Montmorillonite K10 Research Articles

PRELIMINARY ASSESSMENT OF THE PROCESSING OF HIGH-ACIDITY FATTY MATERIALS USING SOLID CATALYSTS FOR THE OBTAINMENT OF FATTY ACID METHYL ESTERS

Abstract This work presents the processing of a high-acidity oil through sequential reactions of esterification using montmorillonite K10 and transesterification using zinc monoglycerolate. Since these solids had not been employed along with this approach beforehand, the objective of this work is to provide a general insight of the proposed process and demonstrate its technical feasibility. In this sense, the processing of a synthetic mixture containing soybean oil and lauric acid provided a reduction of the free fatty acid content from (40.8±0.1) % to (3.1±0.4) % after the esterification reaction and a fatty acid methyl ester yield of (95.4±0.2) % was obtained after the transesterification reaction. As compared to traditional homogeneous catalysts, the solid catalysts employed in this work require higher reaction times to achieve satisfactory ester yields but, on the other hand, they are less sensitive to the presence of both water and free fatty acids in the raw materials and can be easily recovered and reused. Therefore, the results accomplished may help the development of a technology for processing high-acidity fatty materials in order to obtain biodiesel, although its economic feasibility still needs a further assessment.

Pentachlorophenol removal from aqueous solutions using Montmorillonite modified by Silane & Imidazole: kinetic and isotherm study.

Removal of pentachlorophenol (PCP) from wastewater containing chlorophenols, due to its toxicity, mutagenic and carcinogenic properties, has been attracted much interests of researchers. In this research, K10 montmorillonite was modified by silane and imidazole (Im) for increasing the removal percentage of PCP from aqueous solutions. It was characterized by FTIR, XRF, FESEM, EDS, and BET techniques. The influence of different parameters such as initial concentration, contact time, adsorbent dosage, pH, temperature and agitating speed was investigated. The maximum removal percentage (95%) were obtained for PCP at pH = 4. The isotherm experimental data for pentachlorophenol was best fitted using the Langmuir model and the kinetic studies were better described by the pseudo-second-order kinetic model. The thermodynamic study indicated that the adsorption of PCP by the adsorbent was feasible, spontaneous and exothermic. In this study, the modified montmorillonite by silane and imidazole is appropriate and low cost adsorbent for increasing of the removal percentage of PCP from aqueous solutions.

Regioselective synthesis of C-prenylated flavonoids via intramolecular [1,3] or [1,5] shift reaction catalyzed by acidic clays

Prenyl side chain and dihydropyrano skeleton exists in many natural and synthetic biologically active flavonoids. A highly efficient and regioselective method for the synthesis of C-prenylated flavonoids via intramolecular [1,3] or [1,5] shift reaction of 5-O-prenylflavonoids catalyzed by Florisil or Montmorillonite clays is described. Florisil catalyzes intramolecular [1,5] shift reaction of 5-O-prenylflavonoids to obtain 8-C-prenylated flavonoids exclusively, Montmorillonite K10 exhibits the superior selectivity to promote intramolecular [1,3] shift reaction to obtain 6-C-prenylated flavonoids compared with Florisil and Montmorillonite KSF. This method provides a practical process to regioselective synthesize biologically important C-prenylated flavonoids in good yields using commercially available and inexpensive catalyst under mild conditions.

Correction to: Removal of aluminum from aqueous solution by adsorption on montmorillonite K10, TiO2, and SiO2: kinetics, isotherms, and effect of ions

The original version of the article unfortunately contained mistakes in Table 1 and Table 2. Some parameters/constants in the tables are mistakenly in uppercase and there is a miswritten word in Table 2.

Structural and Thermal Properties of Montmorillonite/Ionic Liquid Composites.

Composites of montmorillonite K10 (MMT K10) and ionic liquid (IL) containing a 1-butyl-3-methyl-imidazolium cation ([BMIm]+) and various anions, such as bis (trifluoromethylsulfonyl) imide ([NTf2]−), trifluoromethanesulfonate ([OTf]−), and dicyanamide ([DCA]−) have been obtained in this work. A number of methods, such as dynamic light scattering (DLS), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermal gravimetry (TG), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, and nitrogen adsorption–desorption have been used to characterize clay, and to study the structure and thermal behaviour of the composites. It has been found that the MMT K10 powder has a narrow particle size distribution with a peak at 246 nm and a mesoporous structure (SBET=195 m2/g). According to the FTIR spectra, MMT K10/IL interaction depends on the IL type. It has been identified that confined ionic liquid interacts with both clay and adsorbed water in accordance with the hydrophilicity and size of the anion, in the following order: [DCA]− > [OTf]− > [NTf2]−. Characteristic temperatures of glass transition, crystallization, and melting have been determined for the ionic liquids under study and their MMT K10 composites. It has been revealed that when IL is adsorbed on the surface of clay, the phase transitions in IL change. The greatest changes are observed in the case of BMImNTf2. By applying the method of thermogravimetric analysis, it is shown that composite formation is accompanied by a decrease in the IL thermal stability. Apparently, the highly developed surface of montmorillonite K10, obtained by acid treatment, plays a major role in the decrease in the IL’s thermal stability. The influence of the IL anion on the thermal and spectral characteristics of an MMT K10/IL composite was studied for the first time.

Composite nanomaterials based on 1-butyl-3-methylimidazolium dicianamide and clays

Nanocomposites of ionic liquids with layered aluminosilicates represent a new class of functional materials that are promising when creating electrochemical devices, in environmental protection, in biomedicine, etc. Such nanocomposites contain environmentally friendly (clay) and easily regenerable components (ionic liquids), which makes them promising objects of green chemistry. In this paper, the interaction of 1-butyl-3-methylimidazolium dicyanamide ionic liquid with clays such as montmorillonite K10 (MMT K10), bentonite (Bent) and halloysite (Hal), which have a different molecular and mesoporous structure, as well as particles of different size and shape, was studied for the first time. Physicochemical methods such as FT-IR, TG, DSC, electron microscopy, viscosimetry and conductometry were used. The effect of the confinement of ionic liquid in the pores and immobilization on the surface of clays on the physicochemical properties of nanocomposites has been revealed. It was found that the interaction of ionic liquid with clays depends on the type of nanoclay, and the interaction strength changes in the following order: MMT K10 ≈ Bent >> Hal. The resulting materials have the properties of pseudoplasticity, high ionic conductivity, which is promising when creating electrochemical devices. At low temperature, the electrical conductivity of the halloysite-based composite is higher than that of a pure ionic liquid. The conductivity of the studied materials obeys to a general trend, which depends on the specific interactions and the properties of the clay-filled ionic liquid.

Catalytic Study of Hexadecane Cracking over Novel and Efficient HY/Al-HMS/K10 Hybrid Catalysts

The aim of this study is to provide a new and high-performance catalytic system for the cracking process by combining HY-zeolite, Al-hexagonal mesoporous molecular sieves (HMS) as a new matrix, and montmorillonite K10 as filler components. The Al-HMS molecular sieve was synthesized with different Si/Al molar ratios in the range of 2.5–35 and assembled with various amounts of HY-zeolite and montmorillonite K10 to prepare two- and three-component catalysts. After calcination, their catalytic activities were investigated in a cracking reaction of n-hexadecane at 500 °C and atmospheric pressure as a model reactant. The structure and surface properties of the synthesized catalysts were characterized by X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller, temperature-programmed desorption of NH3, and pyridine-IR techniques. Results indicated that the desired hybrid catalysts were successfully synthesized with the micro-mesoporous structures, high surface area, and suitable pore volume, and t...

Removal of catalyst poisons for the production of sugar alcohols from a real biomass molasses using a heterogeneous Ni catalyst

Molasses is an abundant biomass waste that remains after the manufacture of sucrose in sugar industries. This material still contains a large amount of sucrose, which is an attractive feedstock for the production of renewable chemicals. However, such real biomass often contains impurities that work as catalyst poisons in the chemical conversion, and thus the study on the effect of catalyst poisons and their removal is crucial to establish biorefinery. Herein, we report the pretreatment and catalytic conversion of sugarcane molasses to synthesize sugar alcohols (sorbitol and mannitol) that are versatile precursors to chemicals. In the adsorption pretreatment of molasses, Montmorillonite K10 selectively reduced organosulfur and organonitrogen compounds with no adsorption of sugars. Pristine molasses gives a low yield of sugar alcohols with low selectivity in the presence of a sponge nickel catalyst, but the pretreated sample provides up to 84% yield after optimization of reaction conditions. The correlation between the content of impurities and hydrogenation activity, controlled experiments, and density functional theory calculations show that organosulfur compounds are the main catalyst poisons due to the strong adsorption on nickel by the electron donation from S 3s3p hybrid orbitals to Ni unoccupied ones predominantly consisting of 4p.

Removal of aluminum from aqueous solution by adsorption on montmorillonite K10, TiO2, and SiO2: kinetics, isotherms, and effect of ions

Montmorillonite K10, TiO2, and SiO2 adsorption capacities for aluminum removal from acidic aqueous solution were studied. The effect of pH, initial aluminum concentration, adsorbent amount, contact time, and ions Ca2+, Mg2+, SO42−, HCO3−, Na+, Cl− were investigated. The experiments showed that tested adsorbents exhibited maximum capacities at pH 4.0. Over the studied adsorbent concentration range of 1.0–5.0 g L−1 the maximum aluminum uptake up to 97.4% was achieved by using 5.0 g L−1 of K10 while the same amount of TiO2 or SiO2 removed 71.9% and 94.6%, respectively. Several isotherm models were examined, and equilibrium data were found matching Freundlich model, whereas K10 data were also reasonably described by Langmuir and Sips isotherm models. The effect of ions on aluminum adsorption by 2.0 g L−1 of K10, TiO2, and SiO2 at pH 4.0 showed that Ca2+ ions presented in the solution lowed the removal efficiency of aluminum by materials tested. The adsorption capacity of K10 was influenced the most—the aluminum removal decreased by more than 50%. For TiO2 and SiO2 the reduction of aluminum removal was less—from 53.7 to 44.5% and from 65.5 to 47.4%, respectively. It was found that aluminum removal by both K10 and SiO2 was also influenced by Mg2+ ions and decreased the efficiency of adsorbents. The presence of HCO3− ions reduced the aluminum removal by TiO2 from 53.7 to 17.5%, while no apparent negative effect of HCO3− ions was observed for K10 and SiO2.

NO oxidation over Fe-based catalysts supported on montmorillonite K10, γ-alumina and ZSM-5 with gas-phase H2O2

The catalytic gas-phase H2O2 oxidation of NO was achieved over Fe-based catalysts supported on montmorillonite K10, γ-alumina and ZSM-5. ESR tests illustrate that the three catalysts can catalyze decomposition of H2O2 yielding highly reactive hydroxyl radicals, of which Fe/K10 has the fastest rate, followed by Fe/γ-alumina. Fe3+ in Fe/K10 and Fe/γ-alumina show lower density of electron cloud due to a strong interaction between Fe3+ and the support, which benefits the electron transfer from the H2O2 to Fe3+, thus favoring the production of hydroxyl radicals. Fe species exist on the surface of Fe/K10 mainly in the form of Fe2O3, whereas Fe species of Fe/γ-alumina and Fe/ZSM-5 exist mainly in the form of Fe3O4, and it is found that Fe2O3 is more active than Fe3O4 in catalytic gas-phase H2O2 oxidation of NO. Interestingly, Fe/ZSM-5 has the lowest efficiency in generating hydroxyl radicals, its NO removal efficiency is 90%, which is much higher than 47.5% for Fe/γ-alumina and 62.3% for Fe/K10. In-situ IR results suggested that Fe/ZSM-5 are dual functional in oxidation of NO, that is, whether both Fe ion sites and Brønsted acid sites collectively provide the catalytic functionality. In the meantime, a possible reaction mechanism on catalytic gas-phase H2O2 oxidation of NO over Brønsted acid sites is proposed.

Synthesis of Malic Acid on Montmorillonite K10: A Langmuir–Hinshelwood Kinetic Study

To accelerate the reaction of hydration of fumaric acid (F) to produce malic acid (M), Montmorillonite K10 (MK10) was tested as a solid acid catalyst. The experiments were performed in a stirred pr...

Strongly proton exchanged montmorillonite K10 (H+-Mont) as a solid acid catalyst for highly efficient and environmental benign synthesis of biscoumarins via tandem Knoevenagel–Michael reaction

In this study, synthesis of micro/meso porous acid-activated montmorillonite K10 (H+-Mont) was carried out by the activation of Na+-montmorillonite with HCl (4 M) at the controlled conditions. The prepared H+-Mont clay was then characterized using FT-IR, SEM, EDX, XRD and BET analyses. SEM and BET surface analyses represented that by the acid-activation, adjacent layers of montmorillonite K10 (Mont K10) were exfoliated to tiny segments leading to raise of surface area and total pore volume in H+-Mont system rather than the alone Mont K10. Catalytic activity of the prepared H+-Mont clay was further studied as a potent solid acid catalyst for synthesis of biscoumarin materials via tandem Knoevenagel–Michael reaction of 4-hydroxycoumarin with aromatic aldehydes. All reactions were carried out in a mixture of H2O-EtOH (1:1) at room temperature to afford the products in high to excellent yields within 25–50 min.

Multicomponent One‐pot Synthesis of Oxadiazole Included Pyranopyrazoles as Promising Antioxidant Agents

Oxadiazole‐fused combinations are of great concern for the novelty of effective therapeutic agents. In this context, a series of oxadiazole included pyranopyrazoles were prepared under eco‐friendly synthetic way by using montmorillonite k10 as a catalyst. All the final outcomes were formed with good yields. Further, compounds screened for their antioxidant assay. Most of the compounds revealed promising activity. Among all outcomes, electron rich‐substituted compounds at para position demonstrated higher antioxidant activity than their corresponding ortho‐substituted compounds. All belongings concluded that this eco‐friendly path is preferable to prepare therapeutic compounds. Further, biotic results established that all these biologically active compounds fit for supplementary to develop exogenous antioxidant drugs.

Montmorillonite K10-Catalyzed Solvent-Free Conversion of Furfural into Cyclopentenones

A simple and eco-friendly montmorillonite K10 (MK10)-catalyzed method for the synthesis of cyclopentenone derivatives from biomass-produced furfural has been developed. The versatility of this protocol is that the reactions were performed under solvent-free conditions and in a short reaction time under heterogeneous catalysis. Montmorillonite K10 is mostly explored as a heterogeneous catalyst since it is inexpensive and environmentally friendly.

Environmentally benign one-pot multicomponent synthesis of 1,4-dihydropyridine derivatives applying montmorillonite K10 as reusable catalyst

Environmentally benign one-pot multicomponent synthesis of different 1,4-dihydropyridine derivatives using montmorillonite K10 has been achieved. The montmorillonite K10-catalyzed reaction of aromatic aldehyde, malononitrile, substituted aniline, and diethyl acetylenedicarboxylate in H2O–EtOH allows to obtain structurally diverse 1,4-dihydropyridines in high yields. Possibility to recover and reuse the acidic catalyst in up to five catalytic cycles has been demonstrated. Short reaction times, suppressed formation of side products, inexpensive and nontoxic solvent system, catalyst recovery, and simple workup procedure are the main advantages of the developed synthetic method.

Spectroscopic Evidence for the Involvement of a Radical Intermediate in the Friedel-Crafts Benzylation Using Ion-Exchanged K10 Catalysts

For Friedel-Crafts alkylation of aromatic hydrocarbons an ionic reaction path is considered as classical reaction mechanism. The alkylation with benzyl chloride in the presence of ion-exchanged K10 montmorillonite catalysts containing multivalent, reducible cations had an outstanding activity, therefore a radical initial step as a supplement to the ionic mechanism was proposed earlier. We made ESR investigations to clarify the existence and the nature of the suggested radical species. The ESR experiments verified that the reaction involves a radical step.

Montmorillonite K10 catalyzed highly regioselective azidolysis of epoxides: A short and efficient synthesis of phenylglycine

A series of β‐hydroxyazides were effectively synthesized from the regioselective ring opening of epoxides by sodium azide using montmorillonite K10 as a novel heterogeneous catalyst in aqueous acetonitrile in good to excellent yields. The utility of this method has been demonstrated by achieving a short synthesis of phenylglycine in 33.5% overall yield.

Multifunctional Smart Nanocolorants for Simultaneous Printing and Antibacterial Finishing of Cotton Fabrics

The presented work studied the synthesis a new multifunctional smart nanocolorant based on natural clay (montmorillonite K10), chitosan and metal nanoparticles (CuO, ZnO, TiO2 or Ag) using ultrasonic technology. The prepared nanocolorants were characterized for their particle size and properties. These nanocolrant were used in printing paste for application to cotton fabric before and after sonication. Surface morphology antibacterial activity and fastness properties were evaluated for treated fabrics. It is observed that fabrics printed with prepared materials after sonication acquire much smoother surface than those printed with prepared materials before sonication. The new hybrid particles are small enough to diffuse into fibers and they create high fastness properties. In addition, printed fabrics with hybrids particles are highly fixed on the fiber surface.

Alkaline–modified montmorillonite K10: an efficient catalyst for green condensation reaction of aromatic aldehydes with active methylene compounds

An efficient and reusable catalyst, alkaline–modified Montmorillonite K10, has been developed and used in the Knoevenagel condensation. A series of condensation reactions based on ultrasound irradiation of different types of active methylene compounds and a variety of aromatic aldehydes showed the high efficiency of the prepared catalyst. This protocol has notable advantages, such as being eco-friendly, the ease of the work-up and reuse of the catalyst. The isolated compounds were synthesized in high yields (83–100%) in a short reaction time and were obtained, after crystallization, in pure form (IR, NMR and GC) without further purification. When ethyl cyanoacetate was used as active methylene compound, the reaction is highly stereoselective with only E geometry.

An innovative and efficient method to synthesize meloxicam in one-step procedure with respect to the green chemistry

An improved procedure for the synthesis of meloxicam drug (methyl 4-hydroxy-2-methyl-2H-1,2-benzothiazol-2-amine-3-carboxylate 1,1-dioxide) was described in one-step using mainly impregnated montmorillonite K10 (MK10) with ZnCl2 as a heterogeneous catalyst. This innovative method was compared to the last described procedure employed in the manufacture of this anti-inflammatory drug by means of some metrics used in a first step of the evaluation process of the environmental impact of a chemical transformation. Apart from the yield, which was 90%, atom economy, waste, environmental factor, reaction mass efficiency and stoichiometric factor were calculated as 91.6%, 8.4%, 0, 8.1% and 1%, respectively. Interpretation of these metrics was given and highlighted the fact that the strategy used in the current study may be considered as an environmental-friendly and sustainable method that fits well in the green chemistry concepts.