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101.
CuO‐CeO2 nanocomposite is reported as a highly efficient and recyclable catalyst for the green synthesis of 1,8‐dioxooctahydroxanthenes in water. This catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any losing of its efficiency.  相似文献   
102.
103.
We report here two simple methods for the synthesis of benzo[c]acridine derivatives from three-component, one-pot condensation of 1-naphthylamine, dimedone, and a variety of substituted aldehydes in the presence of a catalytic amount of NH2SO3H or H6P2W18O62 · 18H2O under solvent-free conditions at 120 °C or in refluxing ethanol.  相似文献   
104.
Reaction of aldehydes and 4-hydroxycoumarin in the presence of catalytic amount of silica-supported Preyssler nanoparticles led to synthesis of bis-coumarins in excellent yields.  相似文献   
105.
1,1‐Diacetates have been synthesized by the reaction of a variety of aldehydes with acetic anhydride in the presence of cupric nitrate as catalyst under solvent‐free conditions. Ketones were not converted to the corresponding diacetates under these conditions.  相似文献   
106.
The sodium salts of the conjugated bases of uracils undergo highly chemoselective O4-monoalkylation when treated with various alkyl halides in dry DMF, while the use of methyl iodide results in N1+N3-dimethylation. Theoretical evaluations of the chemo- and regioselectivity along with X-ray crystallographic data are presented.  相似文献   
107.
Erbium-165 with 10.3 h physical half-life decays completely by electron capture to the ground state of stable isotope 165Ho and it is an ideal radio lanthanide for Auger electron therapy. Excitation function of 165Er via natEr(p,x)165Tm → 165Er, 166Er(p,2n)165Tm → 165Er, 165Ho(p,n)165Er and 165Ho(d,2n)165Er reactions were calculated using ALICE/ASH (Hybrid and GDH models) and EMPIRE 3.1 codes and then were compared with the reported measurement by experimental data and TENDL-2011. Physical yield and target thickness were evaluated with attention to excitation function, stopping power and SRIM code. 165Er was produced using the sedimentation technique through the natEr (p,x)165Tm → 165Er reaction. The deposited target was irradiated with 15 MeV proton beams at 20 μA current for 1 h. The 165Tm production yield was 26 MBq/μA h at the end of bombardment.  相似文献   
108.
A solid phase extraction system for separation and preconcentration of trace amounts of Pb(II), Ni(II), Cd(II) and Cu(II) is proposed. The procedure is based on the adsorption of Pb2+, Ni2+, Cd2+ and Cu2+ ions on a column of 1-(2-pyridylazo)-2-naphthol (PAN) immobilised on surfactant-coated clinoptilolite prior to their determinations by Flame Atomic Absorption Spectroscopy (FAAS). The effective parameters including pH, sample volume, sample flow rate and eluent flow rate were also studied. The analytes collected on the column were eluted with 5 mL of 1 mol L?1 nitric acid. A concentration factor of 180 can be achieved by passing 900 mL of sample through the column. The detection limits (3 s) for Cd, Cu, Pb and Ni were found to be 0.28, 0.12, 0.44 and 0.46 µg L?1, respectively. The relative SDs at 10 µg L?1 (n = 10) for analytes were in the range of 1.2–1.4%. The method was applied to the determination of Pb, Ni, Cd and Cu in water samples.  相似文献   
109.
A novel ozone (O3) sensor is fabricated using commercial metal oxide field effect transistor (MOSFET), modified with single-walled carbon nanotubes (SWCNTs). In this study, integrated circuit (IC: BS250) was selected as the selective probe for O3 detection. For this purpose, a plastic cover on the surface of the drain was drilled to bare the drain surface, followed by its modification with nitrogen and sulfur-functionalized SWCNTs by chemical vapor deposition (CVD) process. The CVD-synthesized SWCNTs were then electrodeposited with FeOOH nanostructures. According to the figures of merit, the fabricated sensor gave a linear output from 20 to 450 parts per billion (ppb). Detection limit was also 4.1?ppb. Relative standard deviation (RSD) for seven replicate analyses was 3.61%. Based on 90% of maximum response (t90), the response time was ~1.5?min. Calibration sensitivity was measured to 1.3?mV/ppb. No interference was observed, when introducing at least 500 folds of interferences of gaseous species such as H2O, HCl, H2S, O2, H2, CO, CO2, NO2, SO2, Cl2, C2H2, CH4 and volatile organic compounds (VOCs) to 250?ppb of O3 solution. Reliability of the sensor was also evaluated via determination of O3 in different air samples.  相似文献   
110.
The Heck coupling of haloarenes with various alkenes was successfully performed in the presence of 0.5 mole % Pd(OAc)2 and 1.0 mole % d-glucosamine as an additive with K2CO3 as the optimal base in a mixture of H2O/iPrOH (φ r = 2: 1) as the reaction solvent at 80°C after 6 h. d-Glucosamine was found to be an inexpensive, air-stable, easy to available, and efficient additive in palladium-catalyzed Heck reactions of aryl iodides (67–95 % conversion) and bromides (38–72 % conversion).  相似文献   
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