Journal of Applied Chemistry The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Benign Methodology and Efficient Catalysis for the One-Pot Multicomponent Synthesis of Dihydropyrimidinones and Thiones: A New Key for Old Lock Wed, 09 Apr 2014 12:17:53 +0000 In the present communication, under the influence of microwaves, cuprous chloride has been demonstrated to be safe, mild, efficient, and inexpensive catalyst for the Biginelli discovered multicomponent reaction (MCR) between aromatic aldehydes, urea/substituted urea, and ethyl acetoacetate to produce structurally diverse dihydropyrimidin-2(1H)-ones (DHPMs) and thiones in an ecofriendly solvent-free protocol. The practical and simple protocol led to excellent yields of the dihydropyrimidin-2(1H)-one derivatives under mild reaction conditions and within short span of reaction times with easy reaction workup by maintaining excellent atom economy. Parvez Ali, Naziyanaz Pathan, and Taibi Ben Hadda Copyright © 2014 Parvez Ali et al. All rights reserved. Synthesis of Triphenyltin (IV) and Dibutyltin (IV) Complexes of 1-Aryl-2,5-dithiohydrazodicarbonamides and Their Characterization Wed, 05 Mar 2014 15:55:38 +0000 Organotin complexes of the types Ph3SnL and Bu2SnL [where Ph = phenyl and Bu = butyl; HL = 1-phenyl-2,5-dithiohydrazodicarbonamide (HPhthc), 1-benzyl-2,5-dithiohydrazodicarbonamide (Hbzthc), 1-(4-ethoxyphenyl)-2,5-dithiohydrazodicarbonamide (HEtOPhthc)] have been prepared. Molar conductance studies demonstrate the nonionic behavior of the complexes. The 1H and 13C nuclear magnetic resonance and FAB mass spectra of the complexes are consistent with the proposed stoichiometry. Infrared spectra suggest an anionic bidentate coordinating behavior of the ligands. Rashmi B. Rastogi, Karuna Singh, and Vinay Jaiswal Copyright © 2014 Rashmi B. Rastogi et al. All rights reserved. Chalcogenide Thin Film Substrate for Protein Biochip Application Wed, 05 Mar 2014 11:40:23 +0000 Diagnostic of pathogen in the human biological liquids by biochip technology is an intensively developed methodic now. The main and the most important part of biochip is the adsorbing layer. Adsorption properties of chalcogenide films to protein (rat monoclonal antibodies) were tested. The films were prepared by conventional thermal deposition technique and by pulsed laser deposition technique. Two methods were used for forming in the films the two-dimensional map of adsorbing places for probe testing. One is using photoresist properties of chalcogenide films; another is using photo-induced oxidation of chalcogenide films. It was shown Good selectivity of the developed structures to protein markers was shown. A. S. Tveryanovich, A. S. Vasileva, A. V. Belykh, E. N. Borisov, and Yu. S. Tveryanovich Copyright © 2014 A. S. Tveryanovich et al. All rights reserved. Measurement and Correlation for Solubility of Some Pyrimidine Derivatives in Different Solvents Mon, 03 Mar 2014 12:17:20 +0000 Some new pyrimidine derivatives have been synthesized and their characterization was done by IR, NMR, and mass spectral data. The solubility of these synthesized compounds has been studied in methanol, N,N dimethylformamide (DMF), and carbon tetrachloride (CCl4) by gravimetrical method from 298.15 to 328.15 K under atmospheric pressure and the solubility data were correlated against temperature. The solubility is found to increase with temperature and order of solubility is DMF > methanol > CCl4. The experimental solubility data is correlated with the modified Apelblat equation. Some thermodynamic parameters such as dissolution enthalpy, Gibbs energy of dissolution, and entropy of mixing have also been calculated. Kapil Bhesaniya and Shipra Baluja Copyright © 2014 Kapil Bhesaniya and Shipra Baluja. All rights reserved. Polyaniline/Palm Oil Blend for Anticorrosion of Mild Steel in Saline Environment Mon, 17 Feb 2014 13:54:19 +0000 The corrosion protective performance of polyaniline/palm oil (PAni-PO) blend coated on mild steel in 3% NaCl aqueous solutions has been evaluated by electrochemical methods, namely, open circuit potential (ocp), potentiodynamic polarization, and EIS spectroscopy. The surface of mild steel was covered by a dark green protective layer due to the physical interaction between the coating and steel. The permanent shifts of ocp and potentiodynamic polarization towards higher positive value of oxidation potential by about 800 mV and by a decrease in corrosion current density by sixfold in magnitude and an increase of 10 orders of magnitude in charge transfer resistance are due to protective coating. Mohd Rashid, Suhail Sabir, Afidah A. Rahim, and Umesh Waware Copyright © 2014 Mohd Rashid et al. All rights reserved. Synthesis and Spectral Characterization of Novel Spiroindan-1,3-Dione: A Diels Alder Adduct Mon, 30 Dec 2013 08:09:14 +0000 DMSO/Ac2O reagent converts 1,3-indandione (1) to an unusual dimer 1H,1′H-2,2′-biindene-1,1′,3,3′(2H,2′H) tetrone and a dimeric condensation product along with an ylide (1a) at room temperature. This reagent also brings about oxidation of secondary alcohols to corresponding ketones, methyl thiomethylation, and N-hydroxymethylation in phthalimide and converts 4-hydroxycoumarins and dicoumarol to different oxidative and degradation products under varying conditions. However, when 1,3-indandione was refluxed with DMSO/Ac2O reagent at 150°C, it afforded a novel compound, 2-spiroindan 1,3-dione (2), a Diels Alder Adduct, analogous to (3) obtained upon treatment of 1,3-indandione with formaldehyde in presence of primary amines. N. D. Zargar and K. Z. Khan Copyright © 2013 N. D. Zargar and K. Z. Khan. All rights reserved. Contribution of Ion-Exchange and Non-Ion-Exchange Reactions to Sorption of Ammonium Ions by Natural and Activated Aluminosilicate Sorbent Wed, 25 Dec 2013 16:11:50 +0000 The effect of acid and alkaline activation of complex natural aluminosilicate sorbent on its chemical composition, surface properties, and adsorption capacity towards ammonium ions was studied. An increase in specific surface area of the sorbent by 1.3 times after acid treatment and by 1.5 times after alkaline activation was shown. The change of ion-exchange complex of sorbent as a result of activation was observed. Sorption isotherms of ammonium ions on natural and activated samples were obtained and were satisfactorily described by the Langmuir equation. The evaluation and comparison of desorbed cations of alkali and alkaline earth metals were carried out. It was confirmed that ion-exchange processes primarily contributed to sorption of ammonium ions by natural and acid-activated silica-alumina, in contrast to alkali-activated one, for which absorption of nonexchangeable ammonium ions increased adsorption capacity of ammonium ions by 1.5 times. Larisa Belchinskaya, Lyudmila Novikova, Vladimir Khokhlov, and Jen Ly Tkhi Copyright © 2013 Larisa Belchinskaya et al. All rights reserved. Structural Transitions in Sheared Electrically Stabilized Colloidal Crystals Tue, 24 Dec 2013 17:49:18 +0000 A Landau theory is presented for the structural transition of electrically stabilized colloidal crystals under shear. The model suggests that a structural transition from an ordered layered colloidal crystal into a disordered structure occurs at a critical shear stress. The shear induced structural transition is related to a change of the rheological properties caused by the variation of the microstructure which can be verified by scattering experiments. The theory is used to establish the shape of the flow curves. A good qualitative agreement with experimental results can be achieved, while a scaling relation similar to the elastic scaling is established. Joachim Kaldasch, Bernhard Senge, and Jozua Laven Copyright © 2013 Joachim Kaldasch et al. All rights reserved. Analgesic, Anti-Inflammatory, and Antiplatelet Profile of Hydrazones Containing Synthetic Molecules Tue, 17 Dec 2013 10:24:31 +0000 Hydrazones are present in many of the bioactive compounds with wide interest because of their diverse pharmacological applications. Hydrazones possess wide variety of biological activities such as anticonvulsant, antidepressant, analgesic, anti-inflammatory, antiplatelet, antimicrobial, anticancer, antihypertensive, anthelmintic, antidiabetic, antiparasitic, and other anticipated activities. This created an interest for researchers towards synthesized variety of hydrazone derivatives for different biological activities. Therefore many researchers have synthesized hydrazone derivatives as target structures for their biological activities. This is paper focuses on the analgesic, anti-inflammatory, and antiplatelet activities of hydrazones. Mohammad Asif and Asif Husain Copyright © 2013 Mohammad Asif and Asif Husain. All rights reserved. Green Extraction: Enhanced Extraction Yield of Asiatic Acid from Centella asiatica (L.) Nanopowders Sat, 14 Dec 2013 10:58:07 +0000 Nanopowders of Centella asiatica (L.) were produced using planetary ball mill in order to investigate the differences of water extraction yield of asiatic acid as compared to micropowders of Centella asiatica. Effect of extraction time (20–60 min) on extraction yield of asiatic acid from Centella asiatica was examined. Results showed that water extraction of asiatic acid using Centella asiatica nanopowders exhibits was almost 50% higher extraction yield with 7.09 mg/g as compared to the micropowders of Centella asiatica. It was concluded that nanopowders contributed in enhancing water extraction yield of asiatic acid as compared to micropowders. Thereby utilizing nanopowders in water extraction could improve the extraction of asiatic acid via clean, eco-friendly, and less expensive process. M. Z. Borhan, R. Ahmad, M. Rusop, and S. Abdullah Copyright © 2013 M. Z. Borhan et al. All rights reserved. Development of Stability Indicating LC Method for the Estimation of Tolperisone in Bulk and Pharmaceutical Dosage Form Tue, 10 Dec 2013 11:26:57 +0000 A rapid, specific, and sensitive reverse phase high performance liquid chromatographic method has been developed and validated for analysis of tolperisone in both bulk and pharmaceutical dosage form. The HPLC method was performed with a reversed phase C18 SunFire column (250 mm × 4.6 mm i.d., 5 mm particle size), detection at 261 nm and a mixture of methanol, water and pH 7.5 adjusted by use of 1% solution of triethylamine (60 : 40) as mobile phase. The flow rate was 1.0 mL min−1 and effluents were monitored at 261 nm. The retention time of tolperisone was 4.8 min. Tolperisone was subjected to acid and alkali hydrolysis, chemical oxidation, wet hydrolysis, dry heat degradation, and sunlight degradation. The degraded product peaks were well resolved from the pure drug peak with significant difference in their retention time values. Stressed samples were assayed using developed LC method. The proposed method was validated with respect to linearity, accuracy, precision, and robustness. The method was successfully applied to the estimation of tolperisone in tablet dosage forms. U. K. Chhalotiya, K. K. Bhatt, D. A. Shah, S. L. Baldania, and S. B. Patel Copyright © 2013 U. K. Chhalotiya et al. All rights reserved. Modification of Poly(ether ether ketone) Polymer for Fuel Cell Application Tue, 03 Dec 2013 09:52:15 +0000 Polyelectrolyte membrane (PEM) is an important part of PEM fuel cell. Nafion is a commercially known membrane which gives the satisfactory result in PEM fuel cell operating at low temperature. Present research paper includes functionalization of Poly(ether ether ketone) (PEEK) polymer with phosphonic acid group. The functionalization was done with the help of nickel-based catalyst. Further, the polymer was characterized by the FTIR, EDAX, DSC, TGA, and 1H NMR, and it was found that PEEK polymer was functionalized with phosphonic acid group with good thermal stability in comparison to virgin PEEK. Finally, the thin films of functionalized polymer were prepared by solution casting method, and proton conductivity of film samples was measured by impedance spectra whose value was found satisfactory with good thermal stability in comparison to commercially available Nafion membrane. Devesh Shukla, Yuvraj Singh Negi, and Vijai Kumar Copyright © 2013 Devesh Shukla et al. All rights reserved. Naturally Occurring Xanthones: Chemistry and Biology Thu, 14 Nov 2013 13:13:42 +0000 Xanthones are one of the biggest classes of compounds in natural product chemistry. A number of xanthones have been isolated from natural sources of higher plants, fungi, ferns, and lichens. They have gradually risen to great importance because of their medicinal properties. This review focuses on the types, isolation, characterization, biological applications, and biosynthesis of naturally occurring xanthones isolated so far. Different physicochemical and instrumental methods such as liquid-solid and liquid-liquid extraction, TLC, flash chromatography, column chromatography, IR, 1H NMR and 13C NMR spectroscopy, GLC, HPLC, GC, and LCMS have been widely used for isolation and structural elucidation of xanthones. Hepatoprotective, anticarcinogenic, antileprosy, antimalarial, antioxidant, anticholinergic, mutagenicity, radioprotective, immunomodulatory, antibone resorption, antiparasitic, neuraminidase inhibitory, anticomplement, antibacterial, antifungal, algicidal, anti-HIV, cardioprotective, antitumoral, antidiabetes, antihyperlipidemic, antiatherogenic, anti-inflammatory, antiulcer, antidiabetic, hypolipidemic, analgesic, antiasthmatic, antihistaminic, antiamoebic, diuretic, antidiarrheal, larvicidal, and ovicidal activities have been reported for natural occurring xanthones. To a certain extent, this review provides necessary foundation for further research and development of new medicines. J. S. Negi, V. K. Bisht, P. Singh, M. S. M. Rawat, and G. P. Joshi Copyright © 2013 J. S. Negi et al. All rights reserved. Quantification of Benazepril Hydrochloride and Hydrochlorothiazide in Tablet Dosage Form by Simultaneous Equation Spectrophotometric Method Mon, 16 Sep 2013 14:08:03 +0000 Simple, accurate, precise, reproducible, requiring no prior separation, and economical procedures for simultaneous estimation of benazepril hydrochloride (BEN) and Hydrochlorothiazide (HCT) in tablet dosage form have been developed. Simultaneous equation method employs for estimation of both drugs in methanol at 240 nm and 270 nm as two analytical wavelengths. BEN and HCT at their respective (240 nm and 270 nm) show linearity in a concentration range of 2–12 μg/mL and 4–14 μg/mL. Recovery studies for BEN are 100.0–100.6% and 99.8–100.0% for HCT in the case of simultaneous equation method confirming the accuracy of the proposed method. The proposed method is recommended for routine analysis since it is rapid, simple, accurate and also sensitive and specific. Varsha Parmar, Usmangani Chhalotiya, Dimal Shah, Kashyap Bhatt, and Sunil Baldania Copyright © 2013 Varsha Parmar et al. All rights reserved. Synthesis, Antimicrobial, and Anti-HIV1 Activity of Quinazoline-4(3H)-one Derivatives Thu, 12 Sep 2013 10:04:46 +0000 The present investigation aims to synthesize 11 compounds of quinazoline-1 derivatives and to test their antimicrobial and anti-HIV1 activities. A quick-witted method was developed for the synthesis of novel substituted quinazolinone derivatives by summarizing diverse diamines with benzoxazine reactions, and it demonstrated the benefits of typical reactions, handy operation, and outstanding product yields. These compounds were confirmed by elemental analysis, I R, 1H NMR, 13C NMR, and mass spectra. Then antimicrobial and anti-HIV1 activities of the compounds were tested in-vitro. It was found that compounds 7–11 possessed a wide range of anti microbial and anti-HIV1 activity. K. Vijayakumar, A. Jafar Ahamed, and G. Thiruneelakandan Copyright © 2013 K. Vijayakumar et al. All rights reserved. Study of Transport Properties of Tris (hydroxymethyl)aminomethane Hydrochloride in 20% (v/v) Acetone-Water System at Tue, 20 Aug 2013 14:10:46 +0000 Viscometric properties of Tris-(hydroxymethyl)amino methane hydrochloride are measured in 20% (v/v) acetone-water system 303.15°K. The related parameters are the experimental values of viscosity () allow to determine relative viscosity (), viscosity -coefficient of the Jones-Dole equation, free energies of activation of viscous flow and per mole solvent, and solute, respectively. The excess molar volume, excess viscosity, excess Gibb’s free energy, and interaction parameter of Grunberg and Nissan have also been calculated. These studies are of great help in characterizing the structure and properties of solutions. The addition of an organic solvent to water brings about a sharp change in the solvation of ions. Ajita Dixit Copyright © 2013 Ajita Dixit. All rights reserved. Insight into Equilibrium and Kinetics of the Binding of Cadmium Ions on Radiation-Modified Straw from Oryza sativa Tue, 30 Jul 2013 08:52:22 +0000 The present study reports the chemical modification of agricultural waste (rice straw) with urea using microwave radiation and the efficiency evaluation of this modified rice straw for the adsorption of a toxic heavy metal, cadmium. The elemental analysis of urea modified rice straw affirmed urea grafting on rice straw, and FTIR spectra of chemically benign modified adsorbent showed the presence of hydroxyl, carbonyl, and amino functional groups. Effects of process parameters (adsorbent dosage, contact time, agitation speed, pH, and temperature) were studied in batch mode. Parameters were optimized for the equilibrium study, and adsorption mechanism was elucidated using five mathematical models (Langmuir, Freundlich, Temkin, Harkin-Jura, and Dubinin-Radushkevich). Binding of Cd(II) ions on modified adsorbent followed Langmuir model, and the maximum uptake capacity was found to be 20.70 mg g−1. Kinetic modeling was done using six different kinetic models. The process was considered physisorption according to the obtained activation energy value. Thermodynamic parameters confirmed the process to be favorable and feasible. Exothermic nature of adsorption of Cd(II) ions on urea modified rice straw was confirmed by the negative value of ΔH°. Sana Zulfiqar Ali, Makshoof Athar, Umar Farooq, and Muhammad Salman Copyright © 2013 Sana Zulfiqar Ali et al. All rights reserved. Performance of the Biocompatible Surfactant Tween 80, for the Formation of Microemulsions Suitable for New Pharmaceutical Processing Sun, 14 Jul 2013 10:23:49 +0000 The aim of this work was to investigate the phase behaviour and the structure of the n-hexane/water emulsions based on a nonionic, nontoxic and biocompatible surfactant, Tween 80. This system is of interest for new pharmaceutical techniques based on supercritical fluids to form nano- and encapsulated particles. However, it showed a lack of stability denoted by large areas of macroemulsion. For this reason, the effect of additives (alcohols and brine) and external variables (temperature) were explored. The replacement of water by brine caused negligible impact due to the nonionic character of Tween 80. On the contrary, the presence of an alcohol (ethanol or 1-butanol) enhanced the solubility of the surfactant in the oil phase and decreased the mixture viscosity, resulting in improved surface activity. Similar results were obtained by raising the temperature until the cloud point was reached (60°C). With these modifications, microemulsions at relatively low concentrations of surfactant (around 30%) and within a broad interval of compositions could be obtained, widening their possible use in pharmaceuticals manufacturing (such as controlled drug delivery, enzymatic reactions, or excipient processing). The understanding of the surfactant performance could be further used to substitute the n-hexane by a greener solvent, such as supercritical CO2. Cristina Prieto and Lourdes Calvo Copyright © 2013 Cristina Prieto and Lourdes Calvo. All rights reserved. Recent Development in Chemical Depolymerization of Lignin: A Review Wed, 10 Jul 2013 10:28:38 +0000 This article reviewed recent development of chemical depolymerization of lignins. There were five types of treatment discussed, including base-catalyzed, acid-catalyzed, metallic catalyzed, ionic liquids-assisted, and supercritical fluids-assisted lignin depolymerizations. The methods employed in this research were described, and the important results were marked. Generally, base-catalyzed and acid-catalyzed methods were straightforward, but the selectivity was low. The severe reaction conditions (high pressure, high temperature, and extreme pH) resulted in requirement of specially designed reactors, which led to high costs of facility and handling. Ionic liquids, and supercritical fluids-assisted lignin depolymerizations had high selectivity, but the high costs of ionic liquids recycling and supercritical fluid facility limited their applications on commercial scale biomass treatment. Metallic catalyzed depolymerization had great advantages because of its high selectivity to certain monomeric compounds and much milder reaction condition than base-catalyzed or acid-catalyzed depolymerizations. It would be a great contribution to lignin conversion if appropriate catalysts were synthesized. Hai Wang, Melvin Tucker, and Yun Ji Copyright © 2013 Hai Wang et al. All rights reserved. Arsenic Precipitation in the Bioleaching of Realgar Using Acidithiobacillus ferrooxidans Thu, 27 Jun 2013 10:41:23 +0000 The current study investigates the characteristics of arsenic precipitation during the bioleaching of realgar. The bioleaching performance of Acidithiobacillus ferrooxidans BY-3 (A. ferrooxidans) was investigated through scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectrophotometry. SEM and XRD analyses revealed that the arsenic-adapted strain of A. ferrooxidans was more hydrophobic and showed higher attachment efficiency to realgar compared with the wild strain. The arsenic precipitation using A. ferrooxidans resulted in the precipitation of an arsenic-rich compound on the surface of the bacterial cell, as shown in the TEM images. The FT-IR spectra suggested that the −OH and −NH groups were closely involved in the biosorption process. The observations above strongly suggest that the cell surface of A. ferrooxidans plays a role in the induction of arsenic tolerance during the bioleaching of realgar. Peng Chen, Lei Yan, Qiang Wang, and Hongyu Li Copyright © 2013 Peng Chen et al. All rights reserved. Thermal Decomposition Behavior of Melaminium Benzoate Dihydrate Thu, 20 Jun 2013 17:05:39 +0000 Crystals of melaminium benzoate dihydrate (MBDH) have been grown from aqueous solution by slow solvent evaporation method at room temperature. Powder X-ray diffraction analysis confirms that MBDH crystallizes in the monoclinic system (C2/c). Thermal decomposition behavior of MBDH has been studied by thermogravimetric analysis at three different heating rates: 10, 15, and 20°C/min. Nonisothermal studies of MBDH revealed that the decomposition occurs in three stages. The values of effective activation energy (Ea) and preexponential factor (ln A) of each stage of thermal decomposition for all heating rates were calculated by model free methods: Arrhenius, Flynn-Wall, Friedman, Kissinger, and Kim-Park methods. A significant variation of effective activation energy (Ea) with conversion (α) indicates that the process is kinetically complex. The linear relationship between the A and Ea values was established (compensation effect). Avrami-Erofeev model (A3), contracting cylinder (R2), and Avrami-Erofeev model (A4) were accepted by stages I, II, and III, respectively. DSC has also been performed. N. Kanagathara, M. K. Marchewka, K. Pawlus, S. Gunasekaran, and G. Anbalagan Copyright © 2013 N. Kanagathara et al. All rights reserved. Novel Oxidative Desulfurization of a Model Fuel with H2O2 Catalyzed by AlPMo12O40 under Phase Transfer Catalyst-Free Conditions Wed, 12 Jun 2013 18:01:10 +0000 A novel process was developed for oxidative desulfurization (ODS) in the absence of a phase transfer catalyst (PTC) using only Keggin heteropolyacids and their aluminum salts as catalysts. Reactions were performed in biphasic mixtures of isooctane/acetonitrile, with dibenzothiophene (DBT) as a model sulfur compound and hydrogen peroxide as the oxidant. Remarkably, only the AlPMo12O40-catalyzed reactions resulted in complete oxidation of DBT into DBT sulfone, which was totally extracted by acetonitrile, reducing the sulfur content of isooctane from the 1000 ppm to <1 ppm. Ranking of catalyst efficiency is as follows: AlPMo12O40 > H3PMo12O40 > AlPW12O40 > H3PW12O40. The absence of a PTC, acidic organic peroxides, and the use of hydrogen peroxide, an environmentally benign oxidant, make up the positive aspects of AlPMo12O40-catalyzed ODS reactions. In these reactions, high rates of DBT removal (ca. 100%) were achieved within a short time (ca. 2 hours) and under mild reaction conditions. Márcio José da Silva and Lidiane Faria dos Santos Copyright © 2013 Márcio José da Silva and Lidiane Faria dos Santos. All rights reserved.