Mobil Composition Of Matter No. 41 Research Articles

Enhanced optical and antimicrobial activities of mono Zn and bimetallic (Zn, Co), (Zn, Pd) ions modified MCM-41: structural and morphological investigation

Mono and bimetallic modified MCM-41(Mobil Composition of Matter No. 41): Zn-MCM (ZM), Zn/Co-MCM41 (ZCM), and Zn/Pd-MCM-41 (ZPM) molecular sieves were produced by a surfactant-assisted technique. The structural and textural features were examined through spectroscopic and analytical techniques. The XRD analysis indicated broadening of diffraction peaks and a shift towards higher 2-theta values in the metal-incorporated (M-MCM-41) samples, confirming the successful integration of metal atoms into the MCM-41 framework; it also highlighted the preservation of a hexagonal structure with reasonable regularity, emphasizing the influence of metal incorporation on the mesoporous architecture of MCM-41. N2 adsorption–desorption isotherms revealed type IV isotherms for all samples; the BET specific surface area decreased to 672.48, 667.90, and 562.50 m2/g in ZM, ZCM, and ZPM, respectively comparing to the unincorporated MCM-41 sample (1200 m2/g), indicating partial filling of mesopores by metal centers, as confirmed by TEM images. The diffuse reflectance spectra exhibited a noteworthy optical band gap reduction of MCM-41 (5.98 eV) upon the incorporation of Zn and Co/Zn ions, resulting in values of 5.86 and 5.24 eV, respectively, with refractive index values close to 2. Additional absorption bands energies are observed at 3.14, 3.18, and 1.70 eV in ZM, ZPM, and ZCM samples, respectively suggesting the suitability of the metal incorporated samples for the photocatalytic applications. The M-incorporated samples exhibited a decline in the transmission intensity accompanied by small shifts. The enhanced antimicrobial activity of the metal-incorporated samples, surpassing that of the pure MCM-41 against a variety of tested microorganisms, is attributed to the presence of incorporated metal species, which create a more acidic environment and substantially contribute to the heightened antimicrobial effectiveness. The ZM compound demonstrated potent inhibition against Bacillus cereus and Pseudomonas aeruginosa bacteria, displaying comparable efficacy to Ampicillin, as a reference antibiotic. Additionally, ZPM exhibited considerable inhibitory activity against Escherichia coli, surpassing the reference antibiotic and showing similar effectiveness against Bacillus cereus, Pseudomonas aeruginosa, and Salmonella typhimurium.

Catalytic Decomposition of CH4 to Hydrogen and Carbon Nanotubes Using the Pt(1)-Fe(30)/MCM-41 Catalyst

The catalytic decomposition of CH4 to H2 and carbon nanotubes (CNTs) was investigated regarding Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41 using a fixed-bed flow reactor under an atmosphere. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscope (TEM), and Raman spectroscopy were used to characterize the behavior of Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41. The hydrogen yield of Pt(1)-Fe(30)/MCM-41 was 3.2 times higher than that of Fe(30)/MCM-41. When 1 wt% of Pt was added to Fe(30)/MCM-41(Mobil Composition of Matter No. 41), the atomic percentage of Fe2p increased from 13.39% to 16.14% and the core Fe2p1/2 electron levels of Fe0 and Fe2+ chemically shifted to lower energies (0.2 eV and 0.1 eV, respectively) than those of Fe(30)/MCM-41. The Fe, Pt, Si, and O nanoparticles were uniformly distributed on the catalyst surface, and the average iron particle sizes of the Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41 were about 33.4 nm and 58.5 nm, respectively. This is attributed to the uniform distribution of the nano-sized iron particles on the MCM-41 surface, which was due to the suitable metal-carrier interaction (SMCI) between Fe, Pt, and MCM-41 and the high reduction degree of Fe due to the spillover effect of H2 from Pt to Fe. Pt(1)-Fe(30)/MCM-41 produced multiwalled CNTs and bamboo-shaped CNTs with high crystallinity and graphitization degree using the tip-growth mechanism, with an ID/IG ratio of 0.93 and a C(101)/C(002) ratio of 0.64.

Valorization of glycerol into glycerol carbonate using the stable heterogeneous catalyst of Li/MCM-41

The present study explored the catalytic activity of the heterogeneous catalyst for transesterification of glycerol into glycerol carbonate, a versatile compound. Transesterification of glycerol was investigated with different active metals (Li, La, Ce, Mg, K) impregnated on MCM-41 (Mobil Composition of Matter No. 41) framework. Among these, lithium incorporated MCM-41 proved the better catalytic activity towards the formation of glycerol carbonate. The shortening of a long-range hexagonal array was observed with active metal incorporation due to the accumulation of non-framework Li species in the MCM-41 structure. BET study revealed that Li/MCM-41 possess type IV hysteresis loop according to IUPAC standards. The average pore diameter was increased from 25.43 Å to 62.02 Å with active metal incorporation in the MCM-41 framework. The catalytic activity of Li/MCM-41 was observed by varying different weight ratios of active metal and the calcination temperature. The results demonstrated that 5 wt% Li impregnated on MCM-41, calcined at 450 °C, appeared to have a maximum yield of glycerol carbonate. Additionally, the influence of reaction operating parameters was also investigated. The results showed that 99 ± 1.89% glycerol conversion and 93.14 ± 2.52% glycerol carbonate yield was achieved at dimethyl carbonate-to-glycerol molar ratio of 3, catalyst dosage of 4 wt% (relative to glycerol mass) and a reaction temperature of 90 °C in 3 h. The recyclability and stability of the screened catalyst was also studied under optimized conditions. The activation energy of the catalyst was determined by solving the differential equation using MATLAB ODE15s tool, and the obtained value was 53.77 ± 3.26 kJ/mol. The E-factor and PMI (Process mass intensity) values of glycerol carbonate synthesis were determined as 1.16 and 2.16, respectively, which demonstrate the less waste generation during the process.

Ni-BTC metal-organic framework loaded on MCM-41 to promote hydrodeoxygenation and hydrocracking in jet biofuel production

To improve catalytic performance of metal active sites in hydrodeoxygenation and hydrocracking conversion of methyl palmitate into high-quality jet biofuel, Ni-1,3,5-benzenetricarboxylate (Ni-BTC) metal-organic framework loaded on MCM-41(Mobil Composition of Matter No. 41) was prepared to enhance the accessibility of Ni active sites, facilitating hydrodeoxygenation to increase alkane yield with suitable arene content. The distance (0.98 nm) between Ni active sites within Ni-BTC structure, which was much larger than that (0.20 nm) within Ni nanoparticles, enabled methyl palmitate with maximum molecule width of 0.68 nm to go through Ni-BTC crystalline plane and get access to Ni active sites more easily. Ni-BTC nanosheets newly assembled in pore channels of MCM-41 were beneficial to effectively screen chain molecules of alkane products. With the largest BET surface area of 1014.2 m2/g, the Ni-BTC@MCM-41 catalyst with 2.5 wt% nickel (2.5Ni-BTC@MCM-41) reduced the nickel metal consumption by 75% comparing to nickel nanoparticle loading (10Ni@MCM-41), but achieved the best catalytic performances through hydrodeoxygenation on Ni active sites and hydrocracking on -SiOH acid sites. The alkane yield increased from 23.3% to 33.9%, while arene yield reduced from 22.4% to 6.5% in jet biofuel products. This resulted in an overall jet biofuel yield of 53.2% with uniform distribution along carbon numbers. The higher heating value of jet biofuel products thus increased to a peak of 45.90 MJ/kg.

High temperature shape – Stabilized phase change materials obtained using mesoporous silica and NaCl – NaBr – Na2MoO4 salt eutectic

Thermal energy storage at temperatures above 400 °C is critical for efficient industrial processes and continuous solar thermal power generation. Phase change materials (PCMs) can be used for both latent heat storage and improved conversion efficiencies, but their use has been prevented by the large, 5–25 % change in molar volume. Herein, shape-stabilized PCMs are prepared using 20% wt. mesoporous silica matrices and NaCl–NaBr–Na2MoO4 salt eutectic. The pristine salt mixture has a total enthalpy of 216 Jg-1 divided into a solid-solid transition at 455 °C and solid – liquid transition at 522 °C. Six mesoporous silica materials of the MCM-41 (Mobil Composition of Matter No. 41), SBA-15 (Santa Barbara Amorphous) and mesocellular foam types were investigated as potential matrices for high temperature, shape-stabilized PCMs. All resulting composites have good thermal stability up to 650 °C. High – temperature optical microscopy shows that all samples retain their macroscopic solid shape above the salt melting point. Electron microscopy revealed a good dispersion of the silica matrix inside the molten salt phases. Both MCM-41 and SBA-15-type matrices yield PCMs with high total heat of fusion values between 169 – 178 Jg-1, in accordance to the 80% wt. salt fraction. The melting point is decreased with 5–10 °C for all composite materials, indicating nanoconfinement effects of the interparticle salt phase. This work therefore provides a new strategy for obtaining shape-stabilized materials useful for high – temperature heat storage.

Investigation of Isobutane Dehydrogenation on CrOx/MCM-41 Catalyst

The syntheses of MCM-41 (Mobil Composition of Matter No. 41) supported chromium oxide cat-alysts at different chromium concentrations (4–10 % by mass) were carried out hydrothermally. The aim of this study was to determine the effect of chromium concentration in the catalyst structure on the chro-mate types and chromium oxidation states, as well as the activity of the catalyst in the isobutane dehydro-genation reaction. Inactive α-Cr2O3 crystals for isobutane dehydrogenation were shown to increase in the catalyst structure as the chromium loading increased. The highest amount of Cr6+ on the catalyst surface was detected in the catalyst (H4-MCM-41) with 4 % chromium by mass. Catalytic tests (T = 600 °C, P = atmospheric pressure, WHSV = 26 h–1) were performed under fixed bed reactor conditions. The high-est isobutane conversion (~60 %) and selectivity (~80 %) were observed on the H4-MCM-41 catalyst, which had the highest amount of Cr6+ and monochromate structures. Catalyst deactivation was not due to coke deposition but, rather, was caused by the formation of inactive α-Cr2O3 crystal structures.

Response of Fibroblasts MRC-5 to Flufenamic Acid-Grafted MCM-41 Nanoparticles.

Recently, flufenamic acid (FFA) was discovered among fenamates as a free radical scavenger and gap junction blocker; however, its effects have only been studied in cancer cells. Normal cells in the surroundings of a tumor also respond to radiation, although they are not hit by it directly. This phenomenon is known as the bystander effect, where response molecules pass from tumor cells to normal ones, through communication channels called gap junctions. The use of the enhanced permeability and retention effect, through which drug-loaded nanoparticles smaller than 200 nm may accumulate around a tumor, can prevent the local side effect upon controlled release of the drug. The present work, aimed at functionalizing MCM-41 (Mobil Composition of Matter No. 41) silica nanoparticles with FFA and determining its biocompatibility with human fibroblasts MRC-5 (Medical Research Council cell strain 5). MCM-41, was synthesized and characterized structurally and chemically, with multiple techniques. The biocompatibility assay was performed by Live/Dead technique, with calcein and propidium–iodide. MRC-5 cells were treated with FFA-grafted MCM-41 for 48 h, and 98% of cells remained viable, without signs of necrosis or morphological changes. The results show the feasibility of MCM-41 functionalization with FFA, and its potential protection of normal cells, in comparison to the role of FFA in cancerous ones.

Development of ionic liquid and lithium salt immobilized MCM-41 quasi solid-liquid electrolytes for lithium batteries

Li-ion conducting quasi solid-liquid electrolytes (QS-LEs) containing ionic liquid EMIMTFSI, lithium salt LiTFSI and ordered mesoporous MCM-41 (Mobil Composition of Matter no. 41) have been synthesized and characterized by N2-sorption, SEM, TEM, DSC, TGA, and complex impedance spectroscopy techniques. The results show that the synthesized QS-LE has good thermal stability (∼360°C; onset temperature) and a wide electrochemical window ∼5.23V. The ionic conductivity is increases with increasing the amount of Li-IL (LIL) solution and attains a value of ∼6.37×10−4Scm−1 at 30°C and 1.60×10−3Scm−1 at 70°C for QS-LE containing high amount of LIL solution. The high ionic conductivity is attributed to the enormous adsorption of LIL solution on the external surface and in the ordered mesopores channels of the MCM-41. A high total ionic transference number (∼0.99) and cationic transference number (tLi+∼0.35) for QS-LE containing high amount of LIL solution have also been obtained. Furthermore, the QS-LE displays outstanding electrochemical properties (specific capacity ∼153mAhg−1 at C/10 rate; and good high rate capability ∼100mAhg−1 and 83mAhg−1 at 1C and 2C rate respectively) and battery performance with LiFePO4 cathodes.

Synthesis, characterization of Nafion-functionalized MCM-41 and its catalytic application in preparation of CL-20 via HNO3 electrolyte involved nitration of TAIW

Hybrid organic–inorganic MCM-41 (Mobil Composition of Matter No. 41) silicas functionalized with Nafion (perfluoroalkylsulfonic acid analogous) were prepared and characterized by Fourier Transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and N2 adsorption analysis. The Brønsted acidity was determined by UV spectrophotometer. The prepared catalyst (SA/MCM-41) exhibited high catalytic activity in the nitration of TAIW (tetraacetylhexaazaisowurtzitan) aiming at synthesizing CL-20 (hexanitrohexaazaisowurtzitane), with the yield up to 93%. The leaching problem was not observed after several runs, demonstrating that the catalyst could be recycled and reused without losing activity.

Hyperpolarized 129Xe NMR as an Alternative Approach for Investigating Structure and Transport in Ordered Mesoporous Materials Prepared via Pseudomorphic Transformation

The stepwise pseudomorphic transformation of silica gel and porous glass into MCM-41 (Mobil Composition of Matter No. 41) has been investigated for the first time with hyperpolarized 129Xe NMR. The changes in structure were followed by changes in the line shape and chemical shift of the 129Xe NMR signals, whereby variable temperature (VT)-NMR and selective 1D exchange spectroscopy (EXSY) experiments revealed differences in the mechanism of the transformation, depending on the starting material.

Reduction of toxic Cr(VI)-humic acid in an ionic liquid

Remediation of soil contaminated by toxic hexavalent chromium species associated with humic acid (Cr(VI)-HA) and absorbed Cr(VI) in pores frequently experiences technical difficulties. In the present work, a feasibility study for extraction of the Cr(VI) species from a molecular sieve MCM-41 (Mobil Composition of Matter No. 41) that was used to simulate the pore system of soil, with a green solvent (ionic liquid), 1-butyl-3-methylimidazolium chloride ([C4mim][Cl]), was carried out. After a 30-min extraction, approximately 70% of the Cr(VI) species can be extracted. By component fitted X-ray absorption near edge structure (XANES) spectroscopy, about 48% of the Cr(VI)-HA are reduced to form less toxic species (Cr(III)-HA) during extraction with [C4mim][Cl]. Note that the Cr-O in the [C4mim][Cl] phase has a slightly greater bond distance (BD) (0.162nm) possibly due to the fact of that the fraction of Cr(III) is increased in the extraction process. The non-extractable chromium remaining in MCM-41 has a much greater fraction of Cr(III) (78%) and its BD is further increased to 0.195nm. The coordination numbers of chromium for the 1st shell Cr-O in the Cr(VI) and Cr(III) species are in the range of 2.4–2.9, suggesting that chromium is chelated with HA and adsorbed in MCM-41. The 1H NMR data also suggest that the enhanced reduction of the Cr(VI) species may be related to interactions between chromium species and electron-rich imidazole ring of the [C4mim]+. This work also exemplifies that the fate of toxic chromium species in the complicated remediation of contaminated soils can be revealed in a molecule-scale study by synchrotron X-ray absorption spectroscopy.

Development of low-density polyethylene antioxidant active films containing α-tocopherol loaded with MCM-41(Mobil Composition of Matter No. 41) mesoporous silica

Antioxidant active packaging films are always prepared to help protect fatty food safety. In this study, a new LDPE (Low-Density Polyethylene) film containing α-tocopherol adsorbed on MCM-41 mesoporous molecular sieve was prepared by extrusion. The synthesized MCM-41 were thoroughly characterized before and after loading with α-tocopherol by powder X-ray diffraction, nitrogen adsorption isotherms, infrared spectroscopy, and thermogravimetric analysis. Physical properties of the new films including tensile strength, oxygen and water barrier properties were studied. In particular, the effect of loading α-tocopherol onto MCM-41 on the migration behavior of α-tocopherol from active films was investigated. Migration test were performed at 40 °C, using 95%(v/v) ethanol as fatty food simulants on LDPE films with pure α-tocopherol and the assembly of α-tocopherol and MCM-41. The results showed that, after being adsorbed on MCM-41, the releasing period of α-tocopherol in LDPE were prolonged by about 36%, and the diffusivity of the antioxidant decreased by 53%. Moreover, DPPH radical scavenging assay proved the effectiveness of the antioxidant in the new film. These demonstrated that the new kind of active film can be potentially used for controlled release antioxidant food packaging application.

Synthesis, Characterization and Application of N-Ti/13X/MCM-41 Mesoporous Molecular Sieves.

Di-n-butyl phthalate (DBP) is a type of phthalate ester. In recent years, an increasing number of studies have examined the removal of DBP. In this study we use a composite material of N-Ti/13X/MCM-41, synthesized by nitrogen, molecular sieve 13X, tetrabutyl orthotitanate and tetraethyl orthosilicate as raw materials, CTAB as a structural template and tetrabutyl titanate and urea under hydrothermal conditions. The optimized experimental conditions, such as the amount of material, reaction time, pH value and initial concentration were tested. The surface areas of N-Ti/13X/MCM-41 were found to be 664 m2g(-1). TEM micrographs revealed N-Ti/13X/MCM-41 is consisting of aggregates of spherical particles, similar with standard synthesized MCM-41 (Mobil Composition of Matter No. 41). Through photocatalytic degradation experiments, the optimum degradation efficiency of DBP was more than 90% at a pH 6.0 with catalyst dosing of 0.15 g L(-1).

Preparation and characterisation of MCM‐41 materials with intra‐wall cross‐mesopores

A series of novel mesoporous MCM-41 (Mobil Composition of Matter No. 41) materials has been synthesised using pre-organo-functionalised fumed silica as the silica source. Subsequent X-ray diffraction, nitrogen/argon adsorption and transmission electron microscopy analyses indicated that the additional mesopores formed in silica walls seem to cross the inherent hexagonally arranged channels, affording interconnected structural mesopores. Compared with the conventional MCM-41 material featuring single cylindrical pores, the newly prepared materials have a larger surface area (1450 m2/g), and their adsorption capacity for n-heptane has been enhanced in the low-pressure region, which presumably would be highly beneficial to the abatement of low-concentration volatile organic compounds.

SO2 Absorption Performance Enhancement by Ionic Liquid Supported on Mesoporous Molecular Sieve

TMGL (tetramethylguanidinium lactate) is believed to be a potential medium for SO2 removal. However, direct use of TMGL in SO2 absorption exhibits unsatisfactory absorption rate and desorption performance, mainly because of its hyperviscosity. In this work, mesoporous molecular sieve MCM-41 (mobil composition of matter no. 41) was employed as support material to prepare a novel absorbent (MCM-41-TMGL). The uptake of SO2 depends on TMGL, and the absorption rate depends on the porous feature of MCM-41-TMGL. Results show that MCM-41-TMGL dramatically improved the absorption kinetics and desorption efficiency, largely attributed to enhanced gas–liquid interface. Moreover, the absorbed SO2 in MCM-41-TMGL can be easily stripped out by heating at 90 °C under vacuum, allowing MCM-41-TMGL-10% to maintain 95% of the initial absorption capacity after 10 cycles of regeneration. In addition, the absorption performance of MCM-41-TMGL was investigated under different conditions, including absorption temperature, SO2 con...

Thermal, electrical and structural studies on ionic liquid confined in ordered mesoporous MCM-41

In the present study, immobilization of different amounts of ionic liquid (IL) 1-ethyl-3-methyl imidazolium tetrafluoroborate [EMIM][BF4] into the pores of ordered mesoporous MCM-41 (Mobil Composition of Matter no. 41) has been accomplished successfully.

Effect of Reaction Temperature and Catalyst Type on the Formation of Boron Nitride Nanotubes by Chemical Vapor Deposition and Measurement of Their Hydrogen Storage Capacity

Boron nitride nanotubes (BNNT) were synthesized over both Fe3+ impregnated MCM-41 (mobil composition of matter no. 41) and Fe2O3/MCM-41 complex catalyst systems at relatively low temperatures for 1 h by the chemical vapor deposition technique in large quantities. The formation of BNNT was tailored at different reaction temperatures by changing catalyst type. The use of Fe3+-MCM-41 and Fe2O3 as a complex catalyst system led to thin and thick tube formations. The diameters of BNNTs were in the range of 2.5–4.0 nm for thin tubes and 20–60 nm for thick tubes. The thin tube formation originated from the growth of BNNT over Fe3+-MCM-41 due to its average pore size of 4 nm. Higher reaction temperatures caused both BNNT and iron-based side product formations. The hydrogen uptake capacity measurements by the Intelligent Gravimetric Analyzer at room temperature showed that BNNTs could adsorb 0.85 wt % hydrogen which was two times larger than that for commercial carbon nanotubes.

Pyrolysis of soybean oil with H-ZSM5 (Proton-exchange of Zeolite Socony Mobil #5) and MCM41 (Mobil Composition of Matter No. 41) catalysts in a fixed-bed reactor

Abstract Soybean oil was pyrolyzed with various catalysts in a fixed-bed reactor under nitrogen flow at 420 and 450 °C. The H-ZSM5 catalysts (molar ratio SiO 2 /Al 2 O 3 = 28, 40, and 180) and 2 wt% (Ga, Al or Cu) impregnated MCM41 catalysts were used in order to investigate the effect of catalysts during the pyrolysis process. The gas products in all experiments were mainly methane, ethane and propylene. The liquid products in the presence of H-ZSM5 catalysts were mainly aromatic components while those with metal/MCM41 catalysts were a mixture of alkanes, alkenes, alkadienes, aromatic and carboxylic acids. The highest coke yield of 4.4 wt% was obtained with Ga/MCM41 catalyst at the pyrolysis temperature of 420 °C. The effect of catalysts on product yield and composition was systematically investigated.