K10 Clay Research Articles

Montmorillonite K10 clay promoted one-pot pseudo-five-component synthesis of 5-cyano-6-(phenylthio)-2-((1-phenylvinyl)imino)-4- aryl(or heteroaryl)-2H-pyran-3-carboxylic acid derivatives and their potential cytotoxic activity

Montmorillonite K10 clay promoted one-pot pseudo-five-component synthesis of 5-cyano-6-(phenylthio)-2-((1-phenylvinyl)imino)-4- aryl(or heteroaryl)-2H-pyran-3-carboxylic acid derivatives and their potential cytotoxic activity

Montmorillonite K10 clay accelerated green protocol for the pseudo-five-component synthesis of substituted imidazo[1,2-a]pyridines

An array of conjugated Imidazo[1,2-a]pyridines were synthesized via a one-pot, pseudo-five-component reaction incorporating aryl aldehydes, malononitrile, thiophenol or phenol, and acetophenone or acetyl derivatives stimulated by Montmorillonite K10 clay as an eco-friendly catalyst. The entire procedure involves the formation of two new rings, three C–N bonds, two C-C bonds, and one C–X bond. This strategy enables quick green access to functionally multifaceted imidazo[1,2-a]pyridine analogues while highlighting good yields, pure products, an expedient reaction condition, and the reusability of the catalyst up to two cycles. All of the synthesized compounds were characterized through 1H,13C NMR, mass spectrometry, and infrared spectroscopy techniques.

Understanding The Mechanisms Of Catalytic Reactions On K10 Clay: A Comprehensive Study

Understanding The Mechanisms Of Catalytic Reactions On K10 Clay: A Comprehensive Study

Effect of montmorillonite K10 clay on RNA structure and function

One of the earliest living systems was likely based on RNA (“the RNA world”). Mineral surfaces have been postulated to be an important environment for the prebiotic chemistry of RNA. In addition to adsorbing RNA and thus potentially reducing the chance of parasitic takeover through limited diffusion, minerals have been shown to promote a range of processes related to the emergence of life, including RNA polymerization, peptide bond formation, and self-assembly of vesicles. In addition, self-cleaving ribozymes have been shown to retain activity when adsorbed to the clay mineral montmorillonite. However, simulation studies suggest that adsorption to minerals is likely to interfere with RNA folding and, thus, function. To further evaluate the plausibility of a mineral-adsorbed RNA world, here we studied the effect of the synthetic clay montmorillonite K10 on the malachite green RNA aptamer, including binding of the clay to malachite green and RNA, as well as on the formation of secondary structures in model RNA and DNA oligonucleotides. We evaluated the fluorescence of the aptamer complex, adsorption to the mineral, melting curves, Förster resonance energy transfer interactions, and 1H-NMR signals to study the folding and functionality of these nucleic acids. Our results indicate that while some base pairings are unperturbed, the overall folding and binding of the malachite green aptamer are substantially disrupted by montmorillonite. These findings suggest that minerals would constrain the structures, and possibly the functions, available to an adsorbed RNA world.

Montmorillonite K10 Clay Accelerated One‐Pot Multicomponent Synthesis of Substituted 2‐Amino‐3,5‐dicarbonitrile‐6‐phenylsulfanylpyridines: Experimental and Theoretical Investigation

Abstract2‐Amino‐3,5‐dicarbonitrile‐6‐phenylsulfanylpyridines occupy a prominent place among the physiologically and biologically active scaffolds owing to their therapeutic applications in the treatment of Parkinson's disease, asthma, urinary incontinence, kidney disease, the Hepatitis B infections, Creutzfeldt–Jacob disease, cancer, hypoxia/ischemia and epilepsy. A one‐pot, multicomponent condensation of aldehydes, malononitrile, and thiophenol catalyzed by Montmorillonite K10 clay afforded 2‐amino‐3,5‐dicarbonitrile‐6‐phenylsulfanylpyridines in good to excellent yields. All the products could be well characterized on the basis of spectral studies. The catalyst could be recycled three times without affecting the yields and even in the fourth recycling of the catalyst, the yield decreases marginally. This approach manifests environmentally benign feasibility in contexts of enhanced yields, milder conditions, short reaction times, and reusability of the catalyst. A theoretical study of a synthesized compound at the B3LYP/6–31 + G (d) level is additionally reported. Following the computation of the fundamental vibrational wavenumbers and intensities, it became evident that the observed and calculated wavenumbers were in perfect accord. Employing the same DFT level, Frontier molecular orbital (HOMO‐LUMO) energies, global reactivity descriptors, and molecular electrostatic potential were estimated for assessing the reactivity and possible sites for electrophilic and nucleophilic molecules. The outcomes prove that the compound exhibits significant kinetic stability.

Azomethine ylide [3 + 2]-cycloaddition of 3-alkylidene-7-aza-2-indolone: Synthesis of 3,3′-dispiropyrrolidine- and 3,3′-dispiropyrrolizidine bis 7-aza-2-oxindoles

32 AY CA reactions of 3-alkylidene-7-aza-2-indalone with acyclic and cyclic AY’s generated in situ from 7-azaisatin/isatin and sarcosine/proline in the presence of Montmorillonite k10 clay afforded highly functionalized 3, 3′-dispiropyrrolidine- and 3,3′-dispiropyrrolizidine bis 7-aza and 2-oxindole in excellent yield. The structure of the representative cycloadducts was established by single-crystal XRD. A plausible reaction mechanism is provided. Significantly the final product forms with newly formed two quaternary spiro carbons and two stereogenic centers simultaneously.

Montmorillonite K10 Clay Catalyzed Synthesis of Novel β-Aminocarbonyl Compounds and Their Biological Evaluation.

An efficient and reusable green catalyst for the synthesis of β-aminocarbonyl compounds has been developed. In this new and greener approach, β-aminocarbonyl compounds (1a-1r) were obtained by Montmorillonite K10 clay catalyzed reaction of aryl amines, aliphatic/aromatic aldehydes and β-ketoesters. Molecular docking investigations were performed for all compounds (1a-1r) with the proteins PDB ID: 1JIJ and 1KZN for S. aureus and E. coli, respectively. For all compounds good to strong interactions with the active sites were observed. The biological activities of β-aminocarbonyl compounds were further assessed for their antibacterial and antioxidant activities. The results confirmed that β-aminocarbonyl compounds could be further developed into new drugs with potent antibacterial and antioxidant activities.

Cascade transformation of 4-hydroxymethyl-2-carene into novel cage methanopyrano[4,3-b]thieno[3,2-g]benzofuran derivative

Reaction of trans-4-hydroxymethyl-2-carene with thiophene- 2-carbaldehyde under heterogeneous catalysis by K10 clay affordsubstitutedmethanopyrano[4,3-b]thieno[3,2-g]- benzofuran, a complex 5-membered chiral cage heterocyclic compound containing two thiophene moieties. Its structure was determined by 1D and 2D NMR experiments (HSQC, HMBC, COSY, NOESY) and HRMS.

Michael addition of ethyl anthranilate and phenyl monothioanthranilate to acetylenic esters: experimental and theoretical results

The reaction of ethyl anthranilate with DMAD and with methyl propiolate in dichloromethane in the presence of ethylaluminium dichloride as catalyst at room temperature gives a mixture of the respective E- and Z-intermediate derivatives which do not cyclize even on refluxing for several hours. On carrying out the reaction in refluxing methanol in the absence of the catalyst, only one stereochemical isomer is obtained which is Z-intermediate indicating conversion of less stable isomer into the thermodynamically more stable derivative under these conditions. The resulting product did not cyclize even on refluxing in methanol in the presence of montmorillonite K10 clay catalyst. The reaction of phenyl monothioanthranilate with DMAD and with methyl propiolate gives similar results. A theoretical investigation of the reaction of ethyl anthranilate with methyl propiolate at the B3LYP/6-31 + G(d) level reveals that it occurs in five steps.

Molybdenum oxide modified montmorillonite K10 clay as novel solid acid for flow synthesis of ionone isomers

Molybdenum oxide modified montmorillonite K10 clay (Mt-K10) was developed to synthesize ionone isomers via cyclization of pseudoionone. A fixed bed flow reactor was used to convert the current homogenous batch process into a heterogeneous flow process. To increase the acidity, molybdenum oxide was loaded on Mt-K10. Since molybdenum oxide contains both Lewis and Bronsted acidity, the loading resulted in a higher acidity of 1% (w/w) MoO3/Mt-K10 catalyst compared to Mt-K10 alone. 1% (w/w) MoO3/Mt-K10 is new, green, and economical catalyst derived from ammonium heptamolybdate tetrahydrate as molybdenum precursor and using Mt-K10 as support. The support and catalyst were analyzed by various characterization techniques, including XRD, FTIR, NH3-TPD, BET, SEM, TEM, and XPS analysis. Thus, 100 % conversion of pseudoionone and 75 % selectivity of ionone isomers were obtained. 1% (w/w) MoO3/Mt-K10 catalyst could be easily prepared on a large scale and it is effective in the synthesis of isomers of ionone with higher selectivity in comparison with other solid acids.

Development of nickel and silver ceramic filters supported on K10 montmorillonite clay for water disinfection

Abstract This study aimed to obtain ceramic filters with bactericidal action for water disinfection. For this, aqueous suspensions of montmorillonite K10 clay were prepared at concentrations of 48%, 50%, and 52%. Later, these were impregnated into polymeric sponges in order to form the ceramic skeletons by using the replica technique. The ceramic filters were submerged in nickel resins doped with 0.25 and 0.50 mol% silver. These resins were obtained by the Pechini method and heat-treated at 600 and 700 ºC for 2 h. Moreover, techniques such as X-ray diffraction, particle size analysis, scanning electron microscopy, energy dispersive spectroscopy, compressive strength, water absorption, and apparent porosity were used to characterize the filters, and their performance was analyzed by a bactericidal test. The bactericidal test results showed that the filters impregnated with the resin containing 0.50 mol% of silver promoted the total elimination of the Staphylococcus aureus and Escherichia coli bacteria.

Robust composite coating with superior corrosion inhibitory performance on surgical grade 316L stainless steel in Ringer solution

316L stainless steel (SS) is used as an orthopedic implant biomaterial due to its properties such as superior tensile strength, fatigue strength, and fracture toughness. Although it possesses such remarkable properties, it is corroded in aggressive biofluids. Hence, with a view to combat corrosion of surgical grade 316L SS, 3-amino-5-mercapto-1,2,4-triazole (AMTa) and its Na-montmorillonite (Na-MMT) K10 clay composite were electropolymerized over its surface and its anti-corrosion performance was evaluated. The results of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies (PDS) revealed the enhanced protective behavior of the composite compared to the polymer which was guaranteed by the results of chronoamperometric studies and atomic absorption spectroscopy. The functionalities of electrochemically synthesized p-AMTa and its Na-MMT composite films were characterized by Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy results which supported the formation of the polymer by NH–NH and S–S linkages. The surface morphological studies of a bare and film-deposited 316L SS confirmed the protective layer formed over the SS surface. Further, the effect of concentration of monomer and Na-MMT on corrosion inhibition was also studied. Anticorrosive performance of the polymer and Na-MMT composite studied after 7 days of immersion in the Ringer solution revealed that composite-coated 316L SS could retain its protective performance.

Stereoselectivity Inversion by Water Addition in the −SO3H‐catalyzed Tandem Prins‐Ritter Reaction for Synthesis of 4‐amidotetrahydropyran Derivatives

AbstractA range of heterogeneous ‐SO3H functionalized catalysts including carbon and halloysite nanotubes, commercial K10 clay, Amberlyst‐15 etc. was investigated for the first time using as a model the Prins‐Ritter reaction of (−)‐isopulegol with benzaldehyde and acetonitrile producing 4‐amido derivatives of octahydro‐2H‐chromenes (as (S)‐ and (R)‐diastereomers). A strong effect of water addition prior the reaction on the overall selectivity and the ratio of isomers in the case of heterogeneous and homogeneous (p‐toluenesulfonic acid) catalysis was found for the first time. The yield of the (R)‐diastereomer sharply increased with increasing amount of added water, while the S‐isomer prevailed with a minimum amount of added water. Experimental results and DFT calculations clearly indicate a kinetic control for R‐amide formation. Typically synthesis of 4‐amidooctahydro‐2H‐chromenes requires subzero temperatures and toxic catalysts, which were avoided in the current work. Nevertheless, the yield of the desired products (up to 83 %) at 30 °C after water addition exceeded the values reported previously. Thus, adding water is a simple and a very effective method for controlling both the yield and stereoselectivity of the Prins‐Ritter reaction products under mild conditions.

Synthesis, photophysical and electrochemical properties of donor–acceptor type hydrazinyl thiazolyl coumarins

A practical green MCR strategy has been developed for the synthesis of D–A type hydrazinyl thiazolyl coumarins catalyzed by an environmentally compatible MMT K10 clay in water at RT.

Prins cyclization of (-)-isopulegol with benzaldehyde for production of chromenols over organosulfonic clays

Prins cyclization of (-)-isopulegol with benzaldehyde was investigated with sulphur containing halloysite nanotubes, K10 clays and Cloisite clays. The catalysts were characterized by TEM, SEM, XRD, XPS, pyridine adsorption desorption by FTIR, nitrogen adsorption. The most active catalyst was K10 modified with chlorosulphonic acid giving 95% selectivity to the desired chromenol at 90% conversion and 30 °C. Selectivity to chromenol was increasing with increasing Lewis acid site concentration while no linear correlation of chromenol selectivity with the Brønsted acid sites concentration was observed. The diastereoisomer R/S ratio of chromenols was the highest, 11.5, at 70 °C and 90% conversion over sulphur modified halloysite nanotubes exhibiting rather low acidity. A higher stability of the R-isomer confirmed by quantum mechanical calculations can partially explain preferential formation of the R diastereomer.Successful catalyst reuse was demonstrated with the best performing catalyst, organosilylated sulphur containing K10.

Synthesis of Substituted Isatins from the MBH Adduct of 1,5,6-Trisubstituted Isatins Using (2,4-Dinitrophenyl)hydrazine and K-10 Clay Explored as Protection-Deprotection Chemistry.

An interesting synthetic transformation of protection–deprotection chemistry in an isatin molecule is achieved. Morita–Baylis–Hillman (MBH) adduct formation used as protection of the C-3 position in the isatin molecule is reported. C–C bond cleavage in the MBH adduct of isatin with the help of phenylhydrazine and C=N bond cleavage in the phenylhydrazone derivative of isatin with the help of K10 clay are studied systematically and reported as deprotection.

Biodegradable and active nanocomposite pouches reinforced with silver nanoparticles for improved packaging of chicken sausages

Abstract This study reports the development of biodegradable PVA-montmorillonite K10 clay nanocomposite blend films with in situ generated ginger extract mediated silver nanoparticles. Photo-assisted method using sunlight irradiation was adopted for the rapid and eco-friendly in situ generation of ginger extract mediated silver nanoparticles in the composite. FTIR, XRD and SEM analysis were conducted to confirm the generation of AgNPs. The nanocomposite blend film had clear antimicrobial activity against common food borne pathogens S. Typhimurium and S. aureus. It also had superior mechanical properties, water resistivity and light barrier ability compared to control films. Indoor soil burial test revealed the nanocomposite blend would degrade completely within 110 days. The nanocomposite blend film was then fabricated into novel packaging pouches and found to be highly efficient in reducing the microbial burden in chicken sausage samples, compared to control polyethylene pouches, signifying its potentiality in extending the shelf life of chicken meat products.

Efficient Baeyer–Villiger Oxidation Catalysed by Silver Nanoparticles Stabilized on Modified Montmorillonite

Silver nanoparticles supported on modified montmorillonite clay (Ag-NPs@mont), were utilized as catalyst for the Baeyer–Villiger oxidation of various ketones with hydrogen peroxide as an oxidant under solvent free condition at room temperature. The modification of Montmorillonite K10 clay was carried out with HCl under controlled conditions for generating a high surface area porous matrix which acts as support for the in situ generation of Silver nanoparticles. The synthesized nanocomposite material was characterized by UV–Visible spectroscopy, powder XRD, SEM-EDX, TEM and N2 adsorption–desorption analysis. The catalyst can be recycled and reused several times without significant loss of their catalytic activity.

EVALUATION OF SWELLING PROPERTIES OF POLY (ACRYLIC ACID)/Zr-PILLARED K10 SUPERABSORBENT HYDROGEL

Zr- Pillared K10 (Zr-K10) was synthesized by using Montmorillonite K10 clay. Zr- pillared K10 based superabsorbent (Zr-PILC-SA) was synthesized by using Zr- pillared- montmorillonite K10 via graft copolymerization reaction of acrylic acid (AA). After preparation of the films of hydrogels of Zr- pillared K10, swelling studies were performed in distilled water and different pH values at room temperature to investigate swelling behavior of pillared clay based superabsorbent films. It was also obtained that Zr-K10 based superabsorbent was pH dependent and showed a reversible swelling behavior. The swelling behavior of Zr-K10-SA was increasing by decreasing amount of Zr-K10 in the hydrogel. SEM, FTIR and XRD analysis were conducted for further characterization of the Zr-PILC-SA. FTIR analyses lead to ester formation between Zr-K10 and SA. XRD revealed the morphology of the superabsorbent was exfoliated and the layers of clay dispersed on the composite. 

Cu2+ Montmorillonite K10 Clay Catalyst as a Green Catalyst for Production of Stearic Acid Methyl Ester: Optimization Using Response Surface Methodology (RSM)

Clay catalyst has received much attention to replace the homogeneous catalysts in the esterification reaction to produce fatty acid methyl ester as the source of biodiesel as it is low cost, easily available, as well as environmental friendly. However, the use of unmodified clay, in particular montmorillonite K10 (MMT K10), for the esterification of fatty acids showed that the acid conversion was less than 60% and this is not preferable to the production of biodiesel. In this study, synthesis of stearic acid methyl ester using Cu2+-MMT K10 (Cu-MMT K10) was successfully optimized via response surface methodo-logy (RSM) based on 3-variable of Box-Behnken design (BB). The parameters were; reaction time (5-180 minutes), reaction temperature (80-120 oC) and concentration of Cu2+ in MMT K10 (0.25-1 M). The use of RSM in optimizing the conversion of stearic acid was successfully developed as the actual experimental conversion of stearic acid was found similar to the actual values under the optimum conditions. The model equation predicted that the following conditions would generate the maximum conversion of stearic acid (87.05 %reaction time of 62 minutes, a reaction temperature of 80 oC and catalyst used is 1.0 M Cu-MMT K10. This finding can be considered as green catalytic process as it worked at moderate reaction temperature using low cost clay catalyst with a short reaction time.