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1.
Maryam Nourian Farnaz Zadehahmadi Reihaneh Kardanpour Shahram Tangestaninejad Majid Moghadam Valiollah Mirkhani Iraj Mohammadpoor‐Baltork 《应用有机金属化学》2018,32(1)
The catalytic activity of magnetically recoverable MIL‐101 was investigated in the oxidation of alkenes to carboxylic acids and cyanosilylation of aldehydes. MIL‐101 was treated with Fe3O4 and the prepared catalyst was characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, N2 adsorption measurements, field emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy and inductively coupled plasma analysis. The catalytic active sites in this heterogeneous catalyst are Cr3+ nodes of the MIL‐101 framework. This heterogeneous catalyst has the advantages of excellent yields, short reaction times and reusability several times without significant decrease in its initial activity and stability in both oxidation and cyanosilylation reactions. Its magnetic property allows its easy separation using an external magnetic field. 相似文献
2.
Incorporating Polyoxometalates into a Porous MOF Greatly Improves Its Selective Adsorption of Cationic Dyes 下载免费PDF全文
Ai‐Xue Yan Dr. Shuang Yao Prof. Yang‐Guang Li Dr. Zhi‐Ming Zhang Dr. Ying Lu Dr. Wei‐Lin Chen Prof. En‐Bo Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(23):6927-6933
Various polyoxometalates (POMs) were successfully immobilized to the mesoporous coordination polymer MIL‐101 resulting in a series of POM–MOF composite materials POM@MIL‐101 (POM=K4PW11VO40, H3PW12O40, K4SiW12O40). These materials were synthesized by a simple one‐pot reaction of Keggin POMs, tetramethylammonium hydroxide (TMAH), terephthalic acid (H2bdc), and Cr3+ ions. XRD, FTIR, thermogravimetric analyses (TG), inductively coupled plasma (ICP) spectrometry, and energy‐dispersive X‐ray spectroscopy (EDX) collectively confirmed the successful combination of POMs and the porous framework. Further, these composites POM@MIL‐101 with different loading of POMs were achieved by variation of the POM dosage. Notably, the uptake capacity of MIL‐101 towards organic pollutants in aqueous solution was significantly improved by immobilization of hydrophilic POMs into cages of MIL‐101. An uptake capacity of 371 mg g?1, comparable to that of the graphene oxide sponges, and much higher than that of the commercial activated carbon, was achieved at room temperature in 5 min when dipping 20 mg PW11V@MIL‐101 in the methylene blue (MB) solution (100 mL of 100 mg L?1 MB solution). Further study revealed that the POM@MIL‐101 composite materials not only exhibited a fast adsorption rate towards dye molecules, but also possessed of selective adsorption ability of the cationic dyes in wastewater. For example, the adsorption efficiency of PW11V@MIL‐101 (10 mg) towards MB (100 mL of 10 mg L?1) could reach 98 % in the initial 5 min, and it could capture MB dye molecules from the binary mixture of the MB and MO with similar size. Also, the POM@MIL‐101 materials could be readily recycled and reused, and no POM leached in the dye adsorption process. 相似文献
3.
A series of Keggin‐type heteropolyacid‐based heterogeneous catalysts (Co‐/Fe‐/Cu‐POM‐octyl‐NH3‐SBA‐15) were synthesized via immobilized transition metal mono‐ substituted phosphotungstic acids (Co‐/Fe‐/Cu‐POM) on octyl‐amino‐co‐functionalized mesoporous silica SBA‐15 (octyl‐NH2‐SBA‐15). Characterization results indicated that Co‐/Fe‐/Cu‐POM units were highly dispersed in mesochannels of SBA‐15, and both types of Brønsted and Lewis acid sites existed in Co‐/Fe‐/Cu‐POM‐octyl‐NH3‐SBA‐15 catalysts. Co‐POM‐octyl‐NH3‐SBA‐15 catalyst showed excellent catalytic performance in H2O2‐mediated cyclohexene epoxidation with 83.8% of cyclohexene conversion, 92.8% of cyclohexene oxide selectivity, and 98/2 of epoxidation/allylic oxidation selectivity. The order of catalytic activity was Co‐POM‐octyl‐NH3‐SBA‐15 > Fe‐POM‐octyl‐NH3‐SBA‐15 > Cu‐POM‐octyl‐NH3‐SBA‐15. In order to obtain insights into the role of ‐octyl moieties during catalysis, an octyl‐free catalyst (Co‐POM‐NH3‐SBA‐15) was also synthesized. In comparison with Co‐POM‐NH3‐SBA‐15, Co‐POM‐octyl‐NH3‐SBA‐15 showed enhanced catalytic properties (viz. activity and selectivity) in cyclohexene epoxidation. Strong chemical bonding between ‐NH3+ anchored on the surface of SBA‐15 and heteropolyanions resulted in excellent stability of Co‐POM‐octyl‐NH3‐SBA‐15 catalyst, and it could be reused six times without considerable loss of activity. 相似文献
4.
A Polyoxometalate‐Encapsulating Cationic Metal–Organic Framework as a Heterogeneous Catalyst for Desulfurization 下载免费PDF全文
Dr. Xiu‐Li Hao Yuan‐Yuan Ma Prof. Hong‐Ying Zang Dr. Yong‐Hui Wang Prof. Yang‐Guang Li Prof. En‐Bo Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(9):3778-3784
A new cationic triazole‐based metal–organic framework encapsulating Keggin‐type polyoxometalates, with the molecular formula [Co(BBPTZ)3][HPMo12O40]?24 H2O [compound 1 ; BBPTZ=4,4′‐bis(1,2,4‐triazol‐1‐ylmethyl)biphenyl] is hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, powder X‐ray diffraction, and single‐crystal X‐ray diffraction. The structure of compound 1 contains a non‐interpenetrated 3D CdSO4 (cds)‐type framework with two types of channels that are interconnected with each other; straight channels that are occupied by the Keggin‐type POM anions, and wavelike channels that contain lattice water molecules. The catalytic activity of compound 1 in the oxidative desulfurization reaction indicates that it is not only an effective and size‐selective heterogeneous catalyst, but it also exhibits distinct structural stability in the catalytic reaction system. 相似文献
5.
《应用有机金属化学》2017,31(10)
A heterogeneous material composed of MCM‐48/H5PW10V2O40 was produced and used as an efficient, eco‐friendly and highly recyclable catalyst for the one‐pot and multicomponent synthesis of 3,4‐dihydroquinoxalin‐2‐amine, diazepine‐tetrazole and benzodiazepine‐2‐carboxamide derivatives in aqueous media and at room temperature with high yields in short reaction times (40–60 min). The recoverable catalyst was easily recycled at least five times without any loss of catalytic activity. The structures of obtained products were confirmed using 1H NMR and 13C NMR spectra. 相似文献
6.
One‐pot synthesis of 1‐ and 5‐substituted 1H‐tetrazoles using 1,4‐dihydroxyanthraquinone–copper(II) supported on superparamagnetic Fe3O4@SiO2 magnetic porous nanospheres as a recyclable catalyst 下载免费PDF全文
An effective one‐pot, convenient process for the synthesis of 1‐ and 5‐substituted 1H‐tetrazoles from nitriles and amines is described using1,4‐dihydroxyanthraquinone–copper(II) supported on Fe3O4@SiO2 magnetic porous nanospheres as a novel recyclable catalyst. The application of this catalyst allows the synthesis of a variety of tetrazoles in good to excellent yields. The preparation of the magnetic nanocatalyst with core–shell structure is presented by using nano‐Fe3O4 as the core, tetraethoxysilane as the silica source and poly(vinyl alcohol) as the surfactant, and then Fe3O4@SiO2 was coated with 1,4‐dihydroxyanthraquinone–copper(II) nanoparticles. The new catalyst was characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, dynamic light scattering, thermogravimetric analysis, vibration sample magnetometry, X‐ray photoelectron spectroscopy, nitrogen adsorption–desorption isotherm analysis and inductively coupled plasma analysis. This new procedure offers several advantages such as short reaction times, excellent yields, operational simplicity, practicability and applicability to various substrates and absence of any tedious workup or purification. In addition, the excellent catalytic performance, thermal stability and separation of the catalyst make it a good heterogeneous system and a useful alternative to other heterogeneous catalysts. Also, the catalyst could be magnetically separated and reused six times without significant loss of catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
7.
Dr. Nuo‐Wei Zhang Prof. Chuan‐Jing Huang Xiao‐Quan Zhu Jing‐Dong Xu Prof. Wei‐Zheng Weng Prof. Hui‐Lin Wan 《化学:亚洲杂志》2012,7(8):1895-1901
The effects of calcination temperature and feedstock pretreatment on the catalytic performance of Co/γ‐Al2O3 catalysts were studied for partial oxidation of methane (POM) to synthesis gas, with emphasis on the role of feedstock pretreatment. The physicochemical properties of the catalysts were characterized by N2 adsorption, X‐ray diffraction (XRD), transmission electron microscopy (TEM), H2 temperature‐programmed reduction (H2‐TPR), and Raman spectroscopy. The results showed that the pretreatment of the catalyst by reaction gas significantly improved the catalytic activity and stability for the POM reaction. On the other hand, the effect of calcination temperature was less significant. Although the initial activity was increased by an increased calcination temperature, the catalyst without the feedstock pretreatment suffered a rapid deactivation. The reaction‐atmosphere pretreatment was revealed as a process that mainly modified the surface structure of the catalyst. In that process, the formation of a CoAl2O4‐like compound led to high Co metal dispersion after reduction, and the transformation of the carrier into α‐Al2O3 occurred over the catalyst surface. Both the high dispersion of cobalt and the presence of α‐Al2O3 surface phase were assumed as the important factors resulting in an excellent catalytic performance in terms of high activity and high stability. 相似文献
8.
《应用有机金属化学》2017,31(11)
We report the synthesis of ionic liquid‐functionalized mesoporous silica nanoparticles ([pmim]FeCl4/MSNs) via a method of post‐grafting on parent MSNs. This hybrid material was characterized using scanning and transmission electron microscopies, energy‐dispersive X‐ray spectroscopy, nitrogen adsorption–desorption analysis, Fourier transform infrared spectroscopy, powder X‐ray diffraction and thermal analyses. The material was utilized as an efficient heterogeneous catalyst for the synthesis of N ,N ′‐diaryl‐substituted formamidines through the reaction of triethyl orthoformate with arylamines under solvent‐free conditions. The catalyst was recovered easily and reused several times without significant loss of its catalytic activity. 相似文献
9.
Vlad Pascanu Dr. Qingxia Yao Dr. Antonio Bermejo Gómez Dr. Mikaela Gustafsson Yifeng Yun Dr. Wei Wan Dr. Louise Samain Prof. Xiaodong Zou Prof. Belén Martín‐Matute 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(51):17483-17493
Palladium nanoparticles have been immobilized into an amino‐functionalized metal–organic framework (MOF), MIL‐101Cr‐NH2, to form Pd@MIL‐101Cr‐NH2. Four materials with different loadings of palladium have been prepared (denoted as 4‐, 8‐, 12‐, and 16 wt %Pd@MIL‐101Cr‐NH2). The effects of catalyst loading and the size and distribution of the Pd nanoparticles on the catalytic performance have been studied. The catalysts were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier‐transform infrared (FTIR) spectroscopy, powder X‐ray diffraction (PXRD), N2‐sorption isotherms, elemental analysis, and thermogravimetric analysis (TGA). To better characterize the palladium nanoparticles and their distribution in MIL‐101Cr‐NH2, electron tomography was employed to reconstruct the 3D volume of 8 wt %Pd@MIL‐101Cr‐NH2 particles. The pair distribution functions (PDFs) of the samples were extracted from total scattering experiments using high‐energy X‐rays (60 keV). The catalytic activity of the four MOF materials with different loadings of palladium nanoparticles was studied in the Suzuki–Miyaura cross‐coupling reaction. The best catalytic performance was obtained with the MOF that contained 8 wt % palladium nanoparticles. The metallic palladium nanoparticles were homogeneously distributed, with an average size of 2.6 nm. Excellent yields were obtained for a wide scope of substrates under remarkably mild conditions (water, aerobic conditions, room temperature, catalyst loading as low as 0.15 mol %). The material can be recycled at least 10 times without alteration of its catalytic properties. 相似文献
10.
Sulfonated palladium(II) N‐heterocyclic carbene complex immobilized on nano–micro size poly(4‐vinylpyridinium chloride) for Suzuki‐Miyaura cross‐coupling reaction 下载免费PDF全文
Zari Pahlevanneshan Majid Moghadam Valiollah Mirkhani Shahram Tangestaninejad Iraj Mohammadpoor‐Baltork Saghar Rezaei 《应用有机金属化学》2015,29(10):678-682
The sulfonated palladium(II) N‐heterocyclic carbene complex PdII(NHC)SO3?, supported on poly(4‐vinylpyridinium chloride), was used as a heterogeneous, recyclable and active catalyst for the Suzuki–Miyaura reaction. This catalyst was applied for coupling of various aryl halides with phenylboronic acid and the corresponding products were obtained in excellent yields and short reaction times. The catalyst was characterized using Fourier transform infrared and diffuse reflectance UV–visible spectroscopies, scanning electron microscopy and elemental analysis. After each reaction, the catalyst was recovered easily by simple filtration and reused several times without significant loss of its catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献