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Bahador Abolpour Roozbeh Abolpour Arash Shamseddini Saideh Kamyabi Farahnaz Hamzehee 《Research on Chemical Intermediates》2013,39(2):681-692
In this paper, the enthalpy-concentration method was applied in order to model a steady-state continuous methanol–water mixture distillation column. This work includes three steps; first, to develop a code in MATLAB v.7.6 to apply to the mathematical model of the column. The second step is to simulate the column using HYSIS v.3.2. While the third is the calculation of the optimized reflux ratio to minimize the operating cost. For a distillation tower such as the methanol–water splitter in this study, there are relatively few degrees of freedom that can be manipulated in order to minimize operating costs; the reflux ratio can influence the steady-state operating point and therefore the daily costs. In this paper, we have discussed the trade-offs between reflux ratios and operating costs. A correlation is derived to define the optimum value of the reflux ratio as an exponential function of a certain economic parameter of energy prices and depreciation costs. We demonstrate that, at low energy prices or high equipment depreciation costs, the optimum reflux factor is high. 相似文献
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Farahnaz Nourmohammadian Mahnaz Davoudzadeh Gholami 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):340-346
A convenient and efficient, regioselective, solvent-free procedure has been developed to react 2,6-dihydroxyanthraquinone, dialkyl acetylenedicarboxylates, and triphenylphosphine in one-pot, to afford novel phosphanylidene anthracenyl derivatives 3a-c, which at 90°C due to intramolecular nucleophilic attack formed novel phosphanylidene anthra[2,1-b]furans 4a–c in good yield. 相似文献
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Hossein A. Oskooie Majid M. Heravi Maryam H. Tehrani Farahnaz K. Behbahani Omid M. Heravi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1729-1737
In this article, a mild and efficient protocol for the trimethylsilylation of various aliphatic and benzylic alcohols and phenols with trimethylsilyl chloride using a catalytic amount of ferric perchlorate at room temperature and relatively short reaction times in good to excellent yields is reported. Direct acetylation of trimethylsilyl ethers catalyzed with Fe(ClO 4 ) 3 .6H 2 O(0.02 mmol)/Fe(ClO 4 ) 3 SiO 2 (0.2 g) using acetic anhydride at ambient temperature is also reported. 相似文献
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Here, the synthesis of two novel series of dichromophoric cyanine dyes were reported. The first series of novel bis-azacyanine dyes 3a–d was afforded by reaction of 2-(1,3,3-trimethyle indoline-2-ylidene)acetaldehyde with diaminoaromatics, and the second series of novel bis-diazacyanine dyes 4a–d was obtained using quaternization of an amine group in disazo compounds, which were produced by the reaction of disazoaromatics with 2-methylene-1,3,3-trimethyle indoline. The products were identified by 1H NMR, 13C NMR, infrared, UV-vis, and mass spectroscopy. 相似文献
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Nour-Mohhamadi F Nguyen SD Boschloo G Hagfeldt A Lund T 《The journal of physical chemistry. B》2005,109(47):22413-22419
The oxidative degradation rate, kdeg, of the solar cell dye (Bu4N+)2[Ru(dcbpyH)2(NCS)2]2-, referred to as N719 or [RuL2(NCS)2], was obtained by applying a simple model system. Colloidal solutions of N719-dyed TiO2 particles in acetonitrile were irradiated with 532-nm monochromatic light, and the sum of the quantum yields for the oxidative degradation products [RuL2(CN)2], [RuL2(NCS)(CN)], and [RuL2(NCS)(ACN)], Phideg, was obtained at eight different light intensities in the range of 0.1-16.30 mW/cm2 by LC-UV-MS. The Phideg values decreased from 3.3 x 10-3 to 2.0 x 10-4 in the applied intensity range. By using the relation kdeg = Phidegkback and back electron-transfer reaction rates, kback, obtained with photoinduced absorption spectroscopy, it was possible to calculate an average value for the oxidative degradation rate of N719 dye attached to TiO2 particles, kdeg = 4.0 x 10-2 s-1. The stability of N719 dye during solar cell operation was discussed based on this number, and on values of the electron-transfer rate between [Ru(III)L2(NCS)2] and iodide ion that are available in the literature. 相似文献
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Behforouz M Haddad J Cai W Arnold MB Mohammadi F Sousa AC Horn MA 《The Journal of organic chemistry》1996,61(19):6552-6555
The novel 7-(N-formyl-, 7-(N-acetyl-, and 7-(N-isobutyrylamino)-2-methylquinoline-5,8-diones were synthesized in excellent overall yields in three steps via the nitration of the commercially available 8-hydroxy-2-methylquinoline followed by a reduction-acylation step and then oxidation. Acid hydrolysis of 7-(N-acetylamino)-2-methylquinoline-5,8-dione (14a) afforded the novel 7-aminoquinoline-5,8-dione 7 in excellent yields. Due to our efficient preparation of dione 14a, we now report a short and practical method for the total synthesis of the potent antitumor agent lavendamycin methyl ester (1b) with an excellent overall yield. 相似文献
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Masoud Shariati-Rad Mohsen Irandoust Farahnaz Niazi 《Journal of Analytical Chemistry》2016,71(7):660-666
A method for the determination of nitrite in soil and vegetable samples by UV-Vis spectroscopy was proposed. The kinetic UV-Vis data were collected during the reaction between nitrite and 4-amino-3-hydroxynaphthalene-1-sulfonic acid with concentration of 0.001 M and pH 1.6. Data were collected by standard addition method. Multivariate curve resolution-alternating least squares was employed to analyze data with non-negativity and three-way data structure constraints. The method can be used to solve matrix effect and unknown interferents in the determination of nitrite in complex samples. The proposed method was used to determine nitrite at low mg/L levels with satisfactory results in soil, lettuce, cabbage and cucumber samples. 相似文献
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New equation for calculating total interaction energy in one noncyclic ABC triad and new insights into cooperativity of noncovalent bonds 下载免费PDF全文
In this work, a new equation consist of A???B, B???C, A???BC, and AB???C interactions is proposed for calculating the total interaction energy of noncyclic ABC triads. New equations are also proposed for calculating the changes in values of A???B and B???C interactions on the formation of triad from the corresponding dyads. The advantages of equations proposed here in comparison with many‐body interaction energy approach are discussed. All proposed equations were tested in F3MLi???NCH???HLH and F3MLi???HLH???HCN (M = C, Si; L = Be, Mg) as well as H3N???XY???HF (X, Y = F, Cl, Br) noncyclic A???B???C triads. The data show that the total cooperativity of triad correlates well with the sum of the changes in values of A???B and B???C interactions calculated through new equations proposed here. © 2016 Wiley Periodicals, Inc. 相似文献
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