فهرست مطالب

  • Volume:4 Issue: 3, May-Jun 2020
  • تاریخ انتشار: 1398/12/24
  • تعداد عناوین: 12
  • Elham Sheikh Ansari, Reza Ghiasi *, Ali Forghaniha Pages 220-233
    In this work, density functional theory (DFT) method was employed at the M062X/6–311G (d,p) level of theory to investigate the Diels-Alder reaction of isobenzofuran and ethylene in the gas and solution phases theoretically. To perform the computations in the solution phase, the polarizable continuum model (PCM) was applied. It was evaluated how the solvent affects the barrier height (DE‡) and thermodynamic parameters (DG‡ and DH‡) in this reaction. The dependency of these parameters on the Onsager function was discussed. The polar character of the reaction was measured through the global electron density transfer (GEDT). The Wiberg bond indices were used to assess the progress of the reactions, and the synchronicity values of the reactions were determined. Results revealed that, the barrier energy values of the reaction increased in solution phase compared to gas phase. GEDT values were lower than 0.15 e and activation barrier higher than 18 kcal/mol in the gas and solution phases. Therefore, this reaction was considered as a non-polar DA reaction.
    Keywords: isobenzofuran, Diels-Alder reaction, global electron density transfer (GEDT), Reaction mechanism, transition state structure, Wiberg bond index
  • Fatemeh Hakimi *, Mehdi Fallah Mehrjardi, Elham Golrasan Pages 234-244

    Yttrium aluminum garnet (YAG) was used to efficiently catalyzed andas an eco-friendly method and efficient catalyst for the synthesis of benzimidazole and benzoxazole derivatives by through the one-pot cyclocondensation of various aldehydes with o-phenylenediamines and o-aminophenol in ethanol at 70 °C. The present method revealed several advantages such as high yields, easy purification, mild reaction conditions, easy work-up, and short reaction times. Also, the nanoparticles (YAG) were found to be easily synthesized, cheap, air and moisture stable, heterogenic, and green catalyst.

    Keywords: Yttrium aluminum garnet, Benzimidazole, Benzoxazole, o-Phenylenediamines, o-aminophenol, Aldehydes
  • Amir Samimi, Soroush Zarinabadi *, Amir Hossein Shahbazi Kootenaei, Alireza Azimi, Masoumeh Mirzaei Pages 245-257

    Naphtha catalytic reforming is one of the main processes of gasoline production with high octane number. Inactive catalysts and changing the products distribution is an important issue in this process. In this paper we discussed the kinetic overview of catalytic reforming units (fixed and continuous reforming). The catalyst activity model introduced in this research study has been used as a function of temperature and process time to detect the catalyst deactivation. The kinetic model and catalyst activity were estimated by using the genetic algorithm as well as overlapping the proposed model results with the experimental data. The results of the modeling showed that the amount of the aromatics during the reactor reduced the trend due to the decrease in the amount of paraffin and naphthen. After the process modeling, the effect of different factors such as time, reactor temperature changes, reactors operating pressure, and the ratio of hydrogen to hydrocarbon on the activity of catalysts and distribution of the products were investigated. The results revealed that, the aromatics rate decreased and coke formed rate on the catalyst surface increased by catalyst activity passing time. Also, increasing the input temperature and reducing the ratio of hydrogen to hydrocarbon enhanced the aromatics produced rate.

    Keywords: Catalytic reforming, Naphtha, Kinetic investigation, Activity
  • Shahab Khameneh Asl *, Behnam Mohammadi, Alireza Khataee Pages 258-275
    Titania nanotube arrays are of great interest due to their nanotubular structure and size-dependent properties. Self-organized TiO2 nanotube arrays could be simply synthesized using anodization method. Many researchers had synthesized TiO2 nanotube arrays with various pore-sizes and lengths through changing the electrolyte type and concentration, pH, applied voltage, and electrolyte composition. Despite the relatively large bandgap of TiO2 (3.2 eV), rapid recombination of electron hole generated during photocatalytic reaction has limited the efficiency of the photocatalytic reactions under the visible light. Many researchers have been conducted to improve the photocatalytic efficiency of the TiO2 nanotube arrays by doping with metal and nonmetal ions. In this work, TiO2 nanotubes were synthesized using the anodization in the variety conditions such as electrolyte concentration, anodization voltage, and time. The photoreactivity of the TiO2 nanotube before and after doping was investigated. The morphology, microstructure, photo micro kinetics and photo absorption of the doped–TiO2 nanotube were characterized using SEM/EDX, XRD, and UV–Vis spectrum. The decolorization of C.I. acid red 14 dye (AR 14) by Photocatalytical process based on TNT films was calculated in a batch type photoreactor. Response surface methodology (RSM) was used to recognize single and multi-effects of the main independent parameters (anodizing time, anodizing voltage, N2 treatment time, and catalyst surface area) on the decomposition rate. A central composite design (CCD) was used to maximize the photoreaction of AR 14 efficacy. A second-order empirical relationship between the response and independent variables was extracted. The results of the analysis of variance (ANOVA) demonstrated a high coefficient of determination value (R2=0.980). Optimum decolorization rate was calculated and experimentally conformed. The optimum anodizing time, anodizing voltage, N2 treatment time, and catalyst surface area were found to be 200 s, 20 V, 2077 h and 5 cm2, respectively. Under the optimal estimated conditions, the highest bleaching efficiency of AR 14 (>99%) was obtained at the lowest reaction time. The results clearly proved that, the response surface methodology could be the suitable method to optimize and scale up the photo catalytically conditions in lab and industrial cases. Also, graphical 2-3 D plots were employed to obtain the optimum point and continuous response.
    Keywords: TiO2 nano tubes, Experimental Design, Response Surface Methodology, anodizing conditions, Photocatalysis
  • Rouhollah Haji Abdolvahab *, Mohammad Reza Zamani Meymian, Noura Soudmand Pages 276-284
    In this research study, we prepared different thin films of ZnO:Cu, ZnO:Mo, and Zno:Mo:Cu using a magnetron co-sputtering method. At the best of our knowledge, it is the first time that one prepared co-sputtered Zno:Mo:Cu thin films. We also annealed the samples at 100, 200, 400, and 800 °C. The samples were both theoretically and experimentally. We investigate the AFM results of the samples in the above-mentioned temperatures and compare different parameters of saturation roughness, height density function, and permutation entropy. The results demonstrated that the height density function became wider and the roughness decreased at higher temperatures. Moreover, the plot of permutation entropy versus roughness enabled us to distinguish between our samples.
    Keywords: Roughness, Permutation entropy, Atomic Force Microscopy (AFM), Composite thin film, Temperature
  • Marziyeh Rohaniyan, Abolghasem Davoodnia *, S. Ali Beyramabadi Pages 285-296
    In this study, a new application of a keplerate-type giant-ball nanoporous isopolyoxomolybdate, (NH4)42[MoVI72MoV60O372(CH3COO)30(H2O)72], denoted as ({Mo132}), in the synthesis of tetrahydrobenzo[a]xanthene-11-ones via a one-pot, three-component reaction of β-naphthol, aryl aldehydes, and dimedone is reported. The reactions were performed under the solvent-free conditions, providing the corresponding products with high atom economy ranging from 90.77% to 92.32%. The catalyst was prepared using inexpensive and readily available materials and could be easily recovered from the reaction mixture by a simple filtration and reused many times with no significant loss of its catalytic activity. High activity of the catalyst, excellent yields, short reaction time, simple procedure with an easy work-up, and the absence of any volatile and hazardous organic solvents are other advantages of the present methodology.
    Keywords: Giant-ball nanoporous isopolyoxomolybdate, Keplerate, {Mo132}, tetrahydrobenzo[a]xanthene-11-ones
  • Mehdi Nabati *, Hamideh Sabahnoo, Vida Bodaghi Namileh Pages 297-310

    This work evaluates the stability of tecnethium-99m methylene diphosphonate (99mTc-MDP) radiopharmaceutical and identifying its precise molecular structures and analyzing their binding to osteocalcin receptor. At first, different formulations of 99mTc-MDP cold kit were made in various conditions. Then, various molecular structures were evaluated and optimized using B3LYP/Lanl2DZ level of theory by Gaussian software at room temperature. The stability and reactivity properties of the optimized molecular structures were calculated using Frontier molecular orbitals (FMOs) theory. The binding of the molecular structures with the said receptor was analyzed using the molecular docking study. The investigation results indicated that the interactions between the molecular structures and osteocalcon receptor were related to the residues Leu 25, Asn 26, Asp 30, Cys 29, Tyr 42, Tyr 46 and Phe 38

    Keywords: Medronate, methylene diphosphonate, Molecular docking, Molecular Simulation, Nuclear medicine, Osteocalcin receptor
  • Elahe Faramarzi, Reza Ghiasi *, Masumeh Abdoli Senejani Pages 311-323

    In this study, the stabilities of trans-2,3- and trans-2,5-dihalo-1,4-dioxanes conformers were investigated at the LC-BLYP/6-311+G(d,p) theory level. The total energies and dipole moments of the axial and equatorial conformations were calculated for the mentioned molecules. The stability of theconformers, bond distances and spin-spin coupling constants of C-Hax and C-Heq bonds were explained with the negative hyperconjugative anomeric effects. The negative hyperconjugative anomeric effects on these conformers were illustrated using the natural bond orbital (NBO) analysis. Deformation maps of electron density for these conformers were provided, as well. In the basis of these calculations, the axial conformer was more stable than equatorial conformer in the studied molecules. Moreover, the trans-2,3- and trans-2,5-dihalo-1,4-dioxanes molecules were iso-energetic.

    Keywords: 4-Dioxane, negative hyperconjugative effect, conformers, natural bond orbital analysis, electron deformation density
  • Elham Haddazadeh, Mohammad Kazem Mohammadi * Pages 324-332
    Tri substituted imidazole derivatives were synthesized with the combinations of phenanthroquinone, benzealdehyde derivatives at the presence of ammonium acetate that catalyzed by Lewis acid. In all reactions, polar solvent was used and the reactions were carried out under the reflux conditions. The structure of all compounds was confirmed using the IR and 1HNMR. This method revealed several advantages including, excellent yields, simplicity of operation and easy separation. The results showed that, products formed in high yields and low reaction times. Also, the metal atom of Lewis acid catalyst increased the reactivity of substrate and the reaction time.
    Keywords: Multicomponent, One-pot, Imidazoles, ammonium acetat, Lewis acid
  • Aliakbar Dehno Khalaji * Pages 333-339

    In this work, the Schiff-base compound N,N΄-bis(2,4-dimethoxybenzylidene)-butane-1,4-diamine monohydrate ((2,4-MeO-ba)2bn/H2O) was prepared by the condensation reaction of 2,4-dimethoxybenazaldehyde with butane-1,4-diamine in methanol solution and crystallizes as the monohydrate. The crystal structure of (2,4-MeO-ba)2bn/H2O (1) was determined using the X-ray diffraction (XRD) analysis. The compound crystallized in the monoclinic space group C2/c, with a=14.7116 (10), b=15.7333 (9), c=10.2013 (6) Å, β=112.704 (2)° and Z=4. There are one half-molecule and one half of a water molecule in the asymmetric unit, with the (2,4-MeO-ba)2bn molecule completed by inversion symmetry on the midpoint of the central C-C bond of the butane unit and the O atom of the water molecule situated on a twofold rotation axis.  Within the imine functionality, the N-C bond lengths of 1.2643 (19) and 1.457 (2) Å were double and single bonds, respectively. Hydrogen bonds of the type O-H∙∙∙N between the water molecule and the imine nitrogen atom of the (2,4-MeO-ba)2bn molecules led to formation of the layers propagating parallel to (100). The 1H-NMR and FT-IR results confirmed the preparation of this ligand, as well.

    Keywords: Schiff-base, Condensation reaction, crystal structure, Hydrogen bonding
  • Preeti N. Yadav, Usmangani K. Chhalotiya *, Kesha M. Patel, Jinal N. Tandel Pages 340-358
    In this work, an accurate, sensitive, reproducible and precise stability indicating high performance liquid chromatographic (HPLC) method and ultra violet (UV)-visible spectroscopic method were established for the quantification and validation of β adrenergic drug mirabegron in bulk and its pharmaceutical dosage form. High performance liquid chromatography is a physical separation technique for a mixture of compounds that are dissolved in solution. Mirabegron is in a class of medications called diuretic. The HPLC method was developed with proposed chromatographic condition with mobile phase containing acetonitrile: water (50:50, v/v) adjusted pH 9 with 1 mL of 1% TEA. Accomplishment of UV-visible spectroscopic determination was done at wavelength maxima of 247 nm using methanol as a solvent. The linearities were in the range of 2-18 µg/mL for UV-visible spectroscopic method and 0.01-20 µg/mL for HPLC method, respectively. Validation of proposed method has been accomplished with respect to linearity, accuracy, precision, specificity and robustness. Forced degradation study has been performed under different conditions like acid and alkali hydrolysis, chemical oxidation, dry heat degradation and photolytic degradation study by use of stock solution of mirabegron and quantification has been achieved by proposed reverse phase-liquid chromatography (RP-LC) method. Mirabegron is susceptible to acid and base hydrolysis, chemical oxidation, dry heat and photolytic degradation studies; found that degradants are well resolve from parent drug peak of mirabegron. Due to the sensitivity, promptness and accuracy of methods, we rely on that the both intended methods will be useful for the regular quality control analysis and quantification of drug in bulk and pharmaceutical dosage form.
    Keywords: Validation_Mirabegron_Forced degradation study_HPLC_UV – Visible Spectroscopy_Adrenergic
  • Sahar Parchizadeh *, Mohammad Fazilati, Hossein Salavati, Behrooz Salehi Eskandari, Habibollah Nazem Pages 359-368

    Propionibacterium is a gram-positive genus, anaerobic to microaerophilic, and rod-shaped from propionic bacteriaceae family that is capable of producing propionic acid using transcarboxylase enzymes. The aim of this study was to investigate the effect of physicochemical parameters (temperature and pH) and ascorbate peroxidase and catalase levels at different concentrations of folic acid in Propionibacterium freudenreichiii to produce better and more vitamin B12. The Propionibacterium freudenreichii was inoculated into fermented medium containing soaked corn. Folic acid was added to the fermentation medium at different concentrations, then its absorption at 600 nm, at different temperatures and pH, was investigated. The results revealed that, the optimum pH for bacterial growth was 6.6 and the optimum bacterial growth was at 25-40 °C. Addition of folic acid at lower concentrations to the culture medium of Propionibacterium freudenreichii increased the UV absorption at 600 nm. It was found that, high concentration of folic acid reduced the growth rate which, indicating the negative effect of the folic acid on bacterial growth. Catalase and ascorbate peroxidase activity was determined based on H2O2 consumption at 240 nm and 290 nm. In this bacterium, CAT and ascorbate peroxides activity decreased significantly with increasing folic acid concentration. It was also found that folic acid functioned as a toxin for this bacterium at high concentrations and demonstrated antioxidant properties.

    Keywords: Propionibacterium freudenreichii, Folic acid, Catalase, Ascorbate peroxidase