فهرست مطالب

Physical Chemistry Research - Volume:8 Issue: 2, Spring 2020

Physical Chemistry Research
Volume:8 Issue: 2, Spring 2020

  • تاریخ انتشار: 1399/01/23
  • تعداد عناوین: 12
|
  • Nastaran Parsafard *, MohammadHassan Peyrovi, Mahdi Abdali Hajiabadi Pages 203-213

    A co-impregnation method was applied to the Ni/Zr-HMS/HZSM-5 catalyst (with various amounts of zirconium) during the hydrogenation of benzene. The physicochemical properties of the prepared nickel catalyst were characterized using X - ray diffraction, X - ray fluorescence, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, temperature-programmed desorption of ammonia, H2 chemisorption, N2 adsorption - desorption, and thermogravimetric analysis. The catalytic performance was assessed on a fixed-bed reactor (reaction temperature between 130 °C and 190 °C). The results indicated that the nickel catalyst with Si/Zr = 35 exhibited better catalytic performance and stability than others, so providing a better selectivity in long-term performance.

    Keywords: Impregnation, Hydrogenation, Conversion, Selectivity, Stability
  • Wan Zhong Yu * Pages 215-223

    Based on topological chemistry theory, a quantum chemistry method is used to calculate the 91 electrical distance vector (Mi) of a molecule, which is used to characterize the chemical microenvironment in which the molecule is located. The multivariate stepwise regression method was used to screen the variables to obtain the ternary best equation. Correlation coefficient R2=0.887, R2CV=0.673, passed by FIT and AIC .The ternary variable is used as the input set, and the inhibition rate is used as the output set. The LS-SVM and Elman-ANN algorithms are used for prediction and comparison. The results show that R2 is 0.993 and 0.994 respectively. The prediction ability is similar. But the stability of Elman is better, and the two-dimensional structure affecting the molecule is structural fragments such as =CH-, -CH<.

    Keywords: LS-SVM, Elman-ANN, QSAR, Molecular electronegativity distance vector
  • SeyyedMojtaba Mousavi, Aziz Babapoor, SeyyedAlireza Hashemi, Bijan Medi * Pages 225-240

    Nitrobenzene (NB) has a wide range of usages as a chemical intermediate and also as a dye in printing applications. Despite its advantages, NB is harmful to human and animals and hence is an environmental pollutant. In this research, NB removal from water was studied via adsorption on graphene oxide (GO) coated by polythiophene (PT) nanoparticles. The resulting nanocomposite was characterized by XRD, FTIR, BET, and SEM. While the FTIR tests proved successful incorporation of PT, the SEM images displayed a relatively larger surface area compared to other studies. The BET analysis confirms this finding by reporting the surface area as 917.8 m2/g for the adsorbent. The adsorption mechanism was assessed by the Langmuir and Freundlich isotherms. The results show that the Freundlich isotherm better describes the adsorption process compared to the Langmuir isotherm. On the other hand, the pseudo-second-order kinetic model better regresses the experimental results, which indicates a chemical adsorption mechanism. The adsorption-desorption behavior of the samples was evaluated at optimized pH, time, adsorbent dosage, and eluent type. The results showed that the synthesized nanocomposite can efficiently remove NB from solutions in the pH range of 5.0 to 7.0, with the maximum adsorption capacity of 15.6 mg/g.

    Keywords: Nitrobenzene, graphene oxide, Polythiophene, Adsorption
  • Khorshid Darvishi Ganji, Fateme Mirzajani *, Atousa Aliahmadi, Alireza Fakhari Zavareh, Alireza Ghassempour Pages 241-250

    Herein, the protein corona formation on the spherical metal nanoparticles was studied to investigate the possible effects of silver nanoparticles (AgNPs) on the protein activity and conformation. The digestion capability of trypsin was monitored on the human serum albumin (HSA) at standard enzymatic hydrolysis conditions in the absence and presence of different concentrations of AgNPs. So the ratio of enzyme:HSA, the duration and the temperature of nanoparticle treatment were evaluated. The activity of treated trypsin molecules, in the form of hard (HC) and soft corona (SC) were studied using sodium dodecyl sulfate poly acrylamide gel electrophoresis (SDS-PAGE), and nano liquid chromatography electrospray (ion trap) mass spectrometry (nano LC-ESI/MS, LC-ESI/MS). In addition the characteristics of silver nanoparticles and the formation of HSA corona on the nanoparticle surface were monitored using ultra-violet/visible spectroscopy (UV-Vis), Dynamic light scattering (DLS) and fluorescence spectrophotometry. The results demonstrated that not only the corona formation but also the AgNPs/Trypsin interaction, decreases the hydrolysis potency of trypsin. Furthermore, the encountering of the AgNPs/HSA could influence both nanoparticles and HSA molecule features. Accompanied with fluorescence study, that the HSA secondary structure. Also LC-ESI/MS data revealed the most affected HSA triptics have α-helix structure.

    Keywords: Human Serum Albumin, Protein corona, Silver nanoparticles, Trypsin, Enzymatic potency
  • Najmeh Tazang, Farzad Alavi *, Jafar Javanmardi Pages 251-266
    An accurate prediction of the absorption and desorption of Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) is important for the estimation of BTEX emissions from glycol units in natural gas processing plants. This work presents an approach to accurately model the solubilities of BTEX in triethylene glycol (TEG). The absorption of gases studied in this work into TEG is physical in nature, and therefore is treated as physisorption in modeling. The Huang-Radosz version of Statistical Associating Fluid Theory (SAFT-HR) Equation of State (EoS) was utilized to estimate the solubilities of BTEX in TEG. A new set of SAFT parameters for TEG, as well as a new set of binary interaction parameters between TEG and other components were obtained by fitting experimental vapor pressure and liquid density of TEG and available experimental binary VLE data, respectively. Using these parameters, solubility of multicomponent gases in TEG are accurately predicted. To have an estimate of the relative accuracy of SAFT-HR EoS, the results from Perturbed–Chain SAFT (PC–SAFT) and Peng–Robinson (PR) EoS are also reported. The overall average of root–mean–square deviation (RMSD) for binary and ternary systems studied in this work, using SAFT-HR, PC–SAFT, and PR EoS obtained equal to 0.12, 0.20, and 1.56, respectively.
    Keywords: Equation of state, Solubility, Absorption, Triethylene Glycol, BTEX, SAFT EoSmodel
  • Majid Mohadesi *, Raziye Rezaei Pages 267-280
    Acetic acid is one of the most important carboxylic acids which is used in many reactions, including the synthesis of acetic esters. Because of industrial and environmental advantages, the separation of acetic acid from dilute aqueous solutions has recently received much attention. In this study we investigated liquid-liquid equilibrium of a ternary system consisted of water+ acetic acid+ organic solvent at various temperatures. In this study, various thermodynamic models (Non-Random Two-Liquid (NRTL) and Universal Quasi-Chemical (UNIQUAC) models) were used to predict the composition of component in aqueous and organic phases. In these models, intermolecular interaction were considered as a binomial function of reverse temperature. The parameters of two models were determined through the optimization of an objective function. Root mean square deviations of the NRTL and UNIQUAC models to predict the composition of the components in the ternary mixture of water+ acetic acid+ organic solvent were 0.0273 and 0.0422, respectively.
    Keywords: Liquid-liquid equilibrium, Ternary system, organic solvent, NRTL model, UNIQUAC model
  • Abubakar Hamisu, Umar Gaya *, Abdul Abdullah Pages 281-295
    For the first time, a facile method is introduced to obtain ultrathin, mesoporous TiO2 nanosheets by the alkali precipitation of aqueous TiCl3 in the presence of NH4OH, and in-situ templating with polyvinyl alcohol (PVA). The synthesized titania have been characterized by N2 adsorption-desorption measurements, x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermo-gravimetric analysis (TGA) and ultraviolet-visible (UV-vis) spectroscopy. The obtained titania were hexagonal-like, detached, non-agglomerated, polydispersed, sub-20 nm nanodiscs. Unlike in doping methods, their surface area and pore volumes of can easily be tailored devoid of any wavelength shift, by simply tuning the amount of the template. Accordingly, their aggregation as microspheres can successfully be controlled by the templating step. The remarkable photoactivity of these nanoscopic materials has been confirmed by the degradation of aqueous methyl orange.
    Keywords: Anatase, Mesoporous, TiO2, Template, Photocatalysis, Precipitation
  • Misbaudeen Abdul Hammed *, Banjo Semire, Samuel Adewale Adegboyega, Abel Kolawole Oyebamiji, Temitayo Ayodele Olowolafe Pages 297-311

    Inhibition of cyclooxygenase-2 (COX-2) and thymidylate Synthase (TS) enzymes play prominent chemopreventive and chemotherapeutic roles in colorectal cancer studies. Basic computational investigation on the inhibition of these enzymes by sphingomyelin (SM) derivatives was carried out in silico using Density Functional Theory (DFT) and molecular docking studies. Interactions between SM with unsaturated fatty acids, COX-2 and TS were compared with that of 5-Fluorouracil (5-FU) and Celecoxib, the standard anti-colorectal cancer drugs. The results showed that SM with alpha-linoleic acid derivative possesses the highest HOMO (-4.70 eV) and lowest LUMO (0.09 eV) energies, which may enhance their interactions with their target receptors. All SM molecules, irrespective of the fatty acid nature have lower binding affinities, (ΔG = -5.5 to - 6.8 kcal/mol) against COX-2 than Celecoxib (-10.1 kcal/mol), indicating that the standard COX-2 inhibitor is much stronger than the natural SM. However, some of the natural SM are stronger inhibitors of thymidylate synthase than the standard drug, 5-FU, with SM having alpha-linoleic acid derivative (ΔG = - 6.2 kcal/mol) higher than 5-FU (ΔG = -5.28 kcal/mol), but lower than that of the active drug metabolite, 5-FdUMP (ΔG = - 7.4 kcal/mol). These ligand-protein interactions were all feasible and spontaneous.

    Keywords: Cyclooxygenase-2, thymidylate synthase, Sphingomyelin derivatives, DFT
  • Mohtaram Janighorban, Nasrin Sohrabi, Nahid Rasouli *, Mehrorang Ghaedi Pages 313-341
    Modified Zn2Al-layered double hydroxide (LDH) intercalated with Quinoline Yellow (Q) (Zn2Al-LDH/Q) was prepared by a facile and simple method and then used to remove of Cd2+ ions from water. The chemical composition and morphology of Zn2Al-LDH/Q was investigated by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Field emission Scanning electron microscopy (FE-SEM) and Energy-dispersive X-ray spectroscopy. Response surface methodology was employed to optimize the adsorption parameters of Cd2+ Such optimization was undertaken to ensure a high efficiency over the experimental ranges employed and to evaluate the interactive effects of the initial concentration of Cd2+, pH, adsorbent dosage, temperature and contact time in order to improve the conditions employed in the batch process. The analysis of variance (ANOVA) indicated that a second-order polynomial regression equation was the most appropriate polynomial for fitting the experimental data. The experimental confirmation tests showed a correlation between the predicted and experimental responses (R2). The optimum adsorption parameters were predicted as an initial Cd2+ concentration of 35 mg l-1, a pH value of 4.17, the adsorbent dosage of 0.03 g/L, a temperature of 32.5 °C and contact time of 51 min. Under optimum conditions, the highest adsorption efficiency and maximum adsorption capacity were 45% and 12.18 mg/g, respectively.
    Keywords: Layered double hydroxide, Cd2+Adsorption, Response Surface Methodology, Quinoline yellow
  • Batoul Makiabadi, Mohammad Zakarianezhad * Pages 343-354

    In present work, the aggregation behavior of ion-pairs in [MIM+]2[C(CN)3-]2 ionic liquid was investigated. The quantum chemical calculations were carried out to determine the structural parameters, interaction energies, hydrogen bonding, physical and topological properties of the clusters formed in the ionic liquid of [MIM+]2[C(CN)3-]2. The solvent effect on the stability of clusters was examined. The Gibbs free energy of solvation and the Gibbs free binding energy of clusters in various solvents were calculated. The results show that with decreasing the polarity of the solvent, the tendency to the formation of aggregate increases. Also, the solvation energies of the clusters increase with decreasing the solvent's dielectric constant. The NBO analysis was performed to evaluate the charge transfer in complexes. The AIM analysis was performed in order to characterize intermolecular interactions.

    Keywords: [MIM+]2[C(CN)3-]2 Ionic liquid, Solvent effect, Aggregation, Interaction energy
  • Milind Joshipura *, Nimish Shah, Sudir Dabke Pages 355-364
    Predicting physical properties is one of the major requirements in process engineering. Equations of state (EoS) are widely used for predicting physical properties. Among many EoS, cubic equations of state (cubic EoS) are being used because they are simple and applicable over a wide range of temperature and pressure. However, these cubic EoS fail to predict properties of a compound having polarity, association as well as hydrogen bonding. In the present study a new generalization for cohesion factor, to be used with Peng-Robinson (PR) EoS was proposed. In developing the model, compound-specific parameters for nearly 300 compounds were generated. These compound-specific parameters were correlated in terms of the reduced dipole moment and critical compressibility factor. Proposed models were compared with models available in the literature. Vapor pressure, heat of vaporization, saturated liquid density and second virial coefficient of the compounds were predicted. It was observed that the models with reduced dipole predicted various properties accurately for highly polar compounds without losing accuracy in predicting properties for non-polar compounds.
    Keywords: PR EoS, Cohesion factor, Reduced dipole, vapor pressure
  • Timmeswara Sarma Nori *, Ch Srinivasu, Sk Baba Vali, P Srinivasa Sastry Pages 365-372

    Viscosities and densities are measured experimentally for three binary liquid mixtures of Aniline + Toluene, Aniline + o-Xylene and Aniline + Mesitylene using Ostwald’s viscometer and Specific gravity bottle at T = 303.15 K. Viscosities have also been calculated using empirical relations viz., Bingham relation, Kendall-Munroe relation, Arrhenius -Eyring relation, Croenaurer-Rothfus-Kermore relation and Gambrill relation. The validity of these correlations has been verified by respective deviations between calculated values and experimental values. These results show that positive deviations are present in all the three binary mixtures at T = 303.15 K. The results of all the relations are comparatively in good agreement with experimental results. These are used to draw the characteristics of the molecular association among the components of respective binary liquid mixtures.

    Keywords: Gambrill relation, Bingham relation, Experimental viscosity, Organic liquid mixtures, Deviation