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31.
Tungstate ions were successfully loaded onto triazine‐based ionic liquid‐functionalized magnetic nanoparticles through an anion exchange process. The use of triazine core for creating ionic liquid led to the immobilization of high amounts of WO42?. The resulting catalyst showed high activity and selectivity in the oxidation of sulfides to sulfoxides with H2O2 as a green oxidant at room temperature. In addition, due to the presence of ammonium groups in the catalyst structure, water dispersibility of the catalyst was increased. More important, the catalyst was magnetically recovered and reused for up to six runs without any marked decrease of activity and selectivity. Finally, easy gram‐scale oxidation of methylphenyl sulfide as well as fast separation of catalyst and product makes the protocol economical and industrially applicable. 相似文献
32.
Sahra Balilehvand Seyed Majid Hashemianzadeh SeyedehSaleheh Razavi Hedayat Karimi 《Adsorption》2012,18(1):13-22
A combination of ab initio quantum mechanical (QM) calculations and canonical Monte Carlo (CMC) simulations are employed to
investigate possible usage of single-walled silicon nanotubes (SWSiNTs) as a novel media for hydrogen and methane adsorption
as well as their separation from each other. By fitting the force field, a Morse potential model is selected as an efficient
potential to describe the binding energies between both hydrogen-SiNTs and methane-SiNTs obtained from ab initio calculations.
Then CMC simulations are performed to evaluate the adsorption and separation behaviors of H2 and CH4 on the three different sizes of SiNTs including (5, 5), (7, 7), and (9, 9) SiNTs at ambient temperatures and pressures from
1 up to 10 MPa. As a comparison, the adsorption and separation of H2 and CH4 on the (8, 8) CNTs which are isodiameter with (5, 5) SiNTs are also simulated. Results are indicative of remarkable enhancement
of H2 and CH4 adsorption capacity on the SiNTs compared to the CNTs, which arise from stronger van der Waals (VDW) attractions. In the
case of methane adsorption on SiNTs, the stored volumetric energy exceeds the goal of the US Freedom CAR Partnership by 2010,
which can not be achieved by methane compression at such low pressures. Moreover, simulation results indicate that SiNTs preferentially
adsorb methane relative to hydrogen in their equimolar mixture, which results in efficient separation of these gases from
each other at 293 K. 相似文献
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A heterogeneous magnetic copper catalyst was prepared via anchoring of copper sulfate onto multi‐layered poly(2‐dimethylaminoethyl acrylamide)‐coated magnetic nanoparticles and was characterized using various techniques. The catalyst was found to be active, effective and selective for one‐pot three‐component reaction of alkyl halide, sodium azide and alkyne, known as copper‐catalyzed click synthesis of 1,2,3‐triazoles. As little as 0.3 mol% of catalyst was found to be effective under the optimum conditions. The catalyst could also be recycled and reused up to seven times without significant loss of activity. Thermal stability, high loading level of copper on catalyst, broad diversity of alkyl/benzyl/allyl bromide/chloride and alkyl/aryl terminal alkynes without isolation of azide intermediate, and good to excellent yields of products make this procedure highly economical. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Benvidi Ali Tezerjani Marzieh Dehghan Moshtaghiun Seyed Mohammad Mazloum-Ardakani Mohammad 《Mikrochimica acta》2016,183(5):1797-1804
Microchimica Acta - The authors describe an aptasensor for tetracycline (TET) based on the use of a glassy carbon electrode (GCE) modified with graphene oxide nanosheets. The latter were placed on... 相似文献
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Arefeh Dadras M. Reza Naimi‐Jamal Firouz Matloubi Moghaddam Seyed Ebrahim Ayati 《应用有机金属化学》2018,32(2)
Aryl halides and especially inactive aryl chlorides were coupled to benzenoid aromatic rings in a Suzuki–Miyaura coupling reaction in the absence of organic solvents and toxic phosphine ligands. The reaction was catalysed by a recoverable magnetic nanocatalyst, Pd@Fe3O4, in aqueous media. This method is green, and the catalyst is easily removed from the reaction media using an external magnetic field and can be re‐used at least 10 times without any considerable loss in its activity. The catalyst was characterized using scanning and transmission electron microscopies, thermogravimetric analysis, inductively coupled plasma spectroscopy, Fourier transform infrared spectroscopy, CHN analysis, X‐ray diffraction and vibrating sample magnetometry. 相似文献