Abstract:L-Cysteine-modified dendritic fibrous nanosilica grafted by amine groups (Cys-DFNS-NH 2 ) have been synthesized by a novel hydrothermal method. The N2 adsorption-desorption isotherms analysis on the Cys-DFNS-NH 2 show that the average pore volume and surface area of the prepared fibrous Cys-DFNS-NH 2 were 2.2 cm 3 /g and 205 m 2 /g, respectively, while the average pore size is 6.06 nm. Adsorption behavior of the Cys-DFNS-NH 2 for Cd 2þ , Cu 2þ , Ag þ , and Pb 2þ was investigated by electrochemical methods. The… Show more
“…Then 50 μL 3-aminopropyltriethoxysilane (APTES) was added to the mixture and refluxed for 20 h at 80 °C. Then the mixture was separated and washed with toluene several times and dried at 80 °C for at least 24 h 63 .…”
Fibrous nano-silica sphere (KCC-1) has appeared as a good and efficient catalyst for ultrasonic irradiation conditions in chemical reactions. This catalyst has the unique properties such as a fibrous surface morphology, high surface area and high mechanical stability. The results indicated that the KCC-1 nanocatalyst could be used as high-performance catalysts under high temperature and pressure condition in organic reaction under ultrasonic irradiation. Morphology, structure, and composition of the fibrous nano-silica sphere were described by N2 adsorption–desorption analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FT-IR). In this work, we used KCC-1@NH2 nanosilica as a basic catalyst for the preparation of chromenes under ultrasonic irradiation conditions for the first time. The recyclability, nontoxicity and high stability of the catalyst, combined with low reaction times and excellent yields, make the present protocol very useful for the synthesis of the title products under ultrasonic conditions. The produced products were confirmed via 1H NMR, 13C NMR, FT-IR analysis.
“…Then 50 μL 3-aminopropyltriethoxysilane (APTES) was added to the mixture and refluxed for 20 h at 80 °C. Then the mixture was separated and washed with toluene several times and dried at 80 °C for at least 24 h 63 .…”
Fibrous nano-silica sphere (KCC-1) has appeared as a good and efficient catalyst for ultrasonic irradiation conditions in chemical reactions. This catalyst has the unique properties such as a fibrous surface morphology, high surface area and high mechanical stability. The results indicated that the KCC-1 nanocatalyst could be used as high-performance catalysts under high temperature and pressure condition in organic reaction under ultrasonic irradiation. Morphology, structure, and composition of the fibrous nano-silica sphere were described by N2 adsorption–desorption analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FT-IR). In this work, we used KCC-1@NH2 nanosilica as a basic catalyst for the preparation of chromenes under ultrasonic irradiation conditions for the first time. The recyclability, nontoxicity and high stability of the catalyst, combined with low reaction times and excellent yields, make the present protocol very useful for the synthesis of the title products under ultrasonic conditions. The produced products were confirmed via 1H NMR, 13C NMR, FT-IR analysis.
“…Also, after surface functionalization, there was no noticeable change in the fibrous and spherical structure of the KCC-1, and the structure remains intact. It is reported that the existence of nanoporous silica fibers in the structure of KCC-1 efficiently renders molecular accessibility to the surface of KCC-1 in comparison to other types of mesoporous silica materials which makes KCC-1 as an attractive candidate for drug delivery and controlled release applications 49 , 87 , 88 . Figure 2 TEM images of ( a ) KCC-1 and ( b ) KCC-1-NH 2 particles.…”
In the pharmaceutical manufacturing, drug release behavior development is remained as one of the main challenges to improve the drug effectiveness. Recently, more focus has been done on using mesoporous silica materials as drug carriers for prolonged and superior control of drug release in human body. In this study, release behavior of paracetamol is developed using drug-loaded KCC-1-NH2 mesoporous silica, based on direct compaction method for preparation of tablets. The purpose of this study is to investigate the utilizing of pure KCC-1 mesoporous silica (KCC-1) and amino functionalized KCC-1 (KCC-1-NH2) as drug carriers in oral solid dosage formulations compared to common excipient, microcrystalline cellulose (MCC), to improve the control of drug release rate by manipulating surface chemistry of the carrier. Different formulations of KCC-1 and KCC-NH2 are designed to investigate the effect of functionalized mesoporous silica as carrier on drug controlled-release rate. The results displayed the remarkable effect of KCC-1-NH2 on drug controlled-release in comparison with the formulation containing pure KCC-1 and formulation including MCC as reference materials. The pure KCC-1 and KCC-1-NH2 are characterized using different evaluation methods such as FTIR, SEM, TEM and N2 adsorption analysis.
“…The large surface area of the DFNS promotes more active sites for grafting functional groups with excellent chemical, mechanical, and thermal stability [30] . These features have made it an ideal candidate as a support material for many organic amine moieties, [31] organometallic complexes, [32] organic molecules, [33] metals, [34] metal oxides, [35] peptides, [36] polymers, [37] proteins, [38] enzymes, [39] etc. Therefore, DFNS ‐based materials have broad applications in drug delivery, gas capture, energy storage, biosensing, molecular probes, affinity ligands, and various adsorbents [36,40] .…”
Cycloaddition of CO2 with epoxide to form cyclic carbonate is one of the most promising approaches to mitigate the rising level of CO2 in the atmosphere. Therefore, the design and synthesis of new materials which can efficiently catalyze such reactions has become an important research area. This article reports on the synthesis of a new material, adenine functionalized dendritic fibrous nanosilica (DAD), by functionalizing the surface of dendritic fibrous nanosilica (DFNS) with an N‐containing heterocyclic nucleobase adenine using a bifunctional isocyanate crosslinker ((EtO)3Si(CH2)3NCO). The surface amine functionalities enable DAD to show selective CO2 adsorption (0.44 mmol/g, at 1 bar CO2 pressure and 298 K temperature) due to acid‐base interaction between CO2 and amine groups. Moreover, DAD efficiently catalyzes the fixation of CO2 with a variety of epoxides into corresponding cyclic carbonates in the presence of TBAB (tetrabutylammonium bromide) co‐catalyst under solvent‐free conditions. The DFNS skeleton of DAD offers a high surface area for enhanced CO2 adsorption, while its organic surface groups, adenine and carbamide, boost the selectivity and activate the epoxide ring and CO2 for cycloaddition reaction. The strong covalent linkage of surface groups in DAD renders robust structural integrity, enabling the catalyst to be recycled multiple times with negligible reduction in its catalytic performance.
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