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Systems designed with an ionic liquid and molecular solvents to investigate the kinetics of an SNAr reaction
, Article Progress in Reaction Kinetics and Mechanism ; Volume 38, Number 2 , 2013 , pp. 157-170 ; Padervand, M. (Mohsen) ; Gholami, M. R. (Mohammad Reza) ; Hallett, Jason P ; Sharif University of Technology
Abstract
The microscopic features of binary solvent systems formed by molecular solvents (methanol, ethanol, 2-methylpropan-2-ol, water, pyridine, acetonitrile, 1-propanol, 2-propanol, dimethylformamide) and the ionic liquid ([bmim]BF4) as cosolvent were used to select mixed solvents with particular characteristics. Molecular-microscopic solvent parameters corresponding to these binary mixtures were utilised to study the kinetics of the nucleophilic substitution reaction between 2-chloro-3,5-dinitropyridine and aniline to investigate and compare the effects of the solvents on a model chemical reaction. For these mixtures, the solvation behaviour is dominated by both the dipolarity/ polarisability and...
Effects of Pr doping and magnetic field on vortex pinning in Gd-123 based HTSC
, Article Physica Status Solidi C: Conferences ; Volume 1, Issue 7 , 2004 , Pages 1883-1886 ; 16101634 (ISSN) ; Akhavan, M ; Sharif University of Technology
2004
Abstract
The magnetoresistance of single phase polycrystalline Gd(Ba 2-xPrx)Cu3O7-δ samples have been studied within thermally activated flux creep model. The decrease of pinning energy with applied magnetic field can be scaled to two power law relations for magnetic fields, smaller and also larger than about 1 kOe. The derived pinning energy shows that the Pr-doping, similar to weak links, decreases the vortex flux pinning energy. It is also concluded that the substitution of Pr at Ba site has a more destructive effect on the flux dynamics than Pr at rare earth site. © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Solvent parameters effects on the second-order rate constants of the reaction of 2-chloro-3,5-dinitropyridine with aniline in aqueous solutions of alcohols
, Article Progress in Reaction Kinetics and Mechanism ; Volume 31, Issue 2 , 2006 , Pages 117-127 ; 14686783 (ISSN) ; Masumpour, M. S ; Gholami, M. R ; Sharif University of Technology
Science Reviews Ltd
2006
Abstract
Aromatic nucleophilic substitution reaction kinetics of 2-chloro-3,5-dinitropyridine with aniline was studied in aqueous solutions of methanol, ethanol, and 2-propanol at room temperature. The obtained results for aqueous solutions indicate that the second-order rate constants are in order of 2-propanol>ethanol>methanol with a maximum at water mole fraction of 0.9. The influence of solvent parameters including normalized polarity (E TN), dipolarity/polarisability (π*), and hydrogen bond donor acidity (α) on the second-order rate constants were investigated and multiple regressions gave much better results with regard to single parameter regressions. Dipolarity/polarisability and hydrogen...
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
Abstract
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...
Systems designed with an ionic liquid and molecular solvents to investigate the kinetics of an SNAr reaction
, Article Progress in Reaction Kinetics and Mechanism ; Volume 38, Issue 2 , 2013 , Pages 157-170 ; 14686783 (ISSN) ; Hallett, J. P ; Padervand, M ; Gholami, M. R ; Sharif University of Technology
2013
Abstract
The microscopic features of binary solvent systems formed by molecular solvents (methanol, ethanol, 2-methylpropan-2-ol, water, pyridine, acetonitrile, 1-propanol, 2-propanol, dimethylformamide) and the ionic liquid ([bmim]BF 4) as cosolvent were used to select mixed solvents with particular characteristics. Molecular-microscopic solvent parameters corresponding to these binary mixtures were utilised to study the kinetics of the nucleophilic substitution reaction between 2-chloro-3,5-dinitropyridine and aniline to investigate and compare the effects of the solvents on a model chemical reaction. For these mixtures, the solvation behaviour is dominated by both the dipolarity/ polarisability...
Appearance of a new superconducting phase in Gd(Ba2-xPr x)Cu3O7+δ
, Article Physica Status Solidi C: Conferences ; Volume 1, Issue 7 , 2004 , Pages 1879-1882 ; 16101634 (ISSN) ; Akhavan, M ; Sharif University of Technology
2004
Abstract
An unusual hump on the resistivity vs. temperature curve of Gd(Ba 2-xPrx)Cu3O7+δ samples have been observed for particular values of Pr doping. Investigation of the origin of this effect has led to an important result. Based on the Rietveld refinement of the XRD patterns, we have found that the Ba atom substitution at the rare earth site could lead to superconductivity in some parts of the grains at T p ∼ 80-90 K, which appears as a hump on the p(T) curve. Our result is in line with the previously proposed possibility of existence of superconductivity in Pr-123 due to the Ba atom substituted at Pr site. © 2004 WILEY-VCH Verlag GmbH & Co. KOaA, Weinheim
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 , 2011 , Pages 1095-1100 ; 08943230 (ISSN) ; Harifi Mood, A. R ; Gholami, M. R ; Sharif University of Technology
Abstract
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...
Solvent polarity and hydrogen bond effects on nucleophilic substitution reaction of 2-bromo-5-nitrothiophene with piperidine
, Article International Journal of Chemical Kinetics ; Volume 43, Issue 4 , 2011 , Pages 185-190 ; 05388066 (ISSN) ; Rahmati, M ; Gholami, M. R ; Sharif University of Technology
Abstract
The reaction kinetics of 2-bromo-5-nitro thiophene with piperidine was studied in a solvent with a mixture of propan-2-ol with methanol and n-hexane at 25°C. The measured rate coefficients of the reaction demonstrated dramatic variations in propan-2-ol-n-hexane mixtures and mild variations in propan-2-ol-methanol system. The second-order rate coefficients of the reaction, kA, decreased sharply with n-hexane content. The multiparameter correlation of log kA versus molecular-microscopic solvent parameters shows interesting results in these solutions. Linear free energy relationship investigations confirm that polarity has a major effect on the reaction rate and hydrogen bond ability of the...
BF3·SiO2: an efficient reagent system for the one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles
, Article Tetrahedron Letters ; Volume 49, Issue 16 , 2008 , Pages 2575-2577 ; 00404039 (ISSN) ; Mirjalili, B. B. F ; Hashemi, M. M ; Sharif University of Technology
2008
Abstract
Silica-supported boron trifluoride (BF3·SiO2) is an efficient, readily available and reusable catalyst for the synthesis of 1,2,4,5-tetrasubstituted imidazoles using benzil, an aromatic aldehyde and an amine in the presence of ammonium acetate. This one-pot procedure is very simple, affording good to excellent yields. © 2008 Elsevier Ltd. All rights reserved
Investigation of the reaction of allyl(cyclopentadienyl)iron(II) dicarbonyl with iminium salts: Synthesis of ammonium salts of substituted five-membered-ring iron complexes
, Article Organometallics ; Volume 26, Issue 1 , 2007 , Pages 201-203 ; 02767333 (ISSN) ; Ziyaei Halimehjani, A ; Saidi, M. R ; Sharif University of Technology
2007
Abstract
Series of quaternary ammonium salts of substituted five-membered-ring iron complexes were prepared by reaction of allyl(cyclopentadienyl)iron(II) dicarbonyl with iminium salts. Also, reactions of allyl-(cyclopentadienyl) iron(II) dicarbonyl with in situ prepared iminium salts afford the same products in good to excellent isolated yields. © 2007 American Chemical Society
Zirconium(IV) oxide chloride and anhydrous copper(II) sulfate mediated synthesis of 2-substituted benzothiazoles
, Article Heteroatom Chemistry ; Volume 17, Issue 2 , 2006 , Pages 136-141 ; 10427163 (ISSN) ; Ismaili, H ; Rezanejade Bardajee, G ; Sharif University of Technology
2006
Abstract
A simple, fast and efficient benign procedure has been developed for one-pot synthesis of 2-substituted benzothiazoles in the presence of zirconium(IV) oxide chloride octahydrate (ZrOCl2·8H 2O) and anhydrous copper(II) sulfate. The reaction of 2-aminothiophenol with aldehydes and anhydrides was carried out efficiently in solvent-free conditions with or without microwave irradiation, and adducts were produced in good to excellent yields. © 2006 Wiley Periodicals, Inc
Ba@Pr or Pr@Ba in R123 HTSC - To be or not to be SC
, Article Physica Status Solidi (B) Basic Research ; Volume 241, Issue 6 , 2004 , Pages 1242-1250 ; 03701972 (ISSN) ; Sharif University of Technology
2004
Abstract
In spite of the vast amount of experimental and theoretical knowledge accumulated in HTSC, the nature of the interaction driving charge carriers to form Cooper pairs below Tc is still unknown. To elucidate the controversial insulating/SC Pr123, the substitution of Pr at Ba site (Pr@Ba) with Ba at Pr site (Ba@Pr) in R123 is compared and reviewed. This might shed some light on the microscopic origin of HTSC. © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Solvent effects on kinetics of an heteroatomic nucleophilic substitution reaction in ionic liquid and molecular solvents mixtures
, Article Russian Journal of Physical Chemistry A ; Volume 87, Issue 12 , 2013 , Pages 1969-1975 ; 00360244 (ISSN) ; Pedervand, M ; Sadeghzadeh Darabi, F ; Gholami, M. R ; Sharif University of Technology
2013
Abstract
Rate constants, k A, for the aromatic nucleophilic substitution reaction of 2-chloro-3,5-dinitropyridine with aniline were determined in different compositions of 2-propanol mixed with hexane, benzene, and 2-methylpropan-2-ol and 1-ethyl-3-methylimidazolium ethylsulfate ([Emim][EtSO4]) with dimethyl sulfoxide at 25 C. The obtained rate constants of the reaction in pure solvents are in the following order: 2-methylpropan-2-ol > dimethyl sulfoxide > 2-propanol > hexane > benzene > [Emim][EtSO4]. Molecularmicroscopic solvent parameters corresponding to the selected binary mixtures were utilized to study the kinetics of a nucleophilic substitution reaction in order to investigate and compare the...
Solvent polarity and hydrogen bond effects on nucleophilic substitution reaction of 2-bromo-5-nitrothiophene with piperidine
, Article International Journal of Chemical Kinetics ; Volume 43, Issue 4 , April , 2011 , pages 185–190 ; Rahmati, M. (Masoud) ; Gholami, M . R. (Mohammad Reza) ; Sharif University of Technology
Abstract
The reaction kinetics of 2-bromo-5-nitro thiophene with piperidine was studied in a solvent with a mixture of propan-2-ol with methanol and n-hexane at 25°C. The measured rate coefficients of the reaction demonstrated dramatic variations in propan-2-ol–n-hexane mixtures and mild variations in propan-2-ol–methanol system. The second-order rate coefficients of the reaction, kA, decreased sharply with n-hexane content. The multiparameter correlation of log kA versus molecular-microscopic solvent parameters shows interesting results in these solutions. Linear free energy relationship investigations confirm that polarity has a major effect on the reaction rate and hydrogen bond ability of the...
Novel one-pot, three-component synthesis of new 2-alkyl-5-aryl-(1H)- pyrrole-4-ol in water
, Article Journal of Organic Chemistry ; Volume 73, Issue 6 , 2008 , Pages 2090-2095 ; 00223263 (ISSN) ; Jajarmi, P ; Eftekhari Sis, B ; Hashemi, M. M ; Sharif University of Technology
2008
Abstract
(Chemical Equation Presented) New 2-alkyl-5-aryl-(1H)-pyrrole-4-ol derivatives were synthesized via three-component reaction of β-dicarbonyl compounds with arylglyoxals in the presence of ammonium acetate in water at room temperature. © 2008 American Chemical Society
A novel synthesis of some 2-imino-4-thiazolidinone derivatives
, Article Journal of Heterocyclic Chemistry ; Volume 44, Issue 1 , 2007 , Pages 35-38 ; 0022152X (ISSN) ; Hojabri, L ; Sharif University of Technology
HeteroCorporation
2007
Abstract
(Chemical Equation Presented) An efficient and simple route is presented to the synthesis of some iminothiazolidinone derivatives. α-Chloro amide derivatives undergo coupling reaction with isothiocyanate in the presence of a mild base, followed by nucleophilic substitution of chlorine by the sulfur atom of isothiocyanate
Solute-solvent interaction effects on second-order rate constants of reaction between 1-chloro-2,4-dinitrobenzene and aniline in alcohol-water mixtures
, Article International Journal of Chemical Kinetics ; Volume 37, Issue 2 , 2005 , Pages 90-97 ; 05388066 (ISSN) ; Gholami, M. R ; Sharif University of Technology
2005
Abstract
The second-order rate coefficients for aromatic nucleophilic substitution reaction between 1-chloro-2,4-dinitrobenzene and aniline have been measured in aqueous solutions of ethanol and methanol at 25°C. The plots of rate constants versus mole fraction of water show a maximum in all-aqueous solutions. The effect of four empirical solvent parameters including hydrogen bond donor acidity (α), dipolarity/polarizability (π*). normalized polarity (ETN), and solvophobicity (Sp) has been investigated. This investigation has been carried out by means of simple and multiple regression models A dual-parameter equation of log k2 versus Sp and α was obtained in all-aqueous solutions (n = 41, r = 0.962,...
Flux dynamics, superconducting, and normal state properties of Gd(Ba 2-xPrx)Cu3O7+δ
, Article European Physical Journal B ; Volume 42, Issue 3 , 2004 , Pages 321-336 ; 14346028 (ISSN) ; Akhavan, M ; Sharif University of Technology
2004
Abstract
Gd(Ba2-xPrx)Cu3O7+δ single phase polycrystalline samples with 0.0 ≤ x ≤ 1.0 were investigated for structural, electronic and flux dynamics properties. Two-dimensional variable range hopping (VRH) is the dominant conduction mechanism in the normal state of the system. Pr doping strongly localizes the carriers in normal state, and finally causes the suppression of superconductivity. The effect of Pr substitution in 123 structure of HTSC at R or Ba sites is to increase the pseudogap temperature Ts, although, Pr at Ba sites has a stronger effect on the increase of Ts and suppression of superconductivity. The magnetoresistance of the samples have been studied within thermally activated flux creep...
Use of computer-assisted methods for the modeling of the retention time of a variety of volatile organic compounds: A PCA-MLR-ANN approach
, Article Journal of Chemical Information and Computer Sciences ; Volume 44, Issue 4 , 2004 , Pages 1328-1335 ; 00952338 (ISSN) ; Kyani, A ; Sharif University of Technology
2004
Abstract
A hybrid method consisting of principal component analysis (PCA), multiple linear regressions (MLR), and artificial neural network (ANN) was developed to predict the retention time of 149 C3 - C12 volatile organic compounds for a DB-1 stationary phase. PCA and MLR methods were used as feature-selection tools, and a neural network was employed for predicting the retention times. The regression method was also used as a calibration model for calculating the retention time of VOCs and investigating their linear characteristics. The descriptors of the total information index of atomic composition, IAC, Wiener number, W, solvation connectivity index, Xlsol, and number of substituted aromatic...
Nanoparticle supported, magnetically separable manganese porphyrin as an efficient retrievable nanocatalyst in hydrocarbon oxidation reactions
, Article RSC Advances ; Volume 6, Issue 47 , 2016 , Pages 41551-41560 ; 20462069 (ISSN) ; Mortazavi Manesh, A ; Sharif University of Technology
Royal Society of Chemistry
Abstract
A manganese porphyrin, meso-tetrakis(pentafluorophenyl)porphyrinato manganese(iii) acetate, Mn(TPFPP)OAc, was immobilized on silica-coated magnetic Fe3O4 nanoparticles functionalized with 3-aminopropyltriethoxysilane (APTS) through the amino propyl linkage using a grafting process in toluene solvent. This enabled the covalent immobilization of Mn(iii) porphyrin via an aromatic nucleophilic substitution reaction, to afford the Fe3O4@SiO2-NH2@MnPor catalyst. The resulting nanoparticles were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), FT-IR spectroscopy, UV-Vis spectroscopy, elemental analysis (CHN), atomic absorption spectroscopy (AAS), and vibrating...