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91.
Abdolali Alizadeh 《Helvetica chimica acta》2005,88(2):304-308
Different esters of 2‐aryl‐4‐hydroxy‐3‐nitro‐5‐(triphenylphosphoranylidene)cyclopenta‐1,3‐diene‐1‐carboxylates 1 were prepared in excellent yields from the 1 : 1 : 1 reaction between Ph3P, dialkyl acetylenedicarboxylates 2 , and (substituted) 2‐(nitroethenyl)benzenes 3 (Scheme 1). The structures of the highly functionalized compounds 1 were corroborated spectroscopically (IR, 1H‐, 13C‐, 31P‐NMR, EI‐MS) and by elemental analyses. A plausible mechanism for this type of cyclization is proposed (Scheme 2). 相似文献
92.
Forouzan Zonouzi Alireza Shayesteh Taher Alizadeh Hamid Dezhampanah Bahram Ghalami-Choobar Afsaneh Zonouzi 《中国化学会会志》2020,67(1):41-45
The (E)-2-hydroxy-5-(aryldiazenyl) benzaldehydes (azo dyes 1–4 ) were synthesized in high purity. As they are insoluble in water, the usual analytical methods cannot be utilized to determine their pKa values. Cyclic voltammetry was experimentally used to determine their pKa values in DMSO solvent. In addition, computational methods and a conductor-like screening model (COSMO) were used to calculate the solvent effect. , , Kexchange, and pKa values were estimated for the azo dyes being studied using the BP86, TPSS, B3LYP, PBE0, TPSSh, and PW6B95 density functionals in def2-TZVP basis sets. The obtained mean absolute deviations (MADs) indicate that the results of BP86, PBE0, and PW6B95 functionals are in good agreement with experimental values. 相似文献
93.
94.
The electrochemical fiber coating (EFC) technique was used for the preparation of dodecylsulfate-doped polypyrrole (PPy-DS), and applied as a new fiber for solid-phase microextraction (SPME) procedures. PPy-DS film was directly electrodeposited on the surface of a platinum wire from an aqueous solution containing pyrrole and sodium dodecylsulfate, using cyclic voltammetry (CV). The effect of polymerization conditions and type of dopants on the thermal stability, adhesion and extraction characteristics of the fiber were investigated. The electron microscopy imaging of PPy-DS film suggested that the surface fiber coating was well-distributed with a porous structure. The fiber coating can be prepared easily in a reproducible manner, and it is inexpensive and has a stable performance at high temperatures (up to the 300 degrees C). The extraction properties of the fiber to eight polycyclic aromatic hydrocarbons (PAHs) were examined, using a headspace-SPME (HS-SPME) device coupled with gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The results revealed study shows that PPy-DS as a SPME fiber coating is suitable for the successful extraction of PAHs. The effects of the extraction parameters including exposure time, sampling temperature, salt concentration, and stirring rate on the extraction efficiency have been studied. A satisfactory reproducibility for extractions from spiked water samples at PPb-level with R.S.D. < 7.6% (n = 7) was obtained. The calibration graphs were linear in the range of 0.5-100ng ml(-1) and detection limits for the selected PAHs were between 0.05-0.16 ng ml(-1). Comparing the HS-SPME results for extraction and determination of PAHs using PPy-DS fiber with the corresponding literature data using PDMS fiber shows that the proposed fiber has a better detection limit for low molecular weight PAHs. The life span and stability of PPy-DS fiber is good and it can be used more than 50 times at 250 degrees C without any significant change in sorption properties. 相似文献
95.
Determination of three antidepressants in urine using simultaneous derivatization and temperature‐assisted dispersive liquid–liquid microextraction followed by gas chromatography–flame ionization detection
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Ali Akbar Alizadeh Nabil Nina Nouri Mir Ali Farajzadeh 《Biomedical chromatography : BMC》2015,29(7):1094-1102
This paper presents a fast and simple method for the extraction, preconcentration and determination of fluvoxamine, nortriptyline and maprotiline in urine using simultaneous derivatization and temperature‐assisted dispersive liquid–liquid microextraction (TA‐DLLME) followed by gas chromatography–flame ionization detection (GC‐FID). An appropriate mixture of dimethylformamide (disperser solvent), 1,1,2,2‐tetrachloroethane (extraction solvent) and acetic anhydride (derivatization agent) was rapidly injected into the heated sample. Then the solution was cooled to room temperature and cloudy solution formed was centrifuged. Finally a portion of the sedimented phase was injected into the GC‐FID. The effect of several factors affecting the performance of the method, including the selection of suitable extraction and disperser solvents and their volumes, volume of derivatization agent, temperature, salt addition, pH and centrifugation time and speed were investigated and optimized. Figures of merit of the proposed method, such as linearity (r2 > 0.993), enrichment factors (820–1070), limits of detection (2–4 ng mL?1) and quantification (8–12 ng mL?1), and relative standard deviations (3–6%) for both intraday and interday precisions (concentration = 50 ng mL?1) were satisfactory for determination of the selected antidepressants. Finally the method was successfully applied to determine the target pharmaceuticals in urine. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
96.
M.H. Alizadeh 《Optimization》2013,62(6):693-701
A new definition of monotone bifunctions is given, which is a slight generalization of the original definition given by Blum and Oettli, but which is better suited for relating monotone bifunctions to monotone operators. In this new definition, the Fitzpatrick transform of a maximal monotone bifunction is introduced so as to correspond exactly to the Fitzpatrick function of a maximal monotone operator in case the bifunction is constructed starting from the operator. Whenever the monotone bifunction is lower semicontinuous and convex with respect to its second variable, the Fitzpatrick transform permits to obtain results on its maximal monotonicity. 相似文献
97.
Equilibrium and kinetic study of novel methyltrimethoxysilane magnetic titanium dioxide nanocomposite for methylene blue adsorption from aqueous media
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Parvin Alizadeh Eslami Mohammad Afzal Kamboh Hamid Rashidi Nodeh Wan Aini Wan Ibrahim 《应用有机金属化学》2018,32(6)
Novel magnetic titanium dioxide nanoparticles decorated with methyltrimethoxysilane (Fe3O4@TiO2‐MTMOS) were successfully fabricated via a sol–gel method at room temperature. The synthesized material was characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, thermogravimetric analysis and vibrating sample magnetometry. The removal efficiency of the adsorbent was evaluated through the adsorption of methylene blue (MB) dye from water samples. The adsorption isotherm and kinetics were evaluated using various models. The Langmuir model indicated a high adsorption capacity (11.5 mg g?1) of Fe3O4@TiO2‐MTMOS. The nanocomposite exhibited high removal efficiency (96%) and good regeneration (10 times) compared to Fe3O4 and Fe3O4@TiO2 at pH = 9.0. Based on the adsorption mechanism, electrostatic interaction plays a main role in adsorption since MB dye is cationic in nature at pH = 9, whereas the adsorbent acquired an anionic nature. The newly synthesized Fe3O4@TiO2‐MTMOS can be used as a promising material for efficient removal of MB dye from aqueous media. 相似文献
98.
99.
Jobbitt N. L. Patchett S. J. Alizadeh Y. Reid M. F. Wells J.-P. R. Horvath S. P. Longdell J. J. Ferrier A. Goldner P. 《Physics of the Solid State》2019,61(5):780-784
Physics of the Solid State - Zeeman spectroscopy is used to demonstrate that phenomenological crystal-field parameters determined for the two C1 point-group symmetry sites in Er3+:Y2SiO5 may be... 相似文献
100.
Hydrogen peroxide/MoO3, as an efficient and clean oxidizing system was used to afford diasteroselective oxidative cyclization of bisnaphthols to spirans in ethanol at 60 °C with high yields. Bisnaphthols were prepared by the reaction of a series of aldehydes and 2-naphthol in the presence of a catalytic amount of H3[P(Mo3O10)4].nH2O (HPa) in refluxing dichloromethane. 相似文献