Organic chemistry
Abdolkarim Zare; Jalal Sanjideh
Abstract
Two highly efficient protocols for the production of bis-coumarins under solvent-free conditions have been introduced. The reaction of 4-hydroxycoumarin (2 eq.) with arylaldehydes (1 eq.) using phthalimide-N-sulfonic acid (PhtSA) or isatin-N-sulfonic acid (IsSA), as solid-acid catalysts, afforded the ...
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Two highly efficient protocols for the production of bis-coumarins under solvent-free conditions have been introduced. The reaction of 4-hydroxycoumarin (2 eq.) with arylaldehydes (1 eq.) using phthalimide-N-sulfonic acid (PhtSA) or isatin-N-sulfonic acid (IsSA), as solid-acid catalysts, afforded the mentioned compounds with good to excellent yields in short times.Briefly, we have introduced two new SO3H-bearing solid-acid catalysts, entitled phthalimide-N-sulfonic acid and isatin-N-sulfonic acid, for the preparation of bis-coumarins. The advantages of the presented protocols include: high effectuality and generality of the catalysts, high to excellent yields, short reaction times, simple synthesis of the catalysts from available and inexpensive starting materials, easy work-up and purification of the products, relatively mild conditions, application of solvent-free technique, and good compliance with the green chemistry protocols.
Analytical chemistry
Fatemeh Sabermahani; Nosrat Madadi Mahani; Neda Pourgholamrezazadeh
Volume 6, Issue 2, pp. 109-217, Serial No. 19 , April 2018, , Pages 148-159
Abstract
In this work, a low-cost activated carbon as well as non-hazardous material, with high adsorption capacity, was prepared from Melia azedarach fruit (MF) by ZnCl2 activation for the removal of Pb(II) toxic metal from aqueous solutions. The microstructure of the activated carbon was observed by Scanning ...
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In this work, a low-cost activated carbon as well as non-hazardous material, with high adsorption capacity, was prepared from Melia azedarach fruit (MF) by ZnCl2 activation for the removal of Pb(II) toxic metal from aqueous solutions. The microstructure of the activated carbon was observed by Scanning Electron Microscopy (SEM). Batch experiments have been performed as a function of pH, contact time, dose of sorbent, initial Pb(II) concentration, temperature and strength ionic. It was found that the adsorption process was very quick and the equilibrium attained within 10 min. The maximum adsorption capacity for Pb(II) using Langmuir isotherm was 111.11 mg g-1. Thermodynamic study indicated that the Pb(II) adsorption was feasible, spontaneous, and endothermic. The results show that the produced activated carbon from Melia azedarach fruit is an efficient and cost-effective adsorbent for removing Pb(II).
Organic chemistry
Vinod Kamble; Munazza Sadaf; Bushra Saleh
Volume 5, Issue 2, pp. 121-236, Serial No. 15 , April 2017, , Pages 167-172
Abstract
Multi-component coupling reaction (MCR) is a powerful synthetic tool for the synthesis of biologically active compounds. Development of such multi-component coupling reaction strategies in visible light has been of considerable interest, as they provide simple and rapid access to a large number of organic ...
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Multi-component coupling reaction (MCR) is a powerful synthetic tool for the synthesis of biologically active compounds. Development of such multi-component coupling reaction strategies in visible light has been of considerable interest, as they provide simple and rapid access to a large number of organic molecules through a sustainable path. An efficient and green protocol for the synthesis of tetrahydrobenzo[b]pyrans derivatives by one-pot, three component coupling reaction of aromatic aldehyde, malononitrile, and dimedone has been developed using readily available cesium carbonate as the catalyst under visible light. This efficient procedure has the advantages of giving the target compounds in high yields, short reaction times, simple work-up procedure, use of chief and easily available catalyst, and environmentally benign conditions.
Organic chemistry
Rahmatollah Rahimi; Fatemeh Fayyaz; Mehdi Rassa; Mahboubeh Rabbani
Volume 4, Issue 2, pp. 133-235, Serial No. 11 , April 2016, , Pages 175-185
Abstract
In this study, 5,10,15,20-tetrakis(4-nitrophenyl)porphyrin (TNPP) and its zinc porphyrin complex (ZnTNPP) were synthesized in situ using the microwave method and identified by UV-Vis, FT-IR and 1H NMR. The photostability and photodynamic antimicrobial activity (PACT) of these compounds were investigated ...
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In this study, 5,10,15,20-tetrakis(4-nitrophenyl)porphyrin (TNPP) and its zinc porphyrin complex (ZnTNPP) were synthesized in situ using the microwave method and identified by UV-Vis, FT-IR and 1H NMR. The photostability and photodynamic antimicrobial activity (PACT) of these compounds were investigated on Pseudomonas aeruginosa and Bacillus subtilis under visible light irradiation. MIC, MBC and inhibition zones produced by these compounds were determined and the number of bacteria counted. The results indicated that both compounds have significant stability when illuminated for various illumination periods in nutrient broth media. Both compounds exhibited more effective activity against P. aeruginosa than B. subtilis in nutrient agar.
Applied Chemistry
Hossein Hosseinzadeh; Mojtaba Abbasian; Shadi Hassanzadeh
Volume 2, Issue 3, pp. 162-231, Serial No. 4 , July 2014, , Pages 196-208
Abstract
A novel pH-responsive superabsorbent hydrogel based on gelatin was prepared through crosslinking copolymerization of poly (acrylic acid) and poly (itaconic acid). The copolymerization conditions including monomers, initiator, gelatin and crosslinker concentration, reaction temperature, and neutralization ...
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A novel pH-responsive superabsorbent hydrogel based on gelatin was prepared through crosslinking copolymerization of poly (acrylic acid) and poly (itaconic acid). The copolymerization conditions including monomers, initiator, gelatin and crosslinker concentration, reaction temperature, and neutralization percent were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. The hydrogels structure was confirmed using Fourier-transform infrared, thermogravimetric analysis, differential scanning calorimetric and scanning electron microscopy. The swelling of the superabsorbing hydrogel was examined in buffer solutions with pH ranged 3-12. Moreover, the swelling of the hydrogel was conducted in 0.15 M aqueous solutions of NaCl, CaCl2, and AlCl3. Due to the high swelling capacity in salt solutions, the hydrogel may be referred to as "low-salt sensitive" superabsorbent.
Organic chemistry
Mohammad Reza Asaadi; Hosein Behmadi; Abdolhossein Massoudi; Mohammad Shaker
Abstract
Pyrene and its derivatives exhibit thermal stability, high extinction coefficients, excimer formation, high photoluminescence, long fluorescence lifetime, fluorophoric properties and enhanced charge carrier mobility which make them find applications in optoelectronic area and are useful as large planar ...
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Pyrene and its derivatives exhibit thermal stability, high extinction coefficients, excimer formation, high photoluminescence, long fluorescence lifetime, fluorophoric properties and enhanced charge carrier mobility which make them find applications in optoelectronic area and are useful as large planar synthetic building blocks in supramolecular chemistry. One of the approaches to overcome this downside is the introduction of bulky aryl/alkyl substituents or incorporation heteroatoms into the π-extended conjugated system of pyrene. In this work, Some new derivatives of 4-Aryl-2, 6-di(pyren-1-yl)pyridines have been synthesized through one-pot reaction and were formed with cyclization of Arylaldehydes, 1-acetylpyrene and ammonium acetate in acetic acid. The products were confirmed by FT-IR, Mass, 1H-NMR, 13C-NMR and elemental analysis. These new compounds were subsequently studied for their fluorescence properties.
Organic chemistry
Mahnaz Saraei; Gholamreza Zarrini; Parisa Rajabpour
Volume 6, Issue 3, pp. 218-324, Serial No. 20 , July 2018, , Pages 271-279
Abstract
A novel acrylate monomer containing 4H-pyran-4-one and 1,2,3-triazole ring, {1-[4-(4-oxo-6-phenyl-4H-pyran-2-yl)benzyl]-1,2,3-triazol-4-yl}methyl acrylate was synthesized by the reaction of 2-{4-[(4-(hydroxymethyl)-1,2,3-triazol-1-yl)methyl]phenyl}-6-phenyl-4H-pyran-4-one with acryloyl chloride in the ...
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A novel acrylate monomer containing 4H-pyran-4-one and 1,2,3-triazole ring, {1-[4-(4-oxo-6-phenyl-4H-pyran-2-yl)benzyl]-1,2,3-triazol-4-yl}methyl acrylate was synthesized by the reaction of 2-{4-[(4-(hydroxymethyl)-1,2,3-triazol-1-yl)methyl]phenyl}-6-phenyl-4H-pyran-4-one with acryloyl chloride in the presence of triethylamine. The structure of the acrylate monomer was established on the basis of FT-IR, 1H NMR, 13C NMR, MS and elemental analysis. This monomer was polymerized using 2,2´-azobisisobutyronitrile (AIBN) as the initiator in N,N-dimethylformamide solution. Thermal stability of the polymer was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The synthesized compounds were evaluated for their antibacterial activity against Gram-positive and Gram-negative bacteria using the disk diffusion method. The results of antibacterial assay indicated that these compounds exhibited moderate bactericidal activity.
Organic chemistry
Ali Saberi; Mehri Alimohammadi
Volume 5, Issue 3, pp. 237-363, Serial No. 16 , July 2017, , Pages 278-285
Abstract
Usage of herbal medicine has been under so much attention for many years. They are gradually replacing synthetic drugs in pharmaceutical fields due to their fewer side effects. Nowadays, essential oils are widely used for the treatment of diseases as well as being applied as pesticide. In this study, ...
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Usage of herbal medicine has been under so much attention for many years. They are gradually replacing synthetic drugs in pharmaceutical fields due to their fewer side effects. Nowadays, essential oils are widely used for the treatment of diseases as well as being applied as pesticide. In this study, 32 components of Zingiber essential oil were identified representing 97.42% of the extracted oil by Gas chromatography-mass spectrometry (GC/MS). Antioxidant activity of the extracted oil were evaluated. In this experiment the effect of Zingiber essential oil on oxidation temperature of oleic acid was investigated by using a diffential scanning calorimetric (DSC) instrument.
Analytical chemistry
Hadi Noorizadeh; Sharmin Esmaeilpoor; Zohreh Moghadam; Shahnaz Nosratolahy
Volume 2, Issue 4, pp. 236-325, Serial No. 5 , October 2014, , Pages 283-299
Abstract
The veterinary drugs residues are also important pollutants found in milk, since veterinary drugs are commonly used in cattle management. Considering the role of milk in human nutrition and its wide consumption throughout the world, it is very important to ensure the milk quality. A quantitative structure–retention ...
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The veterinary drugs residues are also important pollutants found in milk, since veterinary drugs are commonly used in cattle management. Considering the role of milk in human nutrition and its wide consumption throughout the world, it is very important to ensure the milk quality. A quantitative structure–retention relationship (QSRR) was developed using the partial least square (PLS), Kernel PLS (KPLS) and Levenberg-Marquardt artificial neural network (L-M ANN) approach for chemometrics study. Genetic algorithm was employed as a factor selection procedure for PLS and KPLS modeling methods. By comparing the results, GA-KPLS descriptors are selected for L-M ANN. Finally a model with a low prediction error and a good correlation coefficient was obtained by L-M ANN. This is the first research on the QSRR of veterinary drugs using the chemometrics models.
Organic chemistry
Batol Zakerinasab; Mohammad Ali Nasseri; Fateme Kamali
Volume 3, Issue 4, pp. 283-387, Serial No. 9 , October 2015, , Pages 335-347
Abstract
Quinolines, an important class of potentially bioactive compounds, have been synthesized by treatment of O-aminoarylketones and carbonyl compounds utilizing niobium (V) chloride / polyethylenglycole(NbCl5.PEG) and niobium(V)chloride (NbCl5) as available and inexpensive catalysts. The quinoline derivatives ...
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Quinolines, an important class of potentially bioactive compounds, have been synthesized by treatment of O-aminoarylketones and carbonyl compounds utilizing niobium (V) chloride / polyethylenglycole(NbCl5.PEG) and niobium(V)chloride (NbCl5) as available and inexpensive catalysts. The quinoline derivatives were prepared in glycerol, an excellent solvent in terms of environmental impact, with high yields (76-98%) and short reaction times (15- 90 min). Not only diketones but also ketones afforded the desired products in good to excellent yields. The reaction time of 2-amino-5-chlorobenzophenone and dicarbonyl compounds was longer than those of 2-aminobenzophenone. The reaction of cyclic diketones took place faster than open chain analogues. These reactions also proceeded with acetophenone derivatives. In these cases the reaction times are longer.
Nanochemistry
Sandip P. Patil; Vilas K. Mahajan; Gunvant H. Sonawane; Vinod S. Shrivastava
Volume 5, Issue 4, pp. 364-493, Serial No. 17 , October 2017, , Pages 417-428
Abstract
The present study reports, the synthesis of ZnO-bentonite nanocomposite by the incorporation of ZnO with bentonite clay. The nanocomposite was characterised by XRD and SEM. ZnO-bentonite was effectively used for removal of Methylene Blue (MB). Removal of MB takes place by photocatalytic degradation and ...
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The present study reports, the synthesis of ZnO-bentonite nanocomposite by the incorporation of ZnO with bentonite clay. The nanocomposite was characterised by XRD and SEM. ZnO-bentonite was effectively used for removal of Methylene Blue (MB). Removal of MB takes place by photocatalytic degradation and adsorption. Photocatalytic degradation of MB occurs by advanced oxidation process. The factors affecting photocatalytic degradation like pH, initial dye concentration, contact time and photocatalyst dose are investigated. Optimum pH was 8 and contact time was 80 min for photocatalytic degradation of MB. The kinetic study shows that adsorption follows pseudo-second-order kinetics. Adsorption was also described by Langmuir and Freundlich isotherms. Adsorption isotherm found to follow Langmuir isotherm. The monolayer coverage capacity was observed to be 62.5 mg/g. The amount of dye adsorbed was 252.7 mg/g for 0.2 g/L photocatalyst dose at 60mg/L MB concentration.
Physical chemistry
Venugopal Rajendran; Varathan Selvaraj; Pachaiyappan Abimannan
Volume 6, Issue 1, pp. 1-108, Serial No. 18 , January 2018, , Pages 55-61
Abstract
The present work describes, the reaction between disodium salt of 1,3-dihydroxybenzene (in situ formation) and propargyl bromide was carried out in a solid-liquid biphasic phase transfer catalytic system at 50°C. Higher selectivity of the bis-derivative (1,3-bis(prop-2-ynyloxy)benzene) was obtained ...
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The present work describes, the reaction between disodium salt of 1,3-dihydroxybenzene (in situ formation) and propargyl bromide was carried out in a solid-liquid biphasic phase transfer catalytic system at 50°C. Higher selectivity of the bis-derivative (1,3-bis(prop-2-ynyloxy)benzene) was obtained under solid-liquid PTC condion. The conversion of propargyl bromide of more than 99% was achieved in the presence of tetra-n-butylammonium bromide (TBAB) as catalyst. From the experimental evidence there is no mono-dervative observed. Experiments were conducted to increase the conversion of propargyl bromide such as, stirring speed, various PTCs, temperature, various solvents and amount of TBAB loading. All the experiments were conducted to obey pseudo-first order rate law. Apparent activation energy was also determined from the Arrhenius plot.
Nanochemistry
Sharmin Esmaeilpoor; Zahra Shirzadi; Hadi noorizadeh
Volume 2, Issue 1, pp. 1-81, Serial No. 2 , January 2014, , Pages 56-71
Abstract
The quantitative structure-retention relationship (QSRR) of nanoparticles in roadside atmosphere against the comprehensive two-dimensional gas chromatography which was coupled to high-resolution time-of-flight mass spectrometry was studied. The genetic algorithm (GA) was employed to select the variables ...
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The quantitative structure-retention relationship (QSRR) of nanoparticles in roadside atmosphere against the comprehensive two-dimensional gas chromatography which was coupled to high-resolution time-of-flight mass spectrometry was studied. The genetic algorithm (GA) was employed to select the variables that resulted in the best-fitted models. After the variables were selected, the linear multivariate regressions [e.g. the partial least squares (PLS)] as well as the nonlinear regressions [e.g. the kernel PLS (KPLS) and Levenberg- Marquardt artificial neural network (L-M ANN)] were utilized to construct the linear and nonlinear QSRR models. The correlation coefficient cross validation (Q2) and relative error for test set L-M ANN model are 0.939 and 4.89, respectively. The resulting data indicated that L-M ANN could be used as a powerful modeling tool for the QSPR studies.
Organic chemistry
Mohammad Javad Taghizadeh; Khosrow Jadidi
Volume 3, Issue 1, pp. 1-71, Serial No.6 , January 2015, , Pages 57-61
Abstract
An efficient one-pot three-component procedure for the synthesis of new chiral spiro oxindolopyrrolidines/pyrrolizidines with highly regio- and diastereo-enantio, selective from 1,3-dipolar cycloaddition of azomethine ylides and chiral menthol-drived trans-cinnamic are described. The mechanism of the ...
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An efficient one-pot three-component procedure for the synthesis of new chiral spiro oxindolopyrrolidines/pyrrolizidines with highly regio- and diastereo-enantio, selective from 1,3-dipolar cycloaddition of azomethine ylides and chiral menthol-drived trans-cinnamic are described. The mechanism of the reaction is discussed on basis of the assignment of the absolute configuration of one of the cycloaddition products, which obtained by single crystal X-ray analysis. The process occurs at reflux temperature in ethanol as green solvent and in the absence of any bidentate chelating Lewis acids. Functionalized pyrrolidines and pyrrolizidines with spirooxindole ring systems are the central skeletons for numerous alkaloids and pharmacologically important compounds.1 Gelesmine, pseudotabersonine, formosanine, isoformosanine, morroniside and mitraphylline are some of the alkaloids containing spirooxindole ring systems.
Organic chemistry
Nader Noroozi Pesyan; Vali Gholsanamloo; Maryam Moradi Par; Hamid Rashidnejad; Ali Gharib; Kamelia Nejati
Abstract
Four new azo-dyes, 3-phenyl azopentane-2,4-dion (LA), 3-(4-nitro phenyl azo)-pentane-2,4-dion (LP), 3-(2-nitro phenyl azo)-pentane-2,4-dion (LO) and 4-(1-acetyle-2-oxo-propyl azo)-benzene sulfonate sodium (LS), were synthesized from, aniline, 4-nitroaniline, 2-nitroaniline and sulfanilic acid with acetylacetone, ...
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Four new azo-dyes, 3-phenyl azopentane-2,4-dion (LA), 3-(4-nitro phenyl azo)-pentane-2,4-dion (LP), 3-(2-nitro phenyl azo)-pentane-2,4-dion (LO) and 4-(1-acetyle-2-oxo-propyl azo)-benzene sulfonate sodium (LS), were synthesized from, aniline, 4-nitroaniline, 2-nitroaniline and sulfanilic acid with acetylacetone, respectively. Reaction of these new dyes with acetate salts of copper(II), nickel(II) and cobalt(II) in molar ratios of 1:2 were carried out to produce azo metal (II) complexes with the general stoichiometry; CuL2, CoL2 and NiL3 in complexes. Structure of azo dyes was characterized using FT-IR,1H NMR,13C NMR, UV-Visible and also the corresponding metal (II) complex were characterized by FT IR, UV-Visible and CHN and XRD analysis techniques. Elemental analysis and spectral data indicated that the dye as a ligand with two teeth, N and O, acts as a bidentate ligand. Differences in absorption maxima of azo ligands compared to those corresponding complexes were also studied. Also, in this work, singular value decomposition (SVD) as a chemometric method was used to determine the Cu(II), Co(II) and Ni(II) complexes with the mentioned ligands in methanol by UV-Vis spectrophotometry. SVD method confirmed the formation of CuL2, CoL2 and NiL3 complexes.
Physical chemistry
Vahid Moeini; Seyed Hojatollah Rahimi; Zohre Rakhsha
Volume 4, Issue 1, pp. 1-132, Serial No. 10 , January 2016, , Pages 78-93
Abstract
In this work, we report results of calculations based on the density functional theory of different species metal-ozone, containing mercury, silver and gold. The chosen species range from small molecules and large transition-metal containing ozone with mercury, silver and gold complexes. A comparative ...
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In this work, we report results of calculations based on the density functional theory of different species metal-ozone, containing mercury, silver and gold. The chosen species range from small molecules and large transition-metal containing ozone with mercury, silver and gold complexes. A comparative analysis of the description of the metal-oxygen bond obtained by different methodologies is presented. The topology of the electronic density of the metal-ozone is studied, at DFT level, using the theory of atoms in molecules (AIM) developed by Bader. Thermodynamic variables of reactions have been calculated. The effect of temperature on thermodynamics quantities of the reaction has also been investigated. The LanL2MB basis set for mercury, silver and gold with ozone are used at the B3LYP method. The energy levels of the HOMO and LUMO orbitals compute at the B3LYP/LanL2MB level.
Organic chemistry
Vahid Azizkhani; Ali Ramazani; Sang Woo Joo
Volume 3, Issue 2, pp. 72-147, Serial No. 7 , April 2015, , Pages 121-131
Abstract
Simple, cheap and green protocol for effective conversion of alcohols to corresponding carbonyl compounds in the presence of H14[NaP5W30O110] and ammonium nitrate is reported. The products were characterized by FT-IR and comparison of their physical properties with those reported in the literatures. ...
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Simple, cheap and green protocol for effective conversion of alcohols to corresponding carbonyl compounds in the presence of H14[NaP5W30O110] and ammonium nitrate is reported. The products were characterized by FT-IR and comparison of their physical properties with those reported in the literatures. The progress of the reaction was monitored by thin layer chromatography (TLC) technique. The aliphatic products were detected by gas chromatography–flame ionization detector. Reactions were completed within 15-35 minutes at room temperature. In order to investigate the catalyst reusability, the oxidation of benzyl alcohol was carried out in the presence of H14[NaP5W30O110]. At the end of each reaction, the catalyst was separated and the recovered catalyst was reused for at least three runs without significant degradation in catalytic activity and performance.
Organic chemistry
Milad Edraki; Issa Mousazadeh Moghadam; Mohammad Banimahd Keivani; Mohammad Hossein Fekri
Abstract
Corrosion inhibitory impacts of turmeric with concentrations of 200-800 ppm on the electrochemical behavior of mild steel were studied in the medium of NaCl 3.5% using several techniques such as electrochemical impedance spectroscopy (EIS) and polarization. Scanning electron microscopy (SEM) was used ...
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Corrosion inhibitory impacts of turmeric with concentrations of 200-800 ppm on the electrochemical behavior of mild steel were studied in the medium of NaCl 3.5% using several techniques such as electrochemical impedance spectroscopy (EIS) and polarization. Scanning electron microscopy (SEM) was used for analyzing the surface of mild steel after 24 hours of immersion in the electrolyte solution, with and without turmeric. The results of polarization and EIS demonstrated that for the steel sample immersed in a salt solution containing 800 ppm of turmeric extract, the corrosion current density was decreased and the corrosion potential was shifted to positive values. On the other hand, the electric capacitance of the double-layer was decreased and the charge transfer resistance and inhibition efficiency were increased, confirming an improved corrosion resistance compared to the other sample concentrations. SEM results for the mentioned inhibitor with 800 ppm concentration showed a more even and continuous film formed on the surface of mild steel and no corrosion products was observed.
Physical chemistry
Reza Behjatmanesh; Negin Safaeian
Volume 2, Issue 2, pp. 82-163, Serial No. 3 , April 2014, , Pages 147-156
Abstract
: In this work, different levels of theory containing HF, B3LYP, and MP2 with different basis sets such as 6-31G, 6-31G*, 6-311G, 6-311+G, 6-31+G*, 6-31+G are used to predict relative acidity constants of some aniline derivatives. Three different kinds of radii containing UAHF, Bondi, and Pauling are ...
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: In this work, different levels of theory containing HF, B3LYP, and MP2 with different basis sets such as 6-31G, 6-31G*, 6-311G, 6-311+G, 6-31+G*, 6-31+G are used to predict relative acidity constants of some aniline derivatives. Three different kinds of radii containing UAHF, Bondi, and Pauling are used to study how cavity forms change acidity constants. In all cases, DPCM model is used to simulate solvation Gibbs free energy. Furthermore, one similar level and basis set has been linked to IEFPCM and DPCM models to compare the results. To relate gas-phase Gibbs free energy to the solution Gibbs free energy, a simple thermodynamic cycle is used. Results show that quantum chemical calculations are robust techniques for estimating acidity constants.
Applied Chemistry
Liu Jiesheng; Li Faping; Xing Shanshan; He Xiang
Volume 6, Issue 2, pp. 109-217, Serial No. 19 , April 2018, , Pages 160-168
Abstract
In this study, the interaction between the silica filler and polydimethylsiloxanes (PDMS) was investigated from the aspects of the bound rubber and morphological characterization. With special attention to the dynamic properties, the dynamic test was conducted by dynamic shear rheometer. The results ...
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In this study, the interaction between the silica filler and polydimethylsiloxanes (PDMS) was investigated from the aspects of the bound rubber and morphological characterization. With special attention to the dynamic properties, the dynamic test was conducted by dynamic shear rheometer. The results show that the modified fillers disperse uniformly within PDMS matrix without aggregation and connect closely with the matrix than that of the unmodified fillers. Surface modification of filler increases the bound rubber content. The increase in silica loading leads to an increase in the silica-silica interaction and a decrease in filler-rubber interaction, which results in the aggregation of fillers and the increase of the bound rubber content. It was apparent that storage modulus, loss modulus and tanδ of unvulcanized PDMS/filler compounds filled with treated silica filler were lower than that of the untreated silica system. Moreover, the tanδ decreases with increasing silica loading.
Nanochemistry
Professor Mohammad Ali Karimi; Malihe Alsadat Mozaheb; Abdolhamid Hatefi-Mehrjardi; Hossein Tavallali; Abdol Mohammad Attaran
Volume 5, Issue 2, pp. 121-236, Serial No. 15 , April 2017, , Pages 173-185
Abstract
In this paper, multivariate calibration methods of partial least squares (PLS) and principle component regression (PCR) were investigated in simultaneously determination of hydrazine (HZ) and acetylhydrazine (AHZ). The aforementioned methods are based on formation of the silver nanoparticles (AgNPs) ...
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In this paper, multivariate calibration methods of partial least squares (PLS) and principle component regression (PCR) were investigated in simultaneously determination of hydrazine (HZ) and acetylhydrazine (AHZ). The aforementioned methods are based on formation of the silver nanoparticles (AgNPs) from the reaction of HZ and AHZ with Ag+ ions as oxidizing agent in the presence of citrate ions as a stabilizing and catalyzing agent. The reaction was followed by analytical wavelength (420 nm) corresponding to the maximum extinction of was related to surface plasmon resonance (SPR) of AgNPs. These methods were based on the differences observed in the production rate of AgNPs. Differences in the kinetic behavior of the HZ and AHZ were exploited using PLS and PCR to resolve concentration of analytes in their mixture. The obtained results show that simultaneous determination of HZ and AHZ can be performed in the concentration linear ranges of 40.0-1000.0 and 200.0-1000.0 ng mL-1, respectively. The root mean squares errors of prediction (RMSEP) for applying PCR and PLS methods to 9 synthetic samples in these concentration ranges were 0.8307 and 1.9411 for HZ and 1.4407 and 0.9883 for AHZ, respectively. To assess selectivity of the methods, the effects of certain foreign ions upon the reaction rate were determined. Both methods (PLS and PCR) were validated using a set of synthetic sample mixtures and then they were applied for simultaneous determination of HZ and AHZ in different water samples.
Organic chemistry
Vinod Kamble; Sandeep Atkore; Parshuram Pisal; Munazza Sadaf; Renuka V. Thakre
Volume 4, Issue 2, pp. 133-235, Serial No. 11 , April 2016, , Pages 186-197
Abstract
The highly substituted pyridine derivatives are found to exhibit diverse pharmacological activities. They are also emerged as potential medicinal leads in developing therapeutic agents for the treatment of various diseases. In this work, a series of 2-amino-3,5-dicarbonitrile-6-thio-pyridine derivatives ...
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The highly substituted pyridine derivatives are found to exhibit diverse pharmacological activities. They are also emerged as potential medicinal leads in developing therapeutic agents for the treatment of various diseases. In this work, a series of 2-amino-3,5-dicarbonitrile-6-thio-pyridine derivatives have been synthesized at room temperature via one-pot, multi-component reaction of various aromatic aldehydes, malononitrile and thiophenols using catalytic amount of tetrabutylammonium bromide (TBAB) and cesium carbonate in methanol. In the present method, the use of thermal condition is avoided. In addition, the advantages such as operational simplicity, economic viability, ecologically benign nature make this protocol a very efficient alternative to the literature methods.
Nanochemistry
Mahdi Rezaei Sameti; Nina Alisafarzadeh
Volume 2, Issue 3, pp. 162-231, Serial No. 4 , July 2014, , Pages 209-221
Abstract
The aim of this research is studying the effects of Ge-doped on CO adsorption on the outer and inner surfaces of (6, 0) zigzag model of boron nitride nanotube (BNNTs) by using DFT theory. For this purpose, eight models of CO adsorption on the surfaces of BNNTs are considered. At first step, all structures ...
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The aim of this research is studying the effects of Ge-doped on CO adsorption on the outer and inner surfaces of (6, 0) zigzag model of boron nitride nanotube (BNNTs) by using DFT theory. For this purpose, eight models of CO adsorption on the surfaces of BNNTs are considered. At first step, all structures were optimized at B3LYP and 6-31G (d) standard base set and then the electronic structure, adsorption energy, HOMO - LUMO orbitals, gap energy, quantum molecular descriptors, and NQR parameters were determined. The bond lengths neighborhood sites of Ge-doped of BNNTs at all models were increased and the bond angles decreased. The small adsorption energy value and large interaction distance show that the adsorption of CO on BNNTs is weakly physical adsorption due to weak Van der Waals interaction. Our calculated results show that the adsorption of CO on the surface of undoped models is more favorable than Ge-doped models. The NQR parameters of the first layer in all the models are larger than those other layers.
Nanochemistry
Roya Ahmadi; Mohammad Reza Jalali Sarvestani
Abstract
In this study, the performance of fullerene (C20) and boron nitride cage (B12N12) as a sensing material for detection of proline was evaluated by density functional theory. For this purpose, the structures of proline, C20, B12N12 and the derived products from the proline adsorption on the surface of ...
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In this study, the performance of fullerene (C20) and boron nitride cage (B12N12) as a sensing material for detection of proline was evaluated by density functional theory. For this purpose, the structures of proline, C20, B12N12 and the derived products from the proline adsorption on the surface of nanostructures were optimized geometrically. Then, IR and Frontier molecular orbital calculations were performed on them. The obtained adsorption energies, enthalpy changes (ΔHad) and Gibbs free energy variations (ΔGad) demonstrate that proline adsorption on the surface of the boron nitride cage is exothermic, spontaneous and experimentally feasible. Whilst, the proline interaction with C20 is endothermic, non-spontaneous and experimentally impossible. The effect of temperature on the adsorption process was also checked out and the results reveal that 298 K is the best temperature for the adsorption procedure. The Calculated specific heat capacity values show that boron nitride cage can be utilized as a sensing material in the construction of thermal biosensors for proline determination. The calculated molecular orbital parameters indicate that B12N12 could be used as a neutral ion carrier and also an electroactive sensing material in the development of potentiometric and conductometric biosensors. All of the calculations were implemented by density functional theory method and B3LYP/6-31G(d) basis set.
Physical chemistry
Mahdi Rezaei Sameti; Fateme Ataeifar
Volume 6, Issue 3, pp. 218-324, Serial No. 20 , July 2018, , Pages 280-292
Abstract
In this research, the effects of HCN adsorption on the surface of the pristine, Ge, P, and GeP doped boron nitride nanotube (BNNTs) are investigated by using density function theory at the B3LYP/6–31G(d, p) level of theory. At the first step, we consider different configurations for adsorbing HCN ...
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In this research, the effects of HCN adsorption on the surface of the pristine, Ge, P, and GeP doped boron nitride nanotube (BNNTs) are investigated by using density function theory at the B3LYP/6–31G(d, p) level of theory. At the first step, we consider different configurations for adsorbing HCN molecule on the surface of BNNTs. The optimized models are used to calculate the structural, electrical, NQR parameters and quantum descriptors such as global hardness, global softness, electrophilicity, gap energy, Fermi level energy, electronic chemical potential, and electronegativity of BNNTs/HCN complex. Inspection of results demonstrates that with doping Ge impurity the sensivity of BNNTs for adsorbing HCN molecule increase significantly from original values. The adsorption of HCN molecule on the surface of Ge-doped is more stable and favourable than other those models. With adsorbing of HCN gas and doping of Ge and GeP the NQR, quantum molecular descriptors and molecular orbital energies of the nanotube alter significantly from original state. On the other hand the electrophilicity index of E model is more than those other models.