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951.
Majid M. Heravi Samaheh Sadjadi Hossein A. Oskooie Rahim Hekmat Shoar Fatemeh F. Bamoharram 《中国化学会会志》2008,55(4):890-895
Benzoxazole derivatives were obtained in high yields with excellent purity from the condensation of 2‐aminophenol with benzaldehydes and benzoic acids in the presence of a catalytic amount of heteropolyacids (HPAs). 相似文献
952.
Nona Ghasemi Hamedani Hassan Arabi Gholam Hossein Zohuri Francis S. Mair Andrew Jolleys 《Journal of polymer science. Part A, Polymer chemistry》2013,51(7):1520-1532
The reaction of N‐(4‐(mesitylamino)pent‐3‐en‐2‐ylidene)‐2,4,6‐trimethylbenzenamine ( 1 ) with n‐butyl lithium and then with N‐(2,4,6‐trimethyl‐phenyl)‐acetimidoyl chloride yields a new β‐triketimine ligand, N‐(4‐(mesitylamino)‐3‐(1‐(mesitylimino)ethyl)pent‐3‐en‐2‐ylidene)‐2,4,6‐trimethylbenzenamine, 2 . The addition of 2 to nickel (II) dibromide 1,2‐dimethoxyethane (NiBr2(DME)) in the presence of [Na]+[3,5‐(CF3)4C6H3]4B]? (NaBAr'4) gives a five‐coordinate dimeric complex [( 2 .NiBr)2].2 [(BAr'4)], 3 . The structure of 3 has been determined by single crystal X‐ray diffraction. This complex generates catalytically active species for the homopolymerization of ethylene in combination with methylaluminoxane to produce elastomeric, branched polyethylene. The effect of factors (temperature, pressure, and cocatalyst to catalyst molar ratio (CC)) on the polymerization process has been investigated using regression models of responses (catalyst activity, crystallinity, and weight‐average molecular weight of polymer (Mw)) and visualized via the response surface method (RSM). Activity and Mw responses show a second‐order variation with temperature and vary linearly with pressure. Conversely, crystallinity follows a second‐order model while varying temperature, pressure, and CC. Furthermore, a set of polymerization conditions for reaching desirable responses was predicted and then experimentally verified. The activities achieved challenge the best reported activities for Ni(II) catalysts with β‐connected imine ligand supports, but fall short of those for α‐diimines. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
953.
Majid M. Heravi Ladan Sangsefidi Hossein A. Oskooie Mitra Ghassemzadeh Koroush Tabar-Hydar 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):707-709
Adsorbed on silica gel. Dess-Martin periodinane can rapidly oxidize alcohols to the corresponding carbonyl compounds upon exposure to microwave under solvent-free condition. 相似文献
954.
Ozlem Demirkiran Gülaçtı Topçu Fatemeh Bahadori Mehmet Ay Hossein Nazemiyeh Iqbal Choudhary 《Helvetica chimica acta》2010,93(1):77-83
Two new phenylpropanoid glucosides, 1,2‐erythro‐1‐(3,4,5‐trimethoxyphenyl)‐2‐(β‐D ‐glucopyranosyloxy)propan‐1,3‐diol ( 1 ) and 7,8‐threo‐2′,8‐epoxysyringylglycerol‐7‐O‐α‐D ‐glucopyranoside (ericarboside; 2 ) have been isolated together with four known compounds 2′,7‐epoxysyringylglycerol‐8‐O‐β‐D ‐glucopyranoside (ficuscarpanoside B; 3 ), benzylrutinoside (hydrangeifolin; 4 ), phenethylrutinoside ( 5 ), and caffeic acid from the BuOH soluble part of the MeOH extract of the leaves and flowers of E. arborea L. Final purification of the compounds was achieved on a reversed‐phase HPLC. Their structures have been elucidated by extensive 1D‐ and 2D‐NMR, and mass spectroscopic techniques. 相似文献
955.
Hossein Naeimi 《中国化学会会志》2008,55(5):1156-1159
The highly regioselective cleavage of epoxides into corresponding vicinal haloalcohols with elemental halogen has been catalyzed by hexamethylenetetramine (HMTA). This method occurred under neutral and mild conditions with high yields and short reaction times in various aprotic solvents even when sensitive functional groups were present. 相似文献
956.
Saied Saeed Hosseiny Davarani Ahmad PourahadiSaeed Nojavan Mohammad Hossein BanitabaMahnaz Nasiri-Aghdam 《Analytica chimica acta》2012
Electro membrane extraction (EME) as a new microextraction method was applied for extraction of sodium diclofenac (SDF) as an acidic compound from wastewater, urine, bovine milk and plasma samples. Under applied potential of 20 V during the extraction, SDF migrated from a 2.1 mL of sample solution (1 mM NaOH), through a supported liquid membrane (SLM), into a 30 μL acceptor solution (10 mM NaOH), exist inside the lumen of the hollow fiber. The negative electrode was placed in the donor solution, and the positive electrode was placed in the acceptor solution. 1-octanol was immobilized in the pores of a porous hollow fiber of polypropylene as SLM. Then the extract was analyzed by means of high-performance liquid chromatography (HPLC) with UV-detection for quantification of SDF. Best results were obtained using a phosphate running electrolyte (10 mM, pH 2.5). The ranges of quantitation for different samples were 8–500 ng mL−1. Intra- and inter-day RSDs were less than 14.5%. Under the optimized conditions, the preconcentration factors were between 31 and 66 and also the limit of detections (LODs) ranged from 2.7 ng mL−1 to 5 ng mL−1 in different samples. This procedure was applied to determine SDF in wastewater, bovine milk, urine and plasma samples (spiked and real samples). Extraction recoveries for different samples were between 44–95% after 5 min of extraction. 相似文献
957.
Biuck Habibi Mojtaba Jahanbakhshi Mohammad Hossein Pournaghi-Azar 《Mikrochimica acta》2012,177(1-2):185-193
A nanohybrid composite material was prepared from single-walled carbon nanotubes and silver nanoparticles, and used to fabricate a modified carbon-ceramic electrode. The preparation of the composite is facile and efficient. The nanohybrid composite deposited on the carbon-ceramic electrode was characterized by X-ray diffraction and cyclic voltammetry. The new electrode displays favorable electrocatalytic ability towards hydrogen peroxide (H2O2) and can be used to electrocatalytically reduce this species. Under the optimum conditions, the current measured during hydrodynamic amperometry is linearly related to the concentration of H2O2 over the concentration range from 0.01 to 8 mM, with a detection limit of 2?×?10?7 M at a signal-to-noise ratio of 3 and sensitivity of 3.23 μA/mM. The electrode exhibits good reproducibility, long-term stability and negligible interference by dopamine, uric acid, and other important biological compounds. The electrode was successfully applied to the determination of H2O2 in honey samples, and the recovery was 101.2%. Figure
CVs of bare CCE (a, a′) and SWCNT (b, b′) and SWCNT/AgNPs (c, c′) modified electrodes in phosphate buffer solution (0.1 M, pH 7.0) without and with 5 mM H2O2, respectively. Scan rate is 50 mVs?1. 相似文献
958.
Mahdi?SadeghiEmail author Nadia?Zandi Hossein?Afarideh 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(3):731-738
In recent years, there has been a rapid expansion in the use of radio nuclides for therapeutic purposes. Thulium–167 is an
important radionuclide (T
1/2 = 9.25 d) due to it could be used for tumor and bone studies in nuclear medicine. 167Tm complexed with hydroxy ethylene diamine tetra-acetic acid (HEDTA) could be used with the aim of bone imaging. 167Tm emits a prominent γ ray of 208 keV energy and low energy electrons. This study describes calculations on the excitation
functions of 165Ho(α,2n)167Tm, 167Er(p,n)167Tm, natEr(d,xn)167Tm and natEr(p,xn)167Tm reactions by ALICE/ASH (hybrid and GDH models) and TALYS-1.0 codes. In addition, calculated data by codes were compared
to experimental data that earlier were published and TENDL-2010 database. Moreover, optimal thickness of the targets and physical
yield were obtained by SRIM (stopping and range of ions in matter) code for each reaction. According to the results, the 167Er(p,n)167Tm and 165Ho(α,2n)167Tm reactions are suggested as the best method to produce 167Tm owing to minimum impurities. The TALYS-1.0 code, predict the maximum cross-section of about 382 mb at 11 MeV and 849 mb
at 26 MeV for 167Er(p,n)167Tm and 165Ho(α,2n)167Tm reactions, respectively. Finally, deposition of natEr2O3 on Cu substrate was carried out via the sedimentation method. The 516 mg of erbium(III)oxide with 103.2 mg of ethyl cellulose
and 8 mL of acetone were used to prepare a natEr2O3 layer of 11.69 cm2. 167Tm was produced via the natEr(p,n)167Tm nuclear process at 20 μA current and 15 → 7 MeV protons beam (1 h). Yield of about 3.2 MBq 167Tm per μA h were experimentally obtained. 相似文献
959.
Sayed Mehdi Ghoreishi Mohsen Behpour Samaneh Mazaheri Hossein Naeimi 《Journal of Radioanalytical and Nuclear Chemistry》2012,293(1):201-210
The electrochemical determination of uranyl was investigated by using carbon paste electrode modified with a Schiff base namely N,N??-bis(salicylidene)-2-hydroxy-phenylmethanediamine (SHPMD/CPE) and also in the presence of carbon nanotube (SHPMD/CNT/CPE). The both modified electrodes displayed an irreversible peak at E pa?=?0.798?V versus Ag/AgCl. The electrocatalytic reduction of uranyl has been studied on SHPMD/CNT/CPE, using cyclic and differential pulse voltammetry, chronocoulometry and linear sweep techniques. Electrochemical parameters including the diffusion coefficient (D), the electron transfer coefficient (??), the ionic exchange current (i) and the redox reaction rate constant (K) were determined for the reduction of uranyl on the surface of the modified electrodes. Linear range concentration is 0.002?C0.6???mol?L?1 and the detection limit of uranyl is 0.206?nmol?L?1. The proposed method was used to detect uranyl in natural waters and good recovery was achieved. 相似文献
960.
Gholam Hossein Rounaghi Behjat Deiminiat 《Journal of inclusion phenomena and macrocyclic chemistry》2012,72(1-2):113-119
The complexation reaction between Y3+ cation with N-phenylaza-15-crown-5(Ph-N15C5) was studied at different temperatures in acetonitrile–methanol (AN/MeOH), acetonitrile–propanol (AN/PrOH), acetonitrile–1,2 dichloroethane (AN/DCE) and acetonitrile–water (AN/H2O) binary mixtures using the conductometric method. The results show that in all cases, the stoichiometry of the complex is 1:1 (ML). The values of formation constant of the complex which were determined using conductometric data, show that the stability of (Ph-N15C5.Y)3+ complex in pure solvents at 25?°C changes in the following order: PrOH?>?AN?>?MeOH and in the case of binary mixed solutions at 25?°C it follows the order: AN–DCE?>?AN–PrOH?>?AN–MeOH?>?AN–H2O. The values of standard thermodynamic quantities (?H c ° and ?S c ° ) for formation of (Ph-N15C5.Y)3+ complex were obtained from temperature dependence of the formation constant using the van’t Hoff plots. The results show that in most cases, the complex is entropy and enthalpy stabilized and these parameters are influenced by the nature and composition of the mixed solvents. In most cases, a non-linear behavior was observed for variation of log Kf of the complex versus the composition of the binary mixed solvents. In all cases, an enthalpy–entropy compensation effect was observed for formation of (Ph-N15C5.Y)3+ complex in the binary mixed solvents. 相似文献