Homogenous formation and quaternization of urea-functionalized imidazolyl silane and its immobilization on silica for surface-confined ionic liquid stationary phases
作者:Mingliang Zhang、Jia Chen、Hongdeng Qiu、Abul K. Mallik、Makoto Takafuji、Hirotaka Ihara
DOI:10.1039/c4ra04772a
日期:——
New strategy for surface modification of silica sphere was proposed on the basis of one-pot urea formation and quaternization of imidazole, resulting in sorbents of high tunability and controllable hydrophobicity.
Oxidative Debromination and Degradation of Tetrabromo-bisphenol A by a Functionalized Silica-Supported Iron(III)-tetrakis(p-sulfonatophenyl)porphyrin Catalyst
community. Iron(III)-porphyrin complexes are generally regarded as "green" catalysts and have been reported to catalyze the efficient degradation and dehalogenation of halogenated phenols in environmental wastewaters. However, they are quickly deactivated due to self-degradation in the presence of an oxygen donor, such as KHSO₅. In the present study, an iron(III)-tetrakis (p-sulfonatophenyl)-porphyrin
spectroscopy, solid‐state NMR spectroscopy, X‐ray photoelectron spectroscopy, XRD, TEM, and thermogravimetric analysis. The new Im‐Si‐X‐ϕ materials possess a high surface area, hydrogen‐bond donor ability, and nucleophilicity. The material that contains iodine and is protonated by an inorganic acid shows an excellent catalytic activity for CO2 conversion into cyclic carbonates with good recyclability. Reaction
The imidazole ring is an important chemical component in nature that plays various critical roles. In this study, the imidazole used as a metal-chelating ligand was combined with a silicone resin structure by a long chain. The preparation, surface properties, thermal stability, complexation and adsorption properties with respect to Cu2+ ions, and multiple use cycles of the synthesized organosilicone resin bearing long chain imidazolyl ligands (ImSR) were studied using Fourier transform infrared spectroscopy (FTIR), H-1, C-13 and Si-29 nuclear magnetic resonance (NMR), a contact angle goniometer, thermogravimetric analysis (TGA) and UV-visible spectrophotometry methods. ImSR is a hydrophilic material with a water contact angle of 56 degrees on a flat surface. It possesses good thermal stability and exhibits rapid weight loss above 230 degrees C. ImSR was evaluated as a promising adsorbing material for Cu2+ ions. It exhibited a high affinity for Cu2+ ions, with a maximum adsorption ability of 66.1 mg/g. Langmuir, Freundlich and Dubinin-Radushkevich isotherm models were used to analyze the experimental data. The results showed that the ImSR absorbent exhibited chemisorption and monolayer distribution on homogeneous active sites. The equilibrium adsorption capacity remained relatively constant after 5 use cycles. (C) 2013 Elsevier B.V. All rights reserved.
Imidazole versus pyridine as ligands for metalloporphine immobilization in ligninolytic peroxidases-like biomimetic catalysts
This paper describes the immobilization of 5,10,15,20-tetrakis(2,6-dichlorophenyl)porphine-manganese(III) through coordinative bond onto imidazolyl- and pyridyl-grafted silica, emulating the active site of ligninolytic peroxidases. To this purpose, plain silica gel was functionalized with two organosilanes: the first bearing an imidazolyl functionality, the other one bearing a pyridyl functionality. Manganese-porphine was then immobilized onto the two modified silicas. The two catalytic adducts have been fully characterized to point out the effect of the ligands on their catalytic features. Pyridine-immobilized metalloporphine was found to be a much more performant catalyst, giving significantly higher conversion rates with all the tested substrates: a lignin-model compound such as veratryl alcohol, the lignin peroxidase well-known substrate azure B, and recalcitrant textile dyes such as alizarin red S, phenosafranine, methylene blue, methyl green, xylenol orange, and methyl orange. Imidazole-immobilized metalloporphine on the contrary has proved to be more stable than its pyridine-based counterpart. Besides, the ligands seem to promote different catalytic pathways in the two adducts. These results allow giving rational and rigorous insights about the effect of the ligands during the immobilization of metalloporphines, thus helping in the design of catalysts with specific feature (i.e. stability, reactivity). (C) 2014 Elsevier B.V. All rights reserved.