Synthesis Of Mesoporous Zeolite Research Articles

Synthesis of mesoporous zeolite Y using Sapindus rarak extract as natural organic surfactant for deoxygenation of Reutealis trisperma oil to biofuel.

Saponin is a plant-derived chemical with an amphiphilic glycoconjugate structure extracted from sapindaceae plants like Sapindus rarak. This study investigated saponin extract of Sapindus rarak as a natural template for formation of mesoporous zeolite Y. Surface area and mesoporosity of zeolite Y were improved with optimization of Sapindus rarak extract (SRE) concentration (Y-Ln; n = 2, 5, 10 or 15 mL), reaching 216.26 m2 mesoporous area and 0.214 cm3 g-1 mesoporous volume for Y-L10 samples. A different loading of Ni was impregnated onto Y-L10 zeolite to improve Lewis/Brønsted acidity as catalysts in the deoxygenation of Reutealis trisperma oil (RTO) into hydrocarbon fuels. Impregnating 15% Ni on NaY zeolite enhanced Lewis acidity to 0.4556 mmol g-1, producing 48.8% liquid oil with 85.43% degree of deoxygenation. A high selectivity towards C15 and C17 hydrocarbon was analyzed from liquid yield, indicating the contributing factor from Lewis acidity and mesoporosity to enhance deoxygenation and prevent the hydrocracking reaction.

Citronellal cyclisation to isopulegol over micro-mesoporous zsm-5 zeolite: effects of desilication temperature on textural and catalytic properties

In this work, desilication reassembly post treatment process was applied in synthesis of mesoporous zeolite with stable phase composition and applied it in citronellal cyclisation reaction for the production of isopulegol. The desilication and temperature effects were further investigated on physical and chemical characteristics of zeolite and compared them with catalytic activity. The desilicated zeolite samples have been characterized with the help of N2-adsorption, XRD, ICP-OES, pyridine adsorption and FTIR techniques. Its performance was explored by controlling operative parameters. Experimental outcomes exhibited that desilication of zeolite would led to formation of mesopores inside the stable zeolite framework structures without substantial damage of their internal composition. These changes facilitate mass transfer and catalytic activity with an increase in surface area, mesoporosity, pore size, pore volume, acidity, and Lewis acid sites. Optimum desilication temperature (80 °C) was found as a best for an comprising extra active and selective mesoporous zeolite catalyst for citronellal cyclisation. Thus, this type of zeolite material has shown 100% conversion (e.g. complete conversion of citronellal reactants to the desired products), 95% isopulegol selectivity and highest reaction rate (0.11 min−1). This study exhibits the mesoporous zeolite (MZ-80 °C) as one of the most effective catalyst for citronellal cyclization reaction based on assessment of catalytic performance relative to other commonly available options.

The Link between ZSM-5 Zeolite Crystallization and Mesopore Formation by Leaching.

Acid or base leaching are well-established tools in the synthesis of mesoporous zeolites. Previous studies suggest an inherent link between the structure-property relationship of mesoporous zeolites, that is, chemical resistance, pore diameter and distribution, with zeolite synthesis or crystallization conditions. The exact nature and/or origin of this link is currently however, poorly established. Here, we provide evidence how zeolite crystallization conditions influence the leaching behavior and thus structure of mesoporous zeolites. Electron microscopy and in situ small angle X-ray scattering both confirmed the crystallization of ZSM-5 to utilize both nanoparticles and oligomers as elemental building blocks. Utilization of these species is highly depended on supersaturation. The precursor solution of decreased water content favored a faster consumption of nanoparticles compared to its oligomers at the early stage of crystallization. Then the addition of oligomers can heal the surface imperfections and thus the resulting zeolite showed a higher resistance against acid leaching. In contrast, within the precursor solution of increased water content the slower consumption of nanoparticles led to crystals with a less robust rim. Defects existed in the rim due to limited healing by oligomers and, as such, mesopores can be created by the following post-treatment. Precise control over selected crystallization conditions can therefore further aid the design of optimized mesoporous zeolites.

Exploring the Synthesis of Mesoporous Stannosilicates as Catalysts for the Conversion of Mono- and Oligosaccharides into Methyl Lactate

Sn-beta zeolites are among the most promising catalysts for the conversion of biomasses due to their high Lewis acidity, which allows coordination to functionalized molecules and promotes cleavage and rearrangement reactions. For applications in biorefining zeolite porosity would ideally be optimized to avoid diffusional limitations, which otherwise may decrease reaction rates and restrict the conversion of bulky substrates. The synthesis of mesoporous zeolites can help alleviating limitations and is a central topic in heterogeneous catalysis, with many synthetic procedures for mesoporous zeolites proposed over the last decades. Here, we explore different syntheses routes to prepare Lewis acidic Sn-containing zeolites, and the main features of the prepared mesoporous materials are characterized. We investigate the correlation between different types of porosity and the activity for the conversion of sugars into methyl lactate. The monomer glucose, the dimer sucrose and the oligomer inulin are applied as model substrates for the reaction in order to probe the accessibility of molecules with different sizes to active sites in zeolites with different pore systems.

메조 세공 제올라이트 Y 합성 및 이를 이용한 중금속(Mn2+, Fe2+)의 흡착

메조 세공 제올라이트 Y 합성 및 이를 이용한 중금속(Mn2+, Fe2+)의 흡착

Synthesis of mesoporous zeolites in fluoride media with structure-directing multiammonium surfactants

Mesoporous zeolite beta in pure-silica form and its analogues, including aluminosilicate, stannosilicate, and titanosilicate, were synthesized at near-neutral pH in the presence of fluoride ion as a mineralizer and piperidinium-functionalized multiammonium surfactant as a zeolite structure-directing agent (SDA). During hydrothermal synthesis, the surfactant headgroup generated zeolite beta frameworks with a thickness of 9 nm while numerous surfactant molecules were self-organized to form a nanosponge-like mesostructure in a disordered manner. The mesopores generated after calcination to remove the surfactant were highly uniform and further tailored with diameters in the range of 3.2–4.5 nm according to the surfactant tail lengths. MFI zeolite was also synthesized with a nanosheet morphology using C16H33N+(CH3)2C6H12N+(CH3)2C6H13 as the SDA in fluoride media. The zeolite samples obtained in this manner exhibited remarkably enhanced thermal stability, Brønsted acid strength, and hydrophobic nature compared to those synthesized at a high pH using OH− as the mineralizer due to the reduced defect sites, as confirmed by 29Si MAS NMR and FT-IR measurements. Due to these advantages, the mesoporous zeolite beta obtained in the fluoride media exhibited high catalytic activity in esterification of oleic acid with methanol.

Synthesis of mesoporous zeolite Y nanocrystals in octahedral motifs mediated by amphiphilic organosilane surfactant

Hydrothermal synthesis of octahedron-shaped nanocrystalline zeolite Y in the presence of amphiphilic organosilane surfactant is described. The influence of parameters, such as the surfactant concentration, temperature and reaction time on the structure, size, surface area and porosity of the zeolite Y nanocrystals was systematically investigated. The role of surfactant was bifunctional, contributing towards the preferential crystal growth as well as the mesoporosity in the material. The morphology, structure and composition of the zeolite Y particles were thoroughly characterized by various techniques. Precise tailoring of size of the particles and pores was found to be an artifact of synthesis and processing parameters. A plausible mechanism for the formation and directional growth of octahedron-shaped nanocrystalline zeolite Y is proposed.

The Research on Lining Board Preparation of Mesoporous Zeolites

In this paper, uses composite template, through the hydrothermal synthesis of mesoporous zeolite, and N2 adsorption specific surface area measurement instrument, scanning electron microscopy ( SEM ) on mesoporous zeolite pore size, morphology characterization, the crystallization pressure, crystallization temperature, crystallization time on mesoporous zeolite pore size, specific surface area, morphology of the impact. The results show that : the selection of P123 composite beer yeast as template agent, under the condition of high pressure crystallization ( control crystallization pressure 2.3MPa ), crystallization temperature of 110°C, the crystallization time is 72h, prepared by 10nm, specific surface area pore size of 400m2 / g mesoporous zeolite.

Synthesis of Mesoporous Zeolite A by Resorcinol−Formaldehyde Aerogel Templating

Mesoporous zeolite A has been synthesized by using a template method with resorcinol-formaldehyde aerogels having three-dimensional mesopores. It was characterized with X-ray powder diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, and nitrogen adsorption/desorption. The pore size distribution calculated from the nitrogen adsorption isotherm is a bimodal distribution with micropores and mesopores. Field emission scanning electron micrograph observations confirm the presence of mesopores.

Synthesis of mesoporous zeolites and their application for catalytic conversion of polycyclic aromatic hydrocarbons

Three series of mesoporous aluminosilicate (Al-MCM-41) samples were synthesized using different aluminum sources including aluminum isopropoxide, pseudo boehmite and aluminum sulfate. Their catalytic activities were tested in the conversion of aromatic hydrocarbons including hydrocracking of 1,3,5-triisopropylbenzene, alkylation of naphthalene, and hydrogenation of naphthalene and phenanthrene. The three series of Al-MCM-41 samples behaved differently in acting as acidic catalysts and as supports. The Al-MCM-41 synthesized using aluminum isopropoxide was found to be the most promising acidic catalyst and good support for Pt catalyst.