排序方式: 共有48条查询结果,搜索用时 15 毫秒
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Mohammad Ali Ghasemzadeh Javad Safaei-Ghomi Halimeh Molaei 《Comptes Rendus Chimie》2012,15(11-12):969-974
An efficient and environmentally friendly method for the one-pot synthesis of 1,8-dioxo-decahydroacridines has been developed in the presence of Fe3O4 nanoparticles. The multicomponent reactions of aldehydes, dimedone and amines were carried out under solvent-free conditions to obtain some 1,8-dioxo-9-aryl-10-aryl-decahydroacridine derivatives. The present approach provides several advantages including high yields, short reaction times, little catalyst loading and facile catalyst separation. 相似文献
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Magnetic molecularly imprinted composite for the selective solid‐phase extraction of p‐aminosalicylic acid followed by high‐performance liquid chromatography with ultraviolet detection 下载免费PDF全文
Hasan Bagheri Karam Molaei Ali Akbar Asgharinezhad Homeira Ebrahimzadeh Mojtaba Shamsipur 《Journal of separation science》2016,39(21):4166-4174
A new method for the selective extraction of p‐aminosalicylic acid from aqueous and urine samples has been developed using magnetic molecularly imprinted polymer nanoparticles before determination by high‐performance liquid chromatography. The Fe3O4 nanoparticles were first prepared through the chemical coprecipitation of Fe2+ and Fe3+ and then coated with a vinyl shell. Subsequently, a layer of molecularly imprinted polymers was grafted onto the vinyl‐modified magnetic nanoparticles by precipitation polymerization. FTIR spectroscopy, scanning electron microscopy, vibrating sample magnetometry, and thermogravimetric analysis were applied to characterize the sorbent properties. Moreover, the predominant parameters affecting the magnetic solid phase extraction such as sample pH, sorption and elution times, the amount of sorbent, and composition and volume of eluent were investigated thoroughly. The maximum sorption capacity of the imprinted polymer toward p‐aminosalicylic acid was 70.9 mg/g, which is 4.5 times higher than that of the magnetic nonimprinted polymer. The magnetic molecularly imprinted polymer nanoparticles were applied for the selective extraction of p‐aminosalicylic acid from aqueous and urine samples and satisfactory results were achieved. The results illustrate that magnetic molecularly imprinted polymer nanoparticles have a great potential in the extraction of p‐aminosalicylic acid from environmental and biological matrices. 相似文献
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Jalilian Niloofar Ebrahimzadeh Homeira Asgharinezhad Ali Akbar Molaei Karam 《Mikrochimica acta》2017,184(7):2191-2200
Microchimica Acta - The authors describe the synthesis of a nanosorbent for fast magnetic solid phase extraction of trace levels of Ag(I), Au(III), Pd(II) and Pt(II). It consists of graphene oxide... 相似文献
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Samira Sabagh Mohammad Izadyar Foroogh Arkan 《International journal of quantum chemistry》2020,120(10):e26171
The molecular modification and the effects of the gas and water media on the ability of some flavonoids as the photosensitizers in the natural dye-sensitized solar cells were theoretically investigated. According to the results, water increases the electrophilicity of the dyes and weakens the dye/TiO2 coupling, prohibiting the electron injection toward TiO2. A longer path for charge transfer and a less electron-hole overlap for dihydroxychromens elevate the electron transfer more efficient than trihydroxychromen-based flavonoids. However, the presence of water molecules within an increment in the OH groups in the flavonoid structures improves their spectroscopic properties, which is related to decrement in the gap of the frontier molecular orbitals and increment in the oscillator strength. Also, such favorable structural effects and influence of the water medium on the polarizability and excited-state lifetime have emerged. According to the energy conversion efficiency, water is a favorable solvent for dihydroxychromen-based flavonoids. Finally, different analyses on the structural geometries, excited-state, lifetime within the kinetics, and dynamics of the photovoltaic processes were performed and discussed. 相似文献
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Gas chromatographic detection of some nitro explosive compounds in soil samples after solid‐phase microextraction with carbon ceramic copper nanoparticle fibers 下载免费PDF全文
Khalil Farhadi Shayesteh Bochani Mehdi Hatami Rahim Molaei Hossein Pirkharrati 《Journal of separation science》2014,37(13):1578-1584
In this research, a new solid‐phase microextraction fiber based on carbon ceramic composites with copper nanoparticles followed by gas chromatography with flame ionization detection was applied for the extraction and determination of some nitro explosive compounds in soil samples. The proposed method provides an overview of trends related to synthesis of solid‐phase microextraction sorbents and their applications in preconcentration and determination of nitro explosives. The sorbents were prepared by mixing of copper nanoparticles with a ceramic composite produced by mixture of methyltrimethoxysilane, graphite, methanol, and hydrochloric acid. The prepared sorbents were coated on copper wires by dip‐coating method. The prepared nanocomposites were evaluated statistically and provided better limits of detection than the pure carbon ceramic. The limit of detection of the proposed method was 0.6 μg/g with a linear response over the concentration range of 2–160 μg/g and square of correlation coefficient >0.992. The new proposed fiber has been demonstrated to be a suitable, inexpensive, and sensitive candidate for extraction of nitro explosive compounds in contaminated soil samples. The constructed fiber can be used more than 100 times without the need for surface generation. 相似文献
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N-Arylation of a wide variety of amines with phenylboronic acid catalyzed by copper acetate under 20%aqueous solution of n-Bu4NOH was accomplished in good to excellent yields(up to 92%) and substrate conversions(up to 96%). 相似文献