Iranian Journal of Chemistry and Chemical Engineering
Volume:34 Issue: 2, Mar-Apr 2015

The synthesis of 3-amino-1-nitroguanidine (3-ANQ) and 5-hydrazino tetrazole (5-HT) derivatives as new energetic materials are described. Reaction of 3-ANQ with triethyl orthoformate leads to the formation of 3-nitramino triazole while no reaction was observed whit 5-HT. Addition of NaN3 to a mixture of 3-ANQ and triethyl orthoformate, afforded 1-nitroguanidyl tetrazole in excellent yield. On the other hand, these compounds showed different reactivity toward dicyandiamide. Cyclization of 5-HT with dicyandiamide in EtOH/Water reflux caused formation of 3,5-Diamino-1-(1H-tetrazol-5-yl)-1H-1,2,4-triazole in good yield, nitration of which afforded 3,5-Dinitramino-1-(1H-tetrazol-5-yl)-1H-1,2,4-triazole as a potentially new high energetic molecule. No reaction was observed between 3-ANQ and dicyandiamide. The reaction of 3-ANQ and 5-HT were exanimated with trichloro triazine (TCT). 5-HT gave mixture of products while no reaction between 3-ANQ and TCT was detected. Unusual hydrazone condensation was observed between 3-ANQ and acetone, when acetone/water mixture used as solvent at 0 °C.

Grafting polymerization was a valuable method for the modification of the chemical and physical properties of polymer surfaces. In this paper, the grafting of cationic vinyl monomer with quaternary ammonium groups, methacryloxyethyltrimethyl ammonium chloride (DMC), onto the isotactic polypropylene (iPP) granule was performed by suspension solid-state grafting process. The technique offers new opportunities in modification of polyolefins, which had the advantages of solventless, lower process temperature. The grafted PP was systematically characterized by using various analytic tools including FT-IR, DSC and TGA. The FT-IR spectra of the grafted iPP confirmed that DMC was successfully grafted onto the iPP backbone. The influences of the reaction parameters such as the concentration of DMC, the dose of styrene, initiator concentration, swelling time, reaction time, reaction temperature were investigated. The optimum condition for the grafting of DMC onto the iPP granules was obtained within the range studied. Furthermore, the results of TGA and the hydrophilicity measurement indicated that the thermal stability of the grafted iPP was enhanced remarkably, and the hydrophilicity was also enhanced due to the addition of hydrophilic quaternary ammonium groups. This research is worthwhile and it can be foreseen with a great prospect in the developing of anti-static and antiseptic materials.

In the present study, Floating Drug Delivery Beads (FDDS) were prepared with sodium alginate/ starch blend as a matrix, sodium hydrogen carbonate as a pore forming agent, methyl cellulose as a binder and barium chloride solution as a hardening agent. In order to prepare the beads with different porosity and morphology the ratio between pore forming agent to polymer blend and ratio of the constituents of the blend were varied. Ciprofloxacin hydrochloride was used as a model drug for in-vitro studies. The swelling property of the dry beads is found to be in the range of 80% to 125% from its original dimension. The amount of drug released from the beads was measured by UV-Visible spectrometer at λmax of 278. The drug release from the floating beads can be varied from 7% to 67% by varying the ratios of composition of the blend and pore forming agents to the polymer blend. From the results it is proved that this system can be used as an oral delivery system with an ability of controlled release of drug in a sustained manner.

The complexation reaction between hydroxyl ammonium (HONH3+) cation with 18-crown-6 (18C6) ligand was studied in dimethylsulfoxide – water (DMSO-H2O), methanol – water (MeOH-H2O) and dimethylformamid – methanol (DMF-MeOH), binary solutions at different temperatures using conductometric method. The obtained results show that the stoichiometry of the complex formed between HONH3+ cation with (18C6) in all of the binary mixed solvents is 1:1[ML], as well as, these results show that the nature and the composition of the solvent systems are important factors that are effective on the stability of the complex formed between the macrocyclic ligand and metal cation in solutions. A non-linear behavior was observed for changes of stability constants of the complex versus the composition of the binary mixed solvents. The values of thermodynamic parameters show that the thermodynamics of complexation reaction is affected by the nature and composition of the mixed solvents and the complex is entropy stabilized, but enthalpy destabilized in most compositions of binary solutions.

A new sorbent composed of 3-aminopropyltriethoxy-silane-coated magnetic nanoparticles, functionalized with rhodium(III) porphyrin complex was synthesized and characterized by elemental analysis, X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR) and ThermoGravimetric Analysis (TGA). The effect of some co-existing anions present in aqueous solutions, pH, sorbent dosage and contact time on the thiocyanate removal was investigated. Thiocyanate adsorbing material was regenerated with 15 mM NaOH up to 97.0 %. The effectiveness and feasibility of the proposed sorbent for removal of thiocyanate ions from aqueous solutions is proved.

Graphene, a new member of the carbon family, was used as an adsorbent due to its exceptional capability to remove Rhodamine B (RB) and Malachite Green (MG), two organic dyes, from aqueous solutions. Adsorption kinetics of RB and MG onto graphene and adsorption capacity of the adsorbent were studied. Also the effects of parameters, including pH, contact time, temperature, and adsorbent dosage were studied. The adsorption process was followed using UV-visible spectroscopy. The isotherm analysis indicated that Freundlich and Langmuir isotherms are suitable for RB and MG, respectively. Pseudo-first- and pseudo-second-order models were considered to evaluate rate parameters. The kinetic experimental results fitted well the pseudo-second-order model for the two dyes, with correlation coefficients being greater than 0.99. Thermodynamic studies indicated that the adsorption processes is spontaneous for both the dyes, and exothermic for RB and endothermic for MG.

In the paper we developed a new method to determine the absolute amount of adsorption. This method relies on the excess adsorption isotherm and the density profile in the pore of one material. To compute the density profile and decrease complex calculation of obtaining the absolute amount of adsorption we introduced Simplified Local-Density (SLD) model. A few of appropriate parameters were acquired to calculate the density profile through SLD models the adsorption isotherm of methane on AX-21 activated carbon. In these parameters specific surface area and slit width is close to the true value of the AX-21 activated carbon. And we found SLD can accurately simulate the adsorption of supercritical methane on activated carbon and the precision rises up as temperature raises. The corresponding application of our method on adsorption of methane on AX-21 activated carbon was introduced at different temperature from 233 to 333K. The absolute isotherms of adsorption calculated by our method are reasonable when compared to other results.

The poly(ethyleneimine)-functionalized silica has been developed successfully as an effective adsorbent for the adsorption removal of Cu(II) ions from electroplating wastewater. The influences of pH, contact time and initial concentration of Cu(II) ions on the adsorption capacity and the effect of adsorbent dosage on the removal efficiency of Cu(II) ions from electroplating wastewater were investigated. The adsorption behaviors and mechanisms of Cu(II) ions onto poly(ethyleneimine)-functionalized silica were also studied in details. The uptake of Cu(II) ions on poly(ethyleneimine)-functionalized silica was constant in the range of pH 4-8. The poly(ethyleneimine)-functionalized silica offered a fast rate for the adsorption of Cu(II) ions and reached an equilibrium state within 30 min. The results of static batch experiment indicated that the maximum static adsorption capacity of Cu(II) ions on PEI-functionalized silica was 31.8 mg/g. The adsorption process was found to follow a pseudo-second-order rate mechanism. Langmuir adsorption isotherms fitted well in the experimental data. The optimum dosage of poly(ethyleneimine)-functionalized silica for the removal Cu(II) ions from electroplating wastewater was 10 g/L. The removal efficiency of Cu(II) ions from electroplating wastewater was 92.6%.Some scale-up experiments were also investigated to offer the reference for water treatment. The results showed that poly(ethyleneimine)-functionalized silica could be employed as an effective adsorbent for the removal of Cu(II) ions from electroplating wastewater.

Steel pipelines are susceptible to corrosion by the action of corrosive substance in the environment and one of the most common failure modes in buried pipeline coatingis cathodic disbondment. Consequently, Electrochemical Impedance Spectroscopy (EIS) was used to assess the effect of three important parameters, the thickness of coating, the artificial defect and electrolyte type, on cathodic disbondment, according to ASTM G8. Experiments were done in 3.5 % wt NaCl, KCl and CaCl2 solutions at room temperature with different coating thicknesses (354, 483 and 1014μm) and several artificial defects diameters (3, 6 and 9 mm). Immersion time was 28 days and during this period, a -1.5 V cathodic potential (vs. SCE) was applied. Further, the EIS measurements were done in Open Circuit Potential (OCP). Investigations showed that a thick polyurethane coating was highly resistant to cathodic disbondment in intact areas and that coating thickness increases caused decreases in the rate of cathodic disbondment in areas with defects. On the other hand, the evaluation on artificial defects showed disputable results, though with no logical correlations between artificial defects’ diameters and any disbonded area individually. In addition, assessment on electrolyte type showed the rate of cathodic disbonding might be classified after two parameters: solubility and mobility of ions. So, the disbonded area was dependent on the cation type in the electrolyte, and the anion diffusion had less effect in the cathodic disbondment process. Furthermore, the comparison between the cations and the anions in solution showed that the most important coating disbondments occurred when cations / anions are in a 1:1 ratio.

This study was devoted to the development of pulp Luffa Cclindrica and its characterization paper (annual plant fiber of the family Cucurbitaceae). Baking at soda helps to achieve a high level of delignification (Kappa ≤ 10) and high yield (≈ 67%).The beatability stack Valley is comparable to refined wood fibers, the fibers develop a normally time with good hydrophilic properties without excessive morphological variations. The Comparing to the same level of physical properties of refining pulp Luffa cylindrica with different pulps annual plants (straw, bagasse or kenaf), obtained by different processes, shows good mechanical properties of the fibers, in addition its behavior would tend to approach more the hardwood pulps. The measured thermal conductivity on the handsheets Luffa Cylindrica was found equal to 0.112 W / m K, value being also in the rather broad range of the data of the literature on different types of pulp, between 0.1 and 0.2 W / m K.

To enhance solubility and the performance of a plant gum (from south peach tree of China, SP gum) as a drilling fluid additive, we explored the potential of Modified SP (MSP) gum by modifying it with epichlorohydrin. The modification conditions, such as the mass ratio of the crosslinking agent, pH and temperature, were optimized and the results show that 56.40 g/100g mass ratio of the crosslinking agent to SP gum with pH=10 at the temperature of 50°C lead to the Modified SP (MSP) gum showed the well performance in the water based drilling fluids.It was discovered that drilling fluids modified with 0.5%wt MSP demonstrated more excellent rheology and lower filtration than that of SP treated drilling fluids, which should be contributed to the good clay inhibition obtained from swelling experiment and high inhibitive to the hydration and swell of the mud supported by mud ball immersing experiments.

Determining the optimal location of wells with the aid of an automated search algorithm is a significant and difficult step in the reservoir development process. It is a computationally intensive task due to the large number of simulation runs required. Therefore,the key issue to such automatic optimization is development of algorithms that can find acceptable solutions with a minimum number of function evaluations. In this study, the Differential Evolution (DE) algorithm is applied for the determination of optimal well locations. DE is a stochastic optimization algorithm that uses a population of solutions which evolve through generations to reach the global optimum. To investigate the performance of this algorithm, three example cases are considered which vary in dimension and complexity of the reservoir model. For each case, both DE algorithm and the widely used Genetic Algorithm (GA) are applied to maximize a Modified Net Present Value (MNPV) as the objective function. It is shown that DE outperforms GA in all cases considered, though the relative advantage of the DE vary from case to case. These results are very promising and demonstrate the applicability of DE for this challenging problem.