Scientia Iranica
Volume:23 Issue: 6, 2016

ZrP2O7 and CuFe2O4 nanoparticles as ecient and reusable heterogeneous catalysts have been used for the preparation of 2H-indazolo[2,1-b]phthalazine-triones and 1H-pyrazolo[1,2-b]phthalazine-diones, respectively, under solvent-free conditions in good to excellent yields and short reaction times.

An efficient and mild condensation reaction of 6-aminouracil derivatives with various aromatic aldehydes and ethyl or methyl acetoacetate was performed in the presence of catalytic amounts of H14[NaP5W30O110]/SiO2 as a recyclable, eco-friendly and green nano-catalyst to afford the desired pyrido[2,3-d]pyrimidine derivatives in good to excellent yields.

Environmentally-friendly and highly efficient method has been developed by a sequential one-pot, three-component reaction between isocyanides, aldehydes and 2-aminopyridines or 2 aminopyrazines under solvent-free and grinding- conditions at room temperature in the presence of nano-ordered MCM-41-SO3H.

Oscillating chemical reactions are complex systems involving a large number of chemicalspecies such as ionic, radical and molecular intermediates, which exhibit fluctuation in their concentration with time. One of the oscillating chemical reactions is BZ {H2SO4-KBrO3-CH2(COOH)2-Ce(IV)}System. In this work for the first time a new, simple and appropriate method, i.e.conductometry, have applied for the investigation of BZ oscillating system.Furthermore, presence of SiO2 nanoparticles containing NiO apparently affected the intensity and period of BZ system. The effect of varying concentrationof , , and on the conductance of BZ oscillating chemical system at 20 (±0.1)°C was also investigated. The obtained results of this work indicated that rather than potential and color of the BZ system, the conductance of system is also oscillates during the reaction and is also proportional to the reactants concentration as well. The intensity, intensity and period of the oscillation are strongly depending on the concentration of reactants.

N-Aarylation of imidazole, benzimidazole, pyrazole, and indole was performed in the presence of CuI as the catalyst and NaOH as the base in ethylene glycol medium. Apparently, ethylene glycol played a dual role as both the reaction solvent and a ligand for the catalyst. All reactions proceeded selectively to give the corresponding N-arylated products. In some cases, O-alkylation or dehalogenation was observed which was explained by the proposed catalytic cycle. Conventional heating at 120 oC and microwave irradiation both were used, where the results showed that microwave irradiation could facilitate the reaction by lowering the reaction times and increasing the yields. The reaction medium was recovered and reused in several consecutive runs.

The simple method of fabrication of crystalline superparamagnetic nanoferrite (Fe3O4) particles using oxidative hydrolysis of Fe (II) salt in deep eutectic solvent-water mixture is being reported. The spectral properties of Fe3O4 nanoparticles were characterized by Fourier Transform Infrared (FTIR) spectroscopy while X-Ray diffraction (XRD) as well as scanningelectron microscopy (SEM) techniques were used to estimate the crystalline structure and particle size. The results of the studies revealed that this technique could be adopted to synthesize agglomerate-free superparamagnetic Fe3O4 nanoparticles in the simple manner in deep eutectic solvent which may find potential application in the biosensor and corrosion protective coatings.

An array of 1, 4-dihydropyridines (DHP) derivativeswas synthesized by Hantzsch three-component reaction of aromatic aldehydes, ethyl acetoacetate and ammonium acetate using trichloroisocyanuric acid (TCCA) as an efficient catalyst in aqueous media. The proposed method was operationally simple and to make the process benign for the environment, water used as a reaction medium. No aromatization of dihydropyridinesproducts was done in the presence of TCCA as an oxidant.

In seismic numericalmodelling, it is readilyto simulate the wave field of the cavities with simpleandregular geometric boundaries. However, the real cavities are always complex or irregular, such asgeneral quadrilateral orhorny model. In this paper, conformal mapping is applied to three representative cavity models, including a pentagon model, a generalized quadrangular model and a horny model. First of all, transform the original cavity modelinthephysical domain into certain simple regularmodelin the computational domain and accordingly transform the boundary condition inthephysical domain into that in the computational domain. Thencalculate the wave field on the boundary in the computational domain. Finally, we generate the wave field on the boundary in the physical domain by usingthe inverse conformal mapping,when the conformal mappingfunctionis invertible. Twoexperiments by adoptingeither a displacement boundarycondition or a stress boundary conditionillustratethat the wave fields for three different kinds of cavitiesmainly concentrate on the boundary of the corresponding cavity.

This work is devoted to the study of heat transfer effects in peristaltically induced flow of an electrically conducting viscous fluid in an asymmetric channel. An incompressible fluid fills the porous space in a channel. Analysis is made in the presence of Hall and ion-slip effects. The effects of velocity and thermal slips at the boundaries are considered. The problems which govern the fluid flow and heat transfer are modeled in the wave frame of reference. Exact solutions have been constructed under realistic assumptions. Important features of peristaltic motion and heat transfer are studied with the varying values of Hall parameter, ion-slip parameter, Hartman number, permeability parameter, velocity slip parameter and thermal slip parameter. The graphical results for the field quantities are given in detail.

A series of bitumen/nano clay nanocomposite have been prepared through solvent intercalation technique by using mechanical agitation and sonication process. The structure of nanocomposite coatings was investigated by TEM, low angle X-ray diffraction and Fourier-transform infrared spectroscopy. To investigate barrier properties of nanocomposite coatings, polarization, salt fog test and pull-off adhesion tests have been employed. The results showed that bitumen/MMT nanocomposite coatings were superior to the pristine bitumen coating in corrosion protection effects. Also, it was observed that the corrosion protection of bitumen/clay nanocomposite coatings improved as the clay loading is increased up to 4 wt.%.

Petroleum refinery wastewaters (PRW) contain water-soluble hydrocarbons which can not be separated by physical methods. In recent years, there have been enormous approaches to treat PRW. The most outstanding methods involve biological, photocatalytic, electro photo-Fenton and etc. Using microbial fuel cell is a new method to treat PRW. In the present paper, treatment of petroleum wastewater of Isfahan refinery (COD= 213.9 mg/l, PH=7.1) was investigated in twochamber microbial fuel cell having 350 mL anode and cathode capacity. Anaerobic activated sludge prepared from Isfahan refinery treatment reactors was used as inoculum. Maximum power production was 0.03 W/m2 at 33 using oxygen as cathodic electron acceptor. Also COD removal efficiency was 49.27% during 44 hr. To enhance power production of the MFC, potassium permanganate was used as cathodic electron acceptor. At temperature of 33 and 0.2 g/l permanganate concentration, the maximum power density was 0.95 W/m2 and COD removal efficiency was 78% during 44hr. Then effect of temperature and external resistance on treatment of PRW was investigated. In fact the motivation of this paper is investigation of COD removal from PRW in two-chamber MFC.

The hydration and strength properties of the binder material created on α-C2SH basis were determined. The binder material was prepared by mixing α-C2SH (C/S = 1.5; 16 h, 200 oC) and quartz sand (1:1 by mass) in a homogeniser for 30 min. Later on, sample was ground in a vibrating cup mill at 950 rpm for 4 min and burned at 450 oC for 30 min under air atmosphere. It was determined that calorimetric curve of created binder material differs from the one of ordinary cements as it involves only the three exothermic reactions and the amount of total cumulative heat grows with the increasing hydration time. As expected, the tendency of strength increment was observed after 7-28 days of hardening: compressive strength increased to 15.5 and 24.0 MPa, respectively. The products of synthesis and hardening were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and simultaneous thermal analysis (STA).

The first step to study oil reservoirs is determination of reservoir fluid composition in both horizontal and vertical directions. In this research, fluid composition distribution is investigated as a result of diffusion and natural convection in a naturally fractured model. A two-component single phase fluid and a rectangular two-dimensional fractured oil reservoir with a known temperature profile are used in this study. MATLAB software is exploited to solve governing equations, numerically. According to results, thermal diffusion has the greatest impact on the variation of fluid composition, followed by pressure and molecular diffusions, respectively. Moreover, it is found out that even a small convection would change the fluid composition distribution, considerably. Fluids tend to flow through the fracture due to its high permeability; therefore, a counterclockwise convective cell would flow in the reservoir.

Olive mill wastewater (OMW) is a high organic load waste produced from the three-phase decanter system used in the processing of olives for oil that has phytotoxic and antibacterial phenolic compounds, which makes this waste to resist biological degradation. Foam fractionation has not yet been studied with regard to its potential for treatment of such wastewaters. In the present study, this technique was investigated in a simple model system. The effect of different operational conditions, namely, surfactant concentration, process time, pH and gas flow rate were evaluated in this study. Statistical analysis of the fractional factorial design revealed that the surfactant concentration, pH and the gas flow rate are the most influential process parameters. Low surfactant concentration and pH of 3-4 were found to be advantageous in terms of good chemical oxygen demand (COD) removal. More than 80% of COD was removed through a single stage foam fractionation process. This method has proved to be a feasible technique for the OMW effluent treatment.