Search for: solvent
Total 443 records
Synergistic effect of MEHPA on co-extraction of zinc and cadmium with DEHPA, Article Minerals Engineering ; Volume 17, Issue 1 , 2004 , Pages 89-92 ; 08926875 (ISSN) ; Moradkhani, D ; Darvishi, D ; Askari, M ; Behnian, D ; Sharif University of Technology
Simultaneous extraction of zinc and cadmium by a mixture of di-2-ethyl hexyl phosphoric acid (DEHPA) and mono-2-ethyl hexyl phosphoric acid (MEHPA), and the synergistic effect of MEHPA on co-extraction of zinc and cadmium with DEHPA have been investigated. It was shown that the extraction of zinc and cadmium by DEHPA and/or MEHPA can be increased by an increase of pH. The results also illustrate that the pH0.5 of zinc, by increase in MEHPA from 0.1 to 8 vol%, did not vary significantly while that of cadmium varies from 0.63 to 2.4. In other words MEHPA prevents selective extraction of zinc from aqueous media containing both zinc and cadmium. Studies on the selective separation parameter...
Reaction kinetics investigation of 1-fluoro-2,4-dinitrobenzene with substituted anilines in ethyl acetate–methanol mixtures using linear and nonlinear free energy relationships, Article Journal of Physical Organic Chemistry ; Volume 24, Issue 11 , November , 2011 , pages 1095–1100 ; Harifi-Mood, A. R. (Ali Reza) ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
Aromatic nucleophilic substitution reaction of 1-fluoro-2,4-dinitrobenzene with para-substituted and meta-substituted anilines was kinetically investigated in the mixtures of ethyl acetate and methanol at room temperature. The correlation of second-order rate coefficients with Hammett's substituent constants yields a fairly linear straight line with negative slope in different mole fractions of ethyl acetate–methanol mixtures. The measured rate coefficients of the reaction demonstrated a dramatic variation in ethyl acetate–methanol mixtures with the increasing mole fraction of ethyl acetate. Linear free energy relationship (LFER) investigations confirm that polarity has a major effect on the...
Solvatochromic Probes Absorbance Behavior in Mixtures of 2-Hydroxy ethyl ammonium formate with methanol, ethylene glycol and glycerol, Article Journal of Solution Chemistry ; Volume 39, Issue 10 , October , 2010 , pp 1509-1519 ; Harifi-Mood, A. R. (Ali Reza) ; Elahifard, M. R. (Mohammad Reza) ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
Solute-solvent and solvent-solvent interactions were investigated for binary mixtures of an ionic liquid (IL) 2-hydroxy ethylammonium formate as with methanol, ethylene glycol and glycerol. The physicochemical properties of the solvent mixtures at 25 °C, over the whole range of mole fractions, were determined using solvatochromic probes. High normal polarity ( ENT ) in the alcohol-rich region confirms solute-solvent interactions in this medium. Dipolarity/polarizability (π ∗) show a different trend to ENT with a positive deviation from ideal behavior in IL-glycerol mixtures. However, these deviations for other solvent mixtures are insignificant. Contrary to what is observed for ENT and π ∗,...
Solvatochromic probes absorbance behavior in mixtures of 2-hydroxy ethylammonium formate with methanol, ethylene glycol and glycerol, Article Journal of Solution Chemistry ; Volume 39, Issue 10 , 2010 , Pages 1509-1519 ; 00959782 (ISSN) ; Harifi Mood, A. R ; Elahifard, M. R ; Gholami, M. R ; Sharif University of Technology
Solute-solvent and solvent-solvent interactions were investigated for binary mixtures of an ionic liquid (IL) 2-hydroxy ethylammonium formate as with methanol, ethylene glycol and glycerol. The physicochemical properties of the solvent mixtures at 25 °C, over the whole range of mole fractions, were determined using solvatochromic probes. High normal polarity (ETN) in the alcohol-rich region confirms solute-solvent interactions in this medium. Dipolarity/polarizability (π *) show a different trend to ETN with a positive deviation from ideal behavior in IL-glycerol mixtures. However, these deviations for other solvent mixtures are insignificant. Contrary to what is observed for E TN and π*,...
Preparation of ethyl cellulose microcapsules containing perphenazine and polymeric perphenazine based on acryloyl chloride for physical and chemical studies of drug release control [electronic resource], Article Polymer International ; Volume 47, Issue 4, pages 413–418, December 1998 ; Pourjavadi, A ; Hashemi, S. A ; Arabi. , H ; Sharif University of Technology
The preparation of microcapsules containing perphenazine by solvent evaporation using ethyl cellulose is described. The microparticles are formed after solvent evaporation and polymer precipitation. The drug was dissolved in a polymer solution and emulsified into an aqueous phase to form microcapsules. To study the effects on particle size, encapsulation efficiency and morphology, three different molecular weights of ethyl cellulose (Mw=47000, 71000 and 99000) were used. Covalent bonding of drugs to polymers via hydrolytically or enzymatically cleavable covalent bond was achieved for sustained drug delivery. The release rate of perphenazine from these systems was investigated
Transition metal-free addition of dithiocarbamates to alkynes: One-pot regioselective synthesis of S-vinyl dithiocarbamates under solvent-free conditions, Article Monatshefte fur Chemie ; Vol. 145, issue. 3 , 2014 , pp. 521-526 ; ISSN: 00269247 ; Saidi, M. R ; Sharif University of Technology
A convenient, green, and efficient procedure for the synthesis of S-vinyl dithiocarbamates by a simple one-pot three-component condensation of an amine, carbon disulfide, and alkynes is described in the absence of any transition metal catalyst and under solvent-free conditions. This clean and improved method selectively furnishes the corresponding (Z)-S-vinyl dithiocarbamates in good to excellent yields. The reaction is clean with simple product workup and is carried out at 80 C. Graphical Abstract: [Figure not available: see fulltext.]
Solvent-free dehydration of alcohols using LiCI-acidicalumina, Article Oriental Journal of Chemistry ; Volume 28, Issue 3 , 2012 , Pages 1141-1145 ; 0970020X (ISSN) ; Pourjavadi, A ; Hosseinzadeh, H ; Sharif University of Technology
Conjugated enynes, dienes and simple olefins have been cleanly and selectively synthesized, good-to-excellent yields, by dehydration of corresponding alcohols using focused microwave irradiation on the surface of LiCI-acidic alumina
Metal-Organic cubane cage with trimethylplatinum(Iv) vertices, Article Inorganic Chemistry ; 2021 ; 00201669 (ISSN) ; Jamali, S ; Mahmoudi, S ; Samouei, H ; Nayeri, S ; Chabok, S. M. J ; Jamshidi, Z ; Sharif University of Technology
American Chemical Society 2021
Herein we describe the synthesis and characterization of the first platinum(IV) metal-organic cage [(Me3PtIV)8(byp)12](OTf)8 (2), in which the organometallic moieties trimethylplatinum(IV) (PtMe3) occupied the corners of a cubane structure and 4,4′-bipyridine ligands used as linkers. The first-principles density functional theory calculations showed that the highest occupied molecular orbitals were localized on the PtMe3 moieties, while the lowest unoccupied molecular orbitals were distributed on the organic linkers. © 2021 American Chemical Society
Immersed solvent microextraction of phenol and chlorophenols from water samples followed by gas chromatography-mass spectrometry, Article Journal of Chromatography A ; Volume 1046, Issue 1-2 , 2004 , Pages 27-33 ; 00219673 (ISSN) ; Saber, A ; Mousavi, S. R ; Sharif University of Technology
A homemade immersed solvent microextraction (SME) device was successfully developed for the trace enrichment of phenols from aqueous samples. A microdrop of butyl acetate was suspended from the tip of a microsyringe needle, immersed in an aqueous spiked solution for a preset time. The microdrop was then retracted into the microsyringe and injected directly into a gas chromatography-mass spectrometry (GC-MS) injection port. Effects of different parameters such as the type of solvent, extraction time, stirring rate, and temperature were investigated and optimized. To reduce the polarity of phenols and prevent tailing effects, all the phenols were derivatized prior to extraction using acetic...
Lithium perchlorate-catalyzed three-component coupling: a facile and general method for the synthesis of α-aminophosphonates under solvent-free conditions, Article European Journal of Organic Chemistry ; Issue 23 , 2003 , Pages 4630-4633 ; 1434193X (ISSN) ; Saidi, M. R ; Sharif University of Technology
Wiley-VCH Verlag 2003
A simple, efficient, and general method has been developed for the synthesis of α-aminophosphonates in the presence of solid lithium perchlorate under solvent-free conditions. Thus secondary and tertiary α-aminophosphonates were synthesized relatively quickly in good yields at room temperature. © Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003
Microwave-assisted aminomethylation of electron-rich compounds under solvent-free condition, Article Synthetic Communications ; Volume 30, Issue 1 , 2000 , Pages 69-72 ; 00397911 (ISSN) ; Sharifi, A ; Mohsenzadeh, F ; Saidi, M. R ; Sharif University of Technology
Marcel Dekker Inc 2000
Electron-rich aromatic compounds react with formaldehyde and a secondary amine under solvent-free condition, in the presence of acidic alumina in a commercial microwave oven or at room temperature to produce aminomethylated products in good to excellent yields
Molecular-microscopic properties and preferential solvation in protic ionic liquid mixtures, Article Journal of Solution Chemistry ; Volume 42, Issue 9 , October , 2013 , pp. 1757-1769 ; 1572-8927 ; Ahmadvand, S. (Seyedsaeid) ; Harifi-Mood, A. R. (Ali Reza) ; Padervand, M. (Mohsen) ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
Structural and molecular-microscopic properties of the solvatochromic probes 4-nitroaniline, 4-nitroanisole, and Reichardt’s dye were investigated in binary mixtures of ethylammonium propionate with methanol, ethanol, 1-propanol and 2-propanol. Solvatochromic parameters (α, hydrogen-bond donor acidity; β, hydrogen-bond acceptor basicity; π*, dipolarity/polarizability; ENT , normalized polarity parameter) in different binary mixtures of ionic liquid with molecular solvents were determined with UV–Vis spectroscopy. The ENT parameters show nearly ideal trends in all solvent mixtures, but the other parameters show different behavior in the mixtures. The π* parameters show a negative deviation...
Molecular-microscopic properties and preferential solvation in protic ionic liquid mixtures, Article Journal of Solution Chemistry ; Volume 42, Issue 9 , 2013 , Pages 1757-1769 ; 00959782 (ISSN) ; Ahmadvand, S ; Harifi-Mood, A. R ; Padervand, M ; Gholami, M. R ; Sharif University of Technology
Structural and molecular-microscopic properties of the solvatochromic probes 4-nitroaniline, 4-nitroanisole, and Reichardt's dye were investigated in binary mixtures of ethylammonium propionate with methanol, ethanol, 1-propanol and 2-propanol. Solvatochromic parameters (α, hydrogen-bond donor acidity; β, hydrogen-bond acceptor basicity; π*, dipolarity/ polarizability; ET N, normalized polarity parameter) in different binary mixtures of ionic liquid with molecular solvents were determined with UV-Vis spectroscopy. The ET N parameters show nearly ideal trends in all solvent mixtures, but the other parameters show different behavior in the mixtures. The πparameters show a negative deviation...
LiClO4 • 3H2O promoted highly regioselective ring-opening of epoxides with thiols under neutral conditions, Article Catalysis Communications ; Volume 7, Issue 4 , 2006 , Pages 224-227 ; 15667367 (ISSN) ; Saidi, M. R ; Sharif University of Technology
A simple, rapid, atom economy and highly efficient procedure has been developed for thiolysis of epoxides by aromatic and aliphatic thiols under solvent-free conditions. A high regioselectivity in favor of nucleophilic attack at the benzylic carbon atom of aromatic epoxides, such as styrene oxide, is observed. However, aliphatic unsymmetrical alkenyl oxides undergo selective nucleophilic attack at the sterically less hindered carbon atom. A variety of β-hydroxy sulfides were obtained in short reaction time and excellent yields with nearly complete regioselectivity. © 2005 Elsevier B.V. All rights reserved
A simple approach to the synthesis of 3-substituted rhodanines and thiazolidine-2,4-diones, Article Scientia Iranica ; Volume 20, Issue 6 , 2013 , Pages 1833-1838 ; 10263098 (ISSN) ; Shokri, A ; Saidi, M. R ; Sharif University of Technology
Sharif University of Technology 2013
A novel synthesis of 3-substituted rhodanine and thiazolidine-2,4-dione derivatives, starting from aliphatic primary amines, carbon disulfide, and methyl 2-bromoacetate, is described. The reaction proceeds successfully both in water and under solvent-free conditions, but 2-thioxothiazolidin-4-one (rhodanine) derivatives were obtained under solvent free-conditions, and thiazolidine-2,4-dions were formed when water was used as the solvent
Surfactant binary systems: Ab initio calculations, preferential solvation, and investigation of solvatochromic parameters, Article Journal of Chemical and Engineering Data ; Volume 61, Issue 1 , 2016 , Pages 255-263 ; 00219568 (ISSN) ; Salari, H ; Fakhraee, M ; Gholami, M.R ; Sharif University of Technology
American Chemical Society
Solvatochromic UV-vis shifts of three probes 4-nitroaniline, 4-nitroanisol, and Reichardt's dye in binary mixtures of polyethylene glycol p-(1,1,3,3-tetramethylbutyl)-phenyl ether (Triton X-100 or TX-100) with methanol, ethanol, 1-propanol, and water have been investigated at 298 K. Structural and intermolecular interactions of solvatochromic probes were determined in these systems. Solvatochromic parameters, including normalized polarity (ETN), dipolarity-polarizability (π∗), hydrogen-bond donor (α), and hydrogen-bond acceptor (β) abilities, were measured at a wide range of mole fraction (0 ≤ X ≤ 1) with 0.1 increment. Interestingly, a similar behavior of ETN and α is observed in...
Experimental and Theoretical Study of the Lipid Extraction from Wet Microalgae for Biodiesel Production, M.Sc. Thesis Sharif University of Technology ; Rashtchian, Davood ; Vossoughi, Manoochehr
In this study, different stages of biodiesel production from microalgae were investigated, specifically the extraction step.Various cultivation methods were also studied among which cultivation under stress was the best. Different carbon sources were also investigated to achieve highest growth. Sodium acetate with complete growth was achieved after 8 days with 6.22% fatty acid recovery. Different mixtures of solvents were compared with Blye and Dier method. Results showed that the mixture of hexane and methanol with crude lipid extraction of 15% and fatty acid recovery of 3.97% were chosen as the solvent mixture of equilibria experiments.Organic solvent composed of hexane (non-polar...
Improving the Remediation Process of Asphaltene Deposits in the Well Facility of Koupal-Bangestan Oil Reservoir, M.Sc. Thesis Sharif University of Technology ; Ayatollahi, Shahaboddin ; Ghotbi, Cyrus
Crude oil production could cause the thermodynamic equilibrium of the crude oil to be disturbed in the well column which results in asphaltene precipitation and deposition. The thickness of the deposited material grows over time until it completely blocks the well column.Due to the hard and insoluble nature of deposited asphaltene, the two main chemical and mechanical methods are found to be more effective. It should be noted that the actual organic sediments in the piping are not pure and consist of three components: asphaltene, resin and paraffin. Therefore, it is very important to know the composition of the deposited material before selecting the appropriate chemical solvent.The samples...
Solvent-free synthesis of 3-benzylpyrano[3,2-c]pyran/chromene-2,5-diones via tandem reaction of 4-hydroxy-6-methyl-pyran-2-one and 4-hydroxycoumarin with Baylis-Hillman adduct acetates, Article Scientia Iranica ; Vol. 21, issue. 3 , 2014 , p. 735-741 ; 1026-3098 ; 2345-3605 ; Koushki Foroushani, B ; Lotfi Kalahroodi, E ; Sharif University of Technology
4-hydroxycoumarin 2a and 4-hydroxy-6-methyl-pyran-2-one 2b were applied in a one-pot reaction with Baylis-Hillman adduct acetates 1 to form novel 3-benzylpyrano [3, 2-c] pyran-2, 5-diones 3 in high yields (70-85%). The synthesized framework is available in many biologically active moieties. The reaction was carried out under different conditions to achieve optimum conditions. The results indicated that Et3N, as a base under solvent-free conditions, was optimum. The reaction procedure and purification method are mild and straightforward
Separation of Re and Mo from roasting-dust leach-liquor using solvent extraction technique by TBP, Article Separation and Purification Technology ; Volume 86 , February , 2012 , Pages 143-148 ; 13835866 (ISSN) ; Darvishi, D ; Haghshenas, D. F ; Yousefi, N ; Sadrnezhaad, S. K ; Sharif University of Technology
Re/Mo separation is studied by a new solvent extraction technique which is based on extraction mechanisms of the constituent metals. Based on McCabe-Thiele plots, a flow diagram has been proposed for separation and purification of Re over Mo. Re-recovery section of the diagram shows that Re is extracted when major amount of Mo is removed. For removal of the remained Mo, a two-stage extraction is required at pH = 2 and V a/V o = 1. In order to obtain Re, the resulted aqueous phase is stripped by adding sulfuric acid. According to the results, while more Re is extracted at less pH, optimum extraction of Mo happens at pH = 1.2. Re selectivity over Mo maximizes by approaching of the pH to zero