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101.
Column preconcentration and electrothermal atomic absorption spectrometric determination of rhodium in some food and standard samples 下载免费PDF全文
Mohammad Ali Taher Fatemeh Pourmohammad Hamid Fazelirad 《Journal of separation science》2015,38(23):4153-4158
In the present work, an electrothermal atomic absorption spectrometric method has been developed for the determination of ultra‐trace amounts of rhodium after adsorption of its 2‐(5‐bromo‐2‐pyridylazo)‐5‐diethylaminophenol/tetraphenylborate ion associated complex at the surface of alumina. Several factors affecting the extraction efficiency such as the pH, type of eluent, sample and eluent flow rates, sorption capacity of alumina and sample volume were investigated and optimized. The relative standard deviation for eight measurements of 0.1 ng/mL of rhodium was ±6.3%. In this method, the detection limit was 0.003 ng/mL in the original solution. The sorption capacity of alumina and the linear range for Rh(III) were evaluated as 0.8 mg/g and 0.015–0.45 ng/mL in the original solution, respectively. The proposed method was successfully applied for the extraction and determination of rhodium content in some food and standard samples with high recovery values. 相似文献
102.
103.
Hossein Eshghi Ali Javid Amir Khojastehnezhad Farid Moeinpour Fatemeh F. Bamoharram Mehdi Bakavoli Masoud Mirzaei 《催化学报》2015,(3)
A novel magnetic acidic catalyst comprising Preyssler (H14[NaP5W30O110]) heteropoly acid support‐ed on silica coated nickel ferrite nanoparticles (NiFe2O4@SiO2) was prepared. The catalyst was character... 相似文献
104.
Fatemeh Safdari Pierre J. Carreau Marie C. Heuzey Musa R. Kamal 《Cellulose (London, England)》2017,24(7):2877-2893
Polylactide (PLA)/cellulose nanofiber (CNF) biocomposites were prepared via solution casting and direct melt mixing. To improve the compatibility, a masterbatch of CNFs and poly(ethylene glycol) (PEG) (1:2) was also prepared. The effects of PEG on the morphology and properties of the biocomposites were investigated. The dispersion/distribution of nanofibers in PLA was improved when the masterbatch was used and the composites were prepared in solution. Substantial effects on the rheological properties of solution-prepared PLA/CNF/PEG composites were observed compared to composites containing no PEG, whereas for melt-prepared composites no significant changes were detected. Increased crystalline content and crystallization temperature were observed for the composites prepared via the masterbatch and solvent casting. The storage modulus of PLA was increased by 42 and 553% at 25 and at 80 °C, respectively, for the solution-based PEG-compatibilized composite containing 2 wt% nanofibers. Also, a better light transmittance was measured for the PLA/CNF/PEG composites prepared in solution. 相似文献
105.
Zonozi Fatemeh Beyramabadi S. Ali Pordel Mehdi Morsali Ali 《Research on Chemical Intermediates》2017,43(3):1829-1846
Research on Chemical Intermediates - The derivatives of acridine play important roles as dyes, drugs, and antiseptics. Herein, we have investigated the kinetics and the mechanism of the formation... 相似文献
106.
An efficient and straightforward approach to the synthesis of 2,3-dihydroquinazolin-4(1H)-one from 2-aminobenzamide and carbonyl compounds (aldehydes and ketones) using biocompatible choline sulfate-based acidic ionic liquid as a cheap and readily available catalyst in water has been developed. Various 2,3-dihydroquinazolin-4(1H)-one have been prepared using low-cost and environmental friendly solvent and catalyst in good to excellent yields in a shorter reaction time. The choline sulfate catalyst was prepared using a simple method from readily available starting material and was confirmed by 1H NMR, FTIR, and TGA. The ease of the product separation without organic solvent and column chromatography and the reusability of the acidic ionic liquid catalyst makes this method economically affordable for large-scale synthesis. 相似文献
107.
Fatemeh Shahangi Shirazi Kamran Akhbari 《Journal of the Iranian Chemical Society》2017,14(7):1519-1525
By considering the structure of one-dimensional pencil-shaped organometallic coordination polymer that was previously reported, we designed and synthesized [Na(μ2-Hdcpa)(μ3-dcpa)] n (1), [Hdcpa = 2,4-dichlorophenoxyacetic acid], which has one-dimensional pencil-shaped structure too. The Na atoms are surrounded with the aromatic phenyl rings of Hdcpa similar to graphite of a pencil. Metalophilic interactions also exists in 1 between Na(I) ions similar to argentophilic interaction in our previous compound which results in formation of chain structure similar to graphite structure of a pencil. Compound 1 nanorods were formed under ultrasonic irradiation and applied as template to fabricate sodium chloride nanorods. The interesting feature of our work is the formation of sodium chloride nanorods from compound 1 nanorods which have one-dimensional structure in the solid state. 相似文献
108.
In this paper, an efficient method for solving nonlinear Stratonovich Volterra integral equations is proposed. By using Bernoulli polynomials and their stochastic operational matrix of integration, these equations can be reduced to the system of nonlinear algebraic equations with unknown Bernoulli coefficient which can be solved by numerical methods such as Newton’s method. Also, an error analysis is valid under fairly restrictive conditions. Furthermore, in order to show the accuracy and reliability of the proposed method, the new approach is compared with the block pulse functions method by some examples. The obtained results reveal that the proposed method is more accurate and efficient than the block pulse functions method. 相似文献
109.
Fatemeh Niroomand Hosseini Alireza Ariafard Gholamhassan Azimi 《Journal of organometallic chemistry》2011,696(21):3351-3358
Three metal square planar complexes of the type [M(CH3)2(NH3)2] (M = Ni, Pd, Pt), with a systematic variation in the metals, are chosen to investigating their SN2-type oxidative addition reactions with methyl iodide by using the B3LYP levels of theory. The oxidative addition was found to take place via a transition state with a nearly linear arrangement of the I-CH3-M moiety. Solvation effects in these oxidative addition reactions were also investigated. Considering the nature of the metal centre and solvation effects, the following conclusions emerge: (i) addition of MeI is exothermic for all three metals, and Pt is predicted to react with a much lower barrier than either Pd or Ni. The results describe that the MeI addition would be expected to be more favourable with the complex bearing the third-row metal (platinum) as compared to the other triad metals, nickel or palladium, in which case a more strongly bound MeI adduct is formed with a lower activation barriers and the reaction being more exothermic; (ii) the reaction is very difficult to occur in low polar solvents, such as benzene, due to the high barrier which is induced by dissociation of iodide anion from methyl group, but the reaction easily occurs in polar solvents, such as acetonitrile; this is attributed to the ability of polar solvents to solvate and therefore stabilize the related polar intermediate ion pair. Ethane reductive elimination from the M(VI) complexes fac-[M(CH3)3(NH3)2I] were also studied, indicating that the Ni(IV) and Pd(IV) complexes are very prone to undergo the reductive elimination while the Pt(IV) analogous is less reactive towards the reductive elimination. The results indicate that in contrast to the Me-Me reductive elimination, the SN2 oxidative addition reaction of MeI to M(II) is much less sensitive to the nature of the metal centre, suggesting that the nucleophilicity of M(II) in [M(CH3)2(NH3)2] does not change significantly as one moves from M = Ni to Pt. 相似文献
110.
Seyedeh Fatemeh Hojati Behrooz Maleki Zahra Beykzadeh 《Monatshefte für Chemie / Chemical Monthly》2011,14(3):87-91