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Catalytic oxidation is a key technology for the conversion of petroleum-based feedstocks into useful chemicals (e.g., adipic acid, caprolactam, glycols, acrylates, and vinyl acetate) since this chemical transformation is always involved in synthesis processes. Millions of tons of these compounds are annually produced worldwide and find applications...
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... variation of this process uses o-xylene instead of naphthalene with further variations in the used catalysts ( Figure 3). A xylene isomer is also used in one of the most important industrial oxidation reactions, the production of terephthalic acid from p-xylene ( Figure 4). The relevance of terephthalic acid is based on being the precursor to polyethylene terephthalate (PET), the highest volume synthetic fiber. ...
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... catalytic behavior of this highly interconnected intracrystalline meso/microporous material was investigated for the epoxidation of bulky cyclic olefins, cyclohexene, and cyclooctene, at 60 • C, by H 2 O 2 . When compared to other catalytic systems, 3DOm-I Ti-beta zeolite exhibited significantly improved catalytic performance, far beyond that of conventional solely microporous Ti-beta either in micro-or nano-sizes (M-Ti-beta an N-Ti-beta) and TS-1 ( Figure 24). 3DOm-I Ti-beta catalyst showed a considerable recyclability upon each catalytic run, up to the fourth cycle. ...
Citations
... The high potential of mesoporous zeolites is confirmed by numerous current review articles devoted to their synthesis, e.g., [1][2][3][4][5][6][7], their application in catalysis and adsorption in general [8,22,23], or in particular processes such as biomass conversion [24] or hydrocarbon oxidation reactions [25]. Despite the large amount of general scientific literature describing mesoporous zeolites, only a few reports focus on individual environmental catalysis reactions, bringing together the state of the art. ...
Mesoporous/hierarchical zeolites (HZs) are a relatively new group of materials, and interest in their application in catalysis is continuously growing. This paper presents recent achievements in the application of mesoporous zeolites in catalytic reactions of nitrogen pollutant conversion. The analysis presented includes processes such as selective catalytic reduction of NOx with ammonia (NH3-SCR, DeNOx), selective catalytic oxidation of ammonia (NH3-SCO, AMOx), and catalytic decomposition of N2O. Different zeolite topologies and methods of their modification focused on mesoporosity generation (e.g., desilication, dealumination, steaming, self-assembly techniques, and application of hard and soft templates) are reviewed and compared with respect to catalytic processes. Special attention is paid to the role of porous structure and acidity, as well as the form of deposited transition metals, in the catalytic activation of modified zeolites in the elimination of nitrogen pollutants from flue gases.
... Zeolites are characterized by a regular arrangement of tetrahedra, giving a three-dimensional arrangement of cages and pores. The dimensions of the pores and cages are within the range of microporosity, namely, measuring from 3 to 20 Å [47]. Moreover, they are characterized by a large specific surface area. ...
Alkaline earth metal oxide (MgO, CaO, SrO) catalysts supported on BEA zeolite were prepared by a wet impregnation method and tested in the transesterification reaction of rapeseed oil with methanol towards the formation of biodiesel (FAMEs—fatty acid methyl esters). To assess the influence of the SiO2/Al2O3 ratio on the catalytic activity in the tested reaction, a BEA zeolite carrier material with different Si/Al ratios was used. The prepared catalysts were tested in the transesterification reaction at temperatures of 180 °C and 220 °C using a molar ratio of methanol/oil reagents of 9:1. The transesterification process was carried out for 2 h with the catalyst mass of 0.5 g. The oil conversion value and efficiency towards FAME formation were determined using the HPLC technique. The physicochemical properties of the catalysts were determined using the following research techniques: CO2-TPD, XRD, BET, FTIR, and SEM-EDS. The results of the catalytic activity showed that higher activity in the tested process was confirmed for the catalysts supported on the BEA zeolite characterized by the highest silica/alumina ratio for the reaction carried out at a temperature of 220 °C. The most active zeolite catalyst was the 10% CaO/BEA system (Si/Al = 300), which showed the highest triglyceride (TG) conversion of 90.5% and the second highest FAME yield of 94.6% in the transesterification reaction carried out at 220 °C. The high activity of this system is associated with its alkalinity, high value of the specific surface area, the size of the active phase crystallites, and its characteristic sorption properties in relation to methanol.
... Over the last 10 years, the catalytic properties of zeolites have been explored in numerous catalytic reactions, and such porous materials are favorable candidates due to their reactant selectivity and longer catalytic life cycle. [17][18][19][20][21][22][23][24] Recently the effect of many zeolites has been investigated in benzylation of acetic acid reaction. Instead of mineral acids, zeolites like Beta, ZSM-5, Mordenite, USY, Y, X and Meso ZSM-5 (SO 3 H-CTAB)-MW [25][26][27][28][29] were employed as heterogeneous catalysts in benzylation reaction, owing to their high acidity, low corrosivity, strong thermal stability. ...
Hierarchical Beta zeolite with tailor‐made pore structure is prepared by post‐synthetic alkali (NaOH) treatment. XRD, FE‐SEM, ICP‐OES, ²⁷Al & ²⁹Si MAS NMR, and N2 sorption isotherms were used to explore the structural transformation of these materials. ICP‐OES analysis showed post‐synthetic base treatment resulting into tuning of the Si/Al ratio, thereby increasing the acidity of the sample. The acidic properties of materials were measured using acid‐base titration, Pyridine FTIR spectroscopy, and NH3‐TPD. Conversion of acetic acid to benzyl acetate by reacting with benzyl alcohol was studied using hierarchical and parent sample. The reaction was evaluated with theoretical and experimental approaches. Under optimum reaction conditions, desilicated Beta zeolite showed 93 % acetic acid conversion and 90 % benzyl acetate selectivity, as confirmed by GC and GC‐MS analyses. Theoretical analysis indicated direct relationship between rate constant and rising reaction temperature, in accordance with the principles of first‐order reaction kinetics (R²>0.95). The activation energy for acetic acid benzylation over Beta‐0.1 M NaOH was found to be 10.21 kJ mol⁻¹, considerably lower value compared to previous reports.
... Inferred from their extended catalytic lifespan and strong selectivity towards reactants, porous materials like zeolite are particularly interesting candidates, and their conversion and specificity in several catalytic reactions have been the subject of extensive study over the past several decades [22,23]. Recently the effects of many zeolites were investigated in benzylation of acetic acid reaction. ...
Micro-mesoporous Mordenite and ZSM-5 zeolites with tailor-made pore structures are produced using post-synthetic dealumination and desilication treatment. Inductively coupled plasma–optical emission spectroscopy (ICP-OES) analysis showed that post-synthetic acid and base treatment resulting into tuning the Si/Al ratio, thereby increasing the acidity of sample. Acidic characteristics of the samples were confirmed using pyridine FTIR and NH3− TPD. Acetic acid was converted to benzyl acetate by reacting with benzyl alcohol, over both hierarchical samples and their parent counterparts. Acid-modified zeolites were compared with those of base-modified one and also with the unaltered parent materials. Mesoporous pore volume of all zeolites significantly increased due to base alteration compared to the acid alteration and the parent samples. In other studies, the micro-/meso-H-ZSM-5 catalyst showed considerable potential for benzylation, exhibiting an impressive AA conversion rate of 94% with 95% benzyl acetate selectivity. In comparison, in the current study, an alternative catalyst consisting of base-altered Mordenite was found to surpass these results, achieving a 100% AA conversion and 98.2% selectivity towards benzyl acetate. Optimization of the process was investigated by altering time, temperature and catalyst amount. Analysis of reaction products was validated by GC and GC–MS. The reaction rate constants exhibited a positive correlation with increasing reaction temperature, as per the principles of first-order reaction kinetics (R² > 0.94); and activation energy for AA benzylation over Mor-0.1 M NaOH was found to be 13.87 kJ mol⁻¹, which is significantly lower than the previously reported value.
... Due to the presence of nano-diameter pores, the release of the complex is slow and can be controlled. The size of the cavity diameter is very effective in how it is released (Martins et al., 2022). It can be stated that HMSNs-treated by amine are suitable for the treatment of cancer which requires gradual and long-term clinical Pt-drug delivery (Machana et al., 2011). ...
In this project, drug release was examined based on the adsorption of cisplatin, carboplatin, oxaliplatin, and oxalipalladium on aminated mesoporous silica nanoparticles (N-HMSNs) and human serum albumin (HSA). These compounds were characterized by different techniques where three clinical Pt-drugs, cisplatin, carboplatin, oxaliplatin, plus oxalipalladium were loaded and investigated for release. Based on loading analysis, the loading ability of the mentioned metallodrug on N-HMSNs was dependent on the nature of the drug structure as well as hydrophobic or hydrophilic interactions. Different adsorption and release profiles were observed for all mentioned compounds via dialysis and ICP method analysis. Although the maximum to minimum loading occurred for oxalipalladium, cisplatin, and oxaliplatin to carboplatin, respectively, release from a surface with greater control belonged to carboplatin to cisplatin systems in the absence and presence of HSA to 48 hours due to weak interaction for carboplatin drug. The quick release of all mentioned compounds from the protein level at high doses of the drug during chemotherapy occurred very fast within the first 6 hours. In addition, the cytotoxic activity of both free drugs and drug-loaded@N-HMSNs samples on cancerous MCF-7, HCT116, A549, and normal HFF cell lines was evaluated by MTT assay. It was found that free metallodrugs exhibited more active cytotoxic behavior on both cancerous and normal cell lines than drug-loaded@N-HMSNs. Data demonstrated that the Cisplatin@N-HMSNs with SI=6.0 and 6.6 for MCF7 and HCT116 cell lines, respectively, and Oxaliplatin@N-HMSNs with SI=7.4 for HCT116 cell line can be good candidates as an anticancer drug with minimal side effects by protecting cytotoxic drugs as well as controlled release and high selectivity.
... One method is the fabrication of hierarchical materials which combine micro-and mesoporosity. [154][155][156] Several synthetic approaches have been suggested, with the following two being the most attractive: (i) the formation of zeolite seeds and subsequent self-assembly into a mesoporous framework and (ii) the production of mesopores in zeolites by primary or post-fabrication methods. Approaches to self-assembly have also shown the ability to create unique structures. ...
Bioethanol, synthesized through the valorization of biomass resources, is of great importance to many industries. As bioethanol has become more abundant and its price has decreased, it has become an attractive candidate for application as a base material for the synthesis of a variety of petrochemicals and fuel through catalysis. In this article, a comprehensive review of the catalytic conversion of bioethanol into hydrocarbons, including olefins and gasoline, is presented. In addition, developments and potential research opportunities in the field of bioethanol catalysis are provided to enhance bioethanol conversion. According to the findings of the study, despite significant progress in bioethanol conversion, further research is needed to address several challenges that will enable improved biofuel and chemical production. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).
... Zeolites are aluminosilicate minerals with exceptional adsorption characteristics that Na + , K + , Ca 2+ , Mg 2+ , and Al 3+ are found in them (Srikanth et al., 2017). Zeolite structures are particularly interesting supports with considerable benefits for specific immobilization approaches as well as for recycling and reuse operations due to their high porosity, mechanical (Diban et al., 2021;Angela et al., 2022), and photo-chemical stability, homogeneous pore distribution in both the channel and cages and activity under UV visible irradiation over 240 nm wavelength (Adnan et al., 2018). ...
... The conversion and specificity of zeolite in numerous catalytic reactions have been broadly explored over the past few decades, and it can be inferred that this type of porous materials is a very promising candidate because of its lengthy catalytic lifecycle and good selectivity toward reactants [45][46][47][48]. Despite these outstanding findings, coke production is made simple and the effectiveness of commercial catalysts is constrained by the micropores in zeolite, that affect the reactants and products mass transfer from active sites (locates) [49,50]. ...
In this work, post-synthetic effective acid (HNO 3 ) and base (NaOH) etching technique are used to create hierarchical mordenite having different pore structure. The powder X-ray diffraction (P-XRD) technique was used to confirm the crystalline structure of the base modified and acid modified mordenite. Field emission-Scanning electron microscope (FE-SEM) was employed to confirm the structural morphology of the materials. The modified mordenite were further characterized by Inductive coupled plasma-optical emission spectrometry (ICP-OES), N 2 adsorption-desorption isotherms, thermogravimetric analysis (TGA), acid base titration, to confirm the structural integrity, presence of active acidic sites, and other vital parameters. The structure was well conserved after the change, as evidenced by the characterization. The toluene alkylation with benzyl alcohol using hierarchical Mordenite and H-Mordenite produced mono-benzylated toluene. Comparison between acid treated, base treated and H-Mordenite was done. All samples were catalytically active as proved by the catalytic result in the alkylation reaction. The results show that the base alteration dramatically enhances the mesoporous surface area of H-Mordenite. Furthermore, the acid treated Mordenite had the highest benzyl alcohol conversion (75%), but the base modified Mordenite had benzyl alcohol conversion of 73% with the highest mono-benzylated toluene selectivity (61%). The process was further optimised by varying the reaction temperature, duration, and catalyst quantity. Gas Chromatography (GC) was used to evaluate the reaction products and gas chromatography-mass spectrometry (GC-MS) was used to confirm them. Introduction of mesoporosity in the microporous Mordenite was found to have significant effect on their catalytic activity.
... It is not allowed to populate (O, N, S) hybrid atoms in pentagonal or hexagonal cyclic compounds Or, these rings may be compensated with acidic or basic groups in different locations, and if these groups are present in an ortho position relative to the azo bridge group, it will give another site of coordination, as the coordination of the far nitrogen atom in the bridge azo group with the metal ion and the donating atom in the ortho site in the rings Aromatics will be pentagonal rings with high stability. The chemical and physical properties of these compounds vary depending on the change of heterogeneous rings, which leads to a change in the basic and acidic properties and their solubility in polar and non-polar solvents (9,10) . Imidazole is a white crystalline solid solid in the same mold with a high solubility in water. ...
... Due to (C8H8O) + , another fragmentat (m/z*=120) exists. The mass spectrum and fragmentation pattern of the azo-Schiff ligand are shown in Figure 6 and Scheme 3. Figure 1 displays the mass spectra of the azo ligand (DPIMB) (9). The M+ peak, which corresponds to a chemical formula (C23H18N4O2), the calculated formula weight is (382).The base peak was observed at (m/z 335) corresponding to (C23H18N) + Another fragments at (m/z 218 and 135) due to 4,5-di phenyl imidazole (C16H12N) + and (C8H7O2) + . ...
... Medicatio are delivered via the SBA-15, SBA-16, MCM-41, and MCM-48 which are all commo utilized [16]. [17], published by MDPI, 20 [18], published by MDPI, 2022, [19], published by MDPI, 2013, [20], published by MDPI, 2020 Figure 2. Types of mesoporous silica nanoparticles. Adapted from [17], published by MDPI, 2010, [18], published by MDPI, 2022, [19], published by MDPI, 2013, [20], published by MDPI, 2020. ...
... [17], published by MDPI, 20 [18], published by MDPI, 2022, [19], published by MDPI, 2013, [20], published by MDPI, 2020 Figure 2. Types of mesoporous silica nanoparticles. Adapted from [17], published by MDPI, 2010, [18], published by MDPI, 2022, [19], published by MDPI, 2013, [20], published by MDPI, 2020. MSNs have quite good physicochemical properties and are tunable. ...
... The rate of hydrolysis, the interaction between a constructed template and silica polymer, and condensation of the silica source are all variables that impact the size and form of mesoporous silica nanoparticles. By changing the pH, we can regulate the above variables using various templates and co-solvents [18]. Biological variables such as blood circulation time, in vivo distribution, and excretion rate can be influenced by particle size [15]. ...
Citation: Sreeharsha, N.; Philip, M.; Krishna, S.S.; Viswanad, V.; Sahu, R.K.; Shiroorkar, P.N.; Aasif, A.H.; Fattepur, S.; Asdaq, S.M.B.; Nair, A.B.; et al. Multifunctional Mesoporous Silica Nanoparticles for Oral Drug Delivery. Coatings 2022, 12, 358.
