the complexation of polymeric ligands with palladium precursors. It delves into noteworthy examples of catalytic processes employing polymer-supported palladium complexes featuring polymeric ligands, emphasizing distinct polymers, such as PS, PE, polyacrylate derivatives, PEG, and grafting polymers. The review concludes by exploring catalytic asymmetric transformations using chiral palladium complexes immobilized on polymer supports and discusses various chiral ligands and their immobilization on polymer supports, emphasizing their application in asymmetric allylic alkylation. The review furnishes a comprehensive summary of recent advancements, challenges, and prospective avenues in catalytic oxidation facilitated by polymer- supported palladium catalysts with electrochemical applications.

Rational Design of Cobalt Phthalocyanine (CoPc)‐Anchored TiO2 Nanorods for High‐Efficiency Selective Catalytic Oxidation

AbstractQuinclorac is important precursor for pharmaceutical, agricultural, and synthetic chemistry. The state‐of‐art synthesis of quinclorac via condensation, chlorination and oxidative hydrolysis often uses homogeneous catalysts and strong acid oxidant agents to promote the catalytic oxidation, which requires huge manpower input for the late‐stage purification process and is usually environmentally unfriendly. In this work, we successfully fabricated a stable cobalt phthalocyanine (CoPc) Co‐based composite (CoPc/TiO2) by anchoring CoPc on the surface of TiO2 nanorods for the selective oxidation of 3,7‐dichloro‐8‐dichloro methyl quinoline (3,7‐D‐8‐DMQ) into quinclorac. More impressively, CoPc/TiO2‐2.5 %‐Mn‐Br exhibits a high selectivity of 91.9 % for the catalytic oxidation of 3,7‐D‐8‐DMQ to quinclorac in acetic acid, with a quinclorac yield of 86.4 %, which is approximately 2.43 times higher than that of pristine CoPc‐Mn‐Br. The obtained heterogeneous catalytic system shows good reusability. Detailed mechanistic investigations reveal that the system works through a free radical mechanism via the formation of Co2+/Co3+ redox cycles. This work provides a new understanding for the stabilization of reaction intermediates and facilitates the designs of catalysts for selective catalytic oxidation.

Operando Nuclear Magnetic Resonance (NMR) Studies of a Trickle-bed Reactor Using D-T2 Correlations.

Catalytic conversions in fine-chemical and pharmaceutical production are increasingly performed in trickle-bed rectors. Optimisation of these processes is usually based on end of pipe measurement made at specific residence times. This process is both time-consuming and the data sometimes challenging to interpret. In the present work, operando nuclear magnetic resonance (NMR) techniques both at the scale of the whole bed (global) and spatially resolved within the bed (local) are used to gain new insights into the catalytic conversion process under reaction conditions. Spatially resolved spectroscopic and diffusion-T2-relaxation (D-T2) methods interrogate local differences in chemical conversion and selectivity, and mass transport (molecular self-diffusion) respectively, thereby providing valuable information for process simulation models. This capability is demonstrated using the continuous flow three phase (gas-liquid-solid) hydrogenation of benzonitrile over a fixed bed of 0.5 wt% Pd/Al2O3 catalyst pellets yielding toluene and benzylamine. Global 1H spectroscopic and D-T2 were used to monitor chemical conversion and the approach to steady state; these were subsequently followed by spatially resolved 1H spectra and spatially resolved D-T2 correlations to examine the local differences in axial conversion and selectivity of the catalyst bed packing. At steady-state a global conversion of 63% was achieved with 65% and 25% selectivity to benzylamine and toluene respectively. Heterogeneities in the local (axial) conversion and selectivity differed by 31% along the total catalyst bed length. These techniques should be applicable to many three-phase heterogeneous catalytic systems provided that the T2 relaxation time of the reactants and products is not prohibitively small.

Constructing Cu+ and Lewis acid sites enabling the generation of highly reactive N‑oxyl radical for the efficient aerobic oxidation of alkylarenes

Developing heterogeneous catalytic systems with high performance for the oxygenation of C(sp3)–H bonds to carbonyls using molecular oxygen as the oxidant is highly desirable. In the present research, active Cu+ sites have been efficiently constructed based on layered double hydroxides (LDHs) through in-situ reduction during the coprecipitation. Simultaneously, the formed CuZn(Mg)Al-LDH(R) catalysts demonstrated the characters of increased amount of oxygen vacancy and surface Lewis acid site. The newly synthesized catalysts exhibited higher catalytic performance than the samples prepared via conventional method, and up to 49.4% improvement in specific activity was observed in the aerobic oxidation of ethylbenzene. The mechanism study including a series of control experiments, semi-in-situ FT-IR analysis, and EPR analysis, demonstrated that reactive •O2– species generated via the acceleration of Cu+ species, and activated the NHPI (N-hydroxyphthalimide) molecule to form active PINO (phthalimide N-oxyl) species. The oxygen vacancy was verified to be able to activate O2 molecule and promote the formation of active 1O2 species. The surface Lewis acid site was proposed to interact with NHPI molecule, enabling the generation of highly active PINO species. The catalytic system also has the advantages of catalytical and structural stability, recyclability, and tolerance of wide substrate scope. We believe that the synergistic effect between the highly active sites and Lewis acid sites in catalyst can open up new opportunities for the activation of inert C–H bonds via O2/NHPI system.

Hexanuclear nickel-substituted silicotungstate as heterogeneous catalyst for construction of benzimidazoles

The development of heterogeneous catalysts is very important for the chemical industry. [Ni0.5(en)] [Ni6(μ3-OH)3(en)3(H2O)6(B-α-SiW9O34)]·3.5H2O (Ni6en, en = ethylenediamine) is one of the representatives of those semi-open Ni6-cluster based polyoxometalates that could be easily synthesized and shows potential catalytic activity in heterogeneous catalytic system. In this work, Ni6en exhibited high stability and excellent catalytic activity in the condensation reaction of aldehydes and o-phenylenediamines at room temperature. A range of benzimidazole compounds could be isolated in good to excellent yields. Furthermore, this heterogeneous catalytic system could be scaled up to gram reaction, and Ni6en could be reused 5 times with no significant decrease in activity, showing its potential application prospect.

Metal-Free Nitrogen-Doped Mesoporous Carbons for the Mild and Selective Synthesis of Pyrroles from Nitroarenes via Cascade Reaction.

The cascade synthesis of pyrroles from nitroarenes is an attractive alternative strategy. However, metal catalysts and relatively high temperatures cover the existing reported catalytic systems for this strategy. The development of nonmetallic heterogeneous catalytic systems for the one-pot synthesis of pyrrole from nitroarenes under mild conditions is both worthwhile and challenging. Herein, we describe an exceptionally efficient method for the synthesis of N-substituted pyrroles by the reductive coupling of nitroarenes and diketones over heterogeneous metal-free catalysts under mild conditions. Nonmetallic NC-X catalysts with high activity were prepared from the pyrolysis of well-defined ligands via simple sacrificing hard template methods. Hydrazine hydrate, formic acid, and molecular hydrogen can all be used as reducing agents in the hydrogenation/Paal-Knorr reaction sequence to efficiently synthesize various N-substituted pyrroles, including drugs and bioactive molecules. The catalytic system was featured with good tolerance to sensitive functional groups and no side reactions such as dehalogenation and aromatics hydrogenation. Hammett correlation studies have shown that the electron-donating substituents are beneficial for the one-pot synthesis of N-substituted pyrroles. The results established that the outstanding performance of the catalyst is mainly attributed to the contribution of graphitic N in the catalyst as well as the promotion effect of the mesoporous structure on the reaction.

Nanofibrous Porous Organic Polymers and Their Derivatives: From Synthesis to Applications.

Engineering porous organic polymers (POPs) into 1D morphology holds significant promise for diverse applications due to their exceptional processability and increased surface contact for enhanced interactions with guest molecules. This article reviews the latest developments in nanofibrous POPs and their derivatives, encompassing porous organic polymer nanofibers, their composites, and POPs-derived carbon nanofibers. The review delves into the design and fabrication strategies, elucidates the formation mechanisms, explores their functional attributes, and highlights promising applications. The first section systematically outlines two primary fabrication approaches of nanofibrous POPs, i.e., direct bulk synthesis and electrospinning technology. Both routes are discussed and compared in terms of template utilization and post-treatments. Next, performance of nanofibrous POPs and their derivatives are reviewed for applications including water treatment, water/oil separation, gas adsorption, energy storage, heterogeneous catalysis, microwave absorption, and biomedical systems. Finally, highlighting existent challenges and offering future prospects of nanofibrous POPs and their derivatives are concluded.

Effect of physicochemical properties of carbons on the performance of bead-type Pd/C catalysts for furfural hydrogenation

In green heterogeneous catalytic systems, alginate has emerged as a promising material for transforming powder catalysts into solid forms because of its sustainability and non-toxicity. Herein, the effect of carbon supports, including activated carbon (AC), carbon black (CB), carbon nanotubes (CNT), and carbon nanofibers (CNF), on a bead-type Pd/alginate-carbon catalyst was studied. Bead-type supports were synthesized by alginate gelation, and Pd-supported bead-type catalysts were prepared by a chemical reduction method. The catalytic activity in the hydrogenation of furfural was evaluated. Physical properties such as the specific surface area and pore volume of the carbon support greatly influenced the properties of the bead-type Pd/C catalyst. Pd/CB-alginate bead (AB), which had the highest specific surface area and pore volume, exhibited the smallest Pd particle size and dispersion, resulting in the highest catalytic performance. Additionally, the catalyst exhibited the highest FF conversion of 99 % and tetrahydrofurfuryl alcohol selectivity of 92 % under 20 bar of H2 at 35 ℃ for 4 h.

Cu+-based composite metal oxides enable the efficient [4+2] annulation reactions between tertiary anilines and tetrahydrofuran

An efficient heterogeneous catalytic system for the [4 + 2] annulation reactions between tertiary anilines and tetrahydrofuran has been developed based on CuCoFe layered double oxide in the study. Cu+ species was believed to play the crucial role in the catalytic transformation, and synergistic effect between Cu and CoFe species was observed in the reaction. Various tertiary anilines could be tolerated by the present catalytic system. A series of control experiments were conducted to determine the reaction intermediates. A distinctive reaction mechanism has been described for the annulation reaction based on these results and kinetic isotopic effects experiments.

N-acetyl-PABA@Cu(II) supported on Fe3O4 as the new heterogeneous catalytic system to assist the MCR derived synthesis of 2,2-dimethyl-2H-[1,3]dioxino[4,5-b]pyrrol-4(7H)-ones heterocyclic scaffolds

The present work elicits the synthesis of 2,2-dimethyl-2H-[1,3]dioxino[4,5-b]pyrrole-4(7H)-ones derivatives catalyzed by heterogeneous Fe3O4 magnetic nanoparticles supported N-acetyl-PABA@Cu(II), which address the limitations of traditional organic synthesis approaches in terms of sustainable and efficient, resulting in improved yields, higher selectivity with no waste. The decorum embraces four-component reactions (4CRs) of amines, aldehydes, meldrum’s acid, and nitromethane facilitated by Fe3O4-N-acetyl-PABA-Cu(II) in the presence of ethanol (CH3CH2OH) as an ecologically benign solvent under ultrasonic irradiation at room temperature. Outstanding conversion rates and selectivity were attained by the heterogeneous catalyst through great catalytic performance. The simple work-up, easy catalyst recovery, and no base or additional activators were required. Characterization of the structures of synthesized compounds and catalysts was corroborated through different spectroanalytical techniques viz; FTIR, 1H &13C NMR, Mass elemental analyses, Energy-Dispersive X-ray Spectroscopy (EDX), Field-Emission Scanning Electron Microscope (FE-SEM), Powder X-ray Diffraction (XRD), Thermal Gravimetric Analysis (TGA), Differential Thermal Analysis (DTA), Particle size analysis and Zeta potential.