Journal of Chemistry https://www.hindawi.com The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. Five Regioisomers of Dimethyl Dodecahedrane Derivatives: A Hybrid DFT B3LYP Study Wed, 20 Sep 2017 09:21:15 +0000 http://www.hindawi.com/journals/jchem/2017/5494038/ The hybrid density functional (B3LYP/6-31G(d, p)) method was used to understand why 1,2-dimethyl dodecahedrane has not been reported yet. From the direct dimethyl substitution of the dodecahedrane cage, we could have five C20H18(CH3)2 derivatives which were geometrically optimized without constraints. The results suggest that 1,16-dimethyl dodecahedrane derivative is the most stable, whereas the 1,2-dimethyl derivative is the most unstable; this implies that the distortion due to steric hindrance interactions would be a crucial effect on the relative energies of the dimethyl dodecahedranes. It would be disadvantaged thermodynamically for 1,2-dimethyl derivative that, in the experimental results, was not synthesized yet. The LUMO of each of the derivatives was equivalently delocalized over the void within the cage, implying that dimethyl derivatives are able to encapsulate atoms at the center of the cage. The HOMO was limitedly delocalized on the cage. The characteristics of the HOMO of derivatives show three patterns, implying that each derivative might undergo one of three entirely different sets of characteristic chemical reactions with electrophilic reagents. Seol Lee, YongJae Cho, and Kee Hag Lee Copyright © 2017 Seol Lee et al. All rights reserved. Decay Experiments of Effective N-Removing Microbial Communities in Sequencing Batch Reactors Thu, 14 Sep 2017 08:26:49 +0000 http://www.hindawi.com/journals/jchem/2017/4878910/ The temporal changes in the compositions of effective N-removing bacterial communities and the decay coefficients of Anammox were studied within the 120-day decay period under anaerobic or aerobic conditions at 25°C. The maximum nitrogen production rate (MNPR) was determined by measuring the temperature, pH, volatile suspended solids (VSSs), and nitrogen-removal efficiency of the microbial communities during the decay period. The decay coefficients under anaerobic and aerobic conditions at 25°C were determined through equation-based fitting to be 0.031 d−1 and 0.070 d−1, respectively. Through molecular biological means and together with quantitative polymerase chain reaction (qPCR), the proportions of AnAOB in the microbial communities dropped from 48.70% to 3.69% under anaerobic condition and from 48.70% to 1.98% under aerobic condition during the decay period. Chen Lv, Ming Li, Shuang Zhong, Jianlong Wang, and Lei Wu Copyright © 2017 Chen Lv et al. All rights reserved. Effect of the Organobentonite Filler on Structure and Properties of Composites Based on Hydroxyethyl Cellulose Thu, 14 Sep 2017 06:49:27 +0000 http://www.hindawi.com/journals/jchem/2017/1603937/ Organobentonite powder was synthesized and characterized using laser diffraction, X-ray diffraction, low-temperature nitrogen adsorption-desorption technique, and dynamic light scattering. Obtained powder was found as material with mesopores. The organobentonite particles were larger than pure bentonite one. Hydroxyethyl cellulose (HEC) was filled with organobentonite particles by mechanical dispersion, and produced composite films were researched by the number of methods. New data relating to structure, tensile properties, and antimicrobial activity of HEC/organobentonite composites were obtained. Using results of X-ray diffraction, the reflections assigned to crystal filler in polymer material were proved. Concentration effect of the filling agent on tensile properties of composite film was revealed. Data of infrared (IR) spectrometry indicated a decrease in the density of hydrogen-bond net in HEC/organobentonite composite as compared with pristine HEC. Using microbiological tests, it was found that the HEC/organobentonite films exhibited bacteriostatic action against S. aureus and fungistatic action against molds. Olga V. Alekseeva, Anna N. Rodionova, Nadezhda A. Bagrovskaya, Alexander V. Agafonov, and Andrew V. Noskov Copyright © 2017 Olga V. Alekseeva et al. All rights reserved. Synthesis of Propylene Carbonate from Epoxide and CO2 Catalyzed by Carbon Nanotubes Supported Fe1.5PMo12O40 Mon, 11 Sep 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/5641604/ Carbon nanotubes (CNTs) were functionalized and were then used as supports of Fe1.5PMo12O40 (FePMo) Keggin heteropolyanions catalysts. The characterization of the resulting catalysts was investigated by inductively coupled plasma spectrometry (ICP), Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), ultraviolet-visible (UV-Vis) light spectroscopy, and transmission electron microscopy (TEM). FTIR and XRD results confirmed that FePMo was bounded on CNTs successfully and the Keggin structure was preserved. Characterization by TEM showed that solids with high FePMo content exhibited aggregation of FePMo in large particles. The as-prepared catalysts were tested in the synthesis of propylene carbonate (PC) from CO2 and propylene oxide (PO) in a solvent-free reaction and under mild conditions. Effects of various parameters, such as reaction temperature, reaction time, FePMo content on the support, and catalyst loading on the reaction, were investigated. It has been found that CNTs supported FePMo achieved 57.7% PO conversion and 99.0% PC selectivity, whereas unsupported FePMo led only to 8.5% conversion and 48.6% selectivity. The remarkable enhancement of the catalytic activity over the supported catalyst can be attributed mainly to the better dispersion and reactivity of the FePMo catalyst in the supported material. Tahani Al-Garni, Nada Al-Jallal, and Ahmed Aouissi Copyright © 2017 Tahani Al-Garni et al. All rights reserved. Kinetics of Methane Hydrate Formation in an Aqueous Solution with and without Kinetic Promoter (SDS) by Spray Reactor Wed, 06 Sep 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/5208915/ Hydrate formation apparatus reported so far was mainly concentrated in stirred-tank batch environments. It was difficult to produce the high gas storage hydrate efficiently. Some nonstirred technology has been attracting more attention by researchers. This work proposed a new apparatus for hydrate formation by spraying water into a gaseous phase with a fine nozzle. It can get sufficient contact surface area for gas-liquid reaction. Methane hydrate formation experiments have been conducted using pure water and sodium dodecyl sulfate (SDS) aqueous solution for comparison at 277.15 K. The experiments were conducted at 7.0 and 6.0 MPa, respectively. Kinetics of methane hydrate formation have been investigated by methane consumption per mole of water and reaction rate. The mechanism of hydrate formation and kinetics property by spraying atomization were studied with the theory of crystal chemistry. Yaqin Tian, Yugui Li, Hongping An, Jie Ren, and Jianfeng Su Copyright © 2017 Yaqin Tian et al. All rights reserved. Modelling and Interpretation of Adsorption Isotherms Tue, 05 Sep 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/3039817/ The need to design low-cost adsorbents for the detoxification of industrial effluents has been a growing concern for most environmental researchers. So modelling of experimental data from adsorption processes is a very important means of predicting the mechanisms of various adsorption systems. Therefore, this paper presents an overall review of the applications of adsorption isotherms, the use of linear regression analysis, nonlinear regression analysis, and error functions for optimum adsorption data analysis. Nimibofa Ayawei, Augustus Newton Ebelegi, and Donbebe Wankasi Copyright © 2017 Nimibofa Ayawei et al. All rights reserved. Anthocyanin Retention of Cranberry (Vaccinium macrocarpon) Juice Subjected to Different Nanofiltration Conditions Wed, 30 Aug 2017 07:16:30 +0000 http://www.hindawi.com/journals/jchem/2017/7209243/ The aim of this work was to evaluate the retention of anthocyanin during a nanofiltration process of cranberry juice. Nanofiltration membranes, HC-50P DDS with an effective area of 0.36 m2 in a plate/frame nanofilter system, DDS Lab Module, were used for the experiments. Juice feed flow rate varied from 1.0 to 12.0 L min−1 at transmembrane pressures between 20 and 40 bar (2026 and 4052 kPa). Permeate flux reached a maximum value of 41.3 L h−1 m−2 at a pressure of 40 bar and a feed rate of 12 L min−1, showing a direct dependency on these two parameters. Retention coefficients of anthocyanin of 0.94 to 0.99 corresponding to percentage recovery between 93 and 99% were obtained. Total anthocyanin content increased to values between 237 and 287 mg L−1 from original concentration of 82 to 97 mg L−1 in feed solution. Total soluble solids were also retained on the nanofilter. Both anthocyanin retentate and permeate obtained by nanofiltration could be potential functional ingredients for the food and nutraceutical industry. Kong Ah-Hen, Marcia Costa, Susan Poo, and Roberto Lemus-Mondaca Copyright © 2017 Kong Ah-Hen et al. All rights reserved. Rheology and Microbiology of Sludge from a Thermophilic Aerobic Membrane Reactor Mon, 28 Aug 2017 09:45:33 +0000 http://www.hindawi.com/journals/jchem/2017/8764510/ A thermophilic aerobic membrane reactor (TAMR) treating high-strength COD liquid wastes was submitted to an integrated investigation, with the aim of characterizing the biomass and its rheological behaviour. These processes are still scarcely adopted, also because the knowledge of their biology as well as of the physical-chemical properties of the sludge needs to be improved. In this paper, samples of mixed liquor were taken from a TAMR and submitted to fluorescent in situ hybridization for the identification and quantification of main bacterial groups. Measurements were also targeted at flocs features, filamentous bacteria, and microfauna, in order to characterize the sludge. The studied rheological properties were selected as they influence significantly the performances of membrane bioreactors (MBR) and, in particular, of the TAMR systems that operate under thermophilic conditions (i.e., around 50°C) with high MLSS concentrations (up to 200 gTS L−1). The proper description of the rheological behaviour of sludge represents a useful and fundamental aspect that allows characterizing the hydrodynamics of sludge suspension devoted to the optimization of the related processes. Therefore, in this study, the effects on the sludge rheology produced by the biomass concentration, pH, temperature, and aeration were analysed. Alessandro Abbà, Maria Cristina Collivignarelli, Sauro Manenti, Roberta Pedrazzani, Sara Todeschini, and Giorgio Bertanza Copyright © 2017 Alessandro Abbà et al. All rights reserved. Chemical Composition of Essential Oils from Six Zanthoxylum Species and Their Repellent Activities against Two Stored-Product Insects Mon, 28 Aug 2017 07:43:08 +0000 http://www.hindawi.com/journals/jchem/2017/1287362/ The objective of this study was to analyze six essential oils from Zanthoxylum genus (family Rutaceae) in China and evaluate their repellent activities against Tribolium castaneum and Lasioderma serricorne adults. Six essential oils from Zanthoxylum genus, including Z. armatum, Z. dimorphophyllum, Z. dimorphophyllum var. spinifolium, Z. piasezkii, Z. stenophyllum, and Z. dissitum, were obtained by hydrodistillation and their yields were ranging from 0.02% to 0.53%. Totally, there were 39 chemical components revealed by GC-MS. Among them, some components with high relative content existed in more than three Zanthoxylum species. For instance, both -cadinene (1.21%–17.15%) and spathulenol (0.36%–10.19%) appeared in essential oils of Z. dimorphophyllum, Z. piasezkii, Z. stenophyllum, and Z. dissitum which were found to have higher content of sesquiterpenoids. The repellent activities of six essential oil samples against T. castaneum and L. serricorne adults were investigated for the first time. Data demonstrated that six Zanthoxylum species had much stronger repellent activities against T. castaneum than L. serricorne adults, especially in 2 hours after exposure. The results indicate that these six essential oils from Zanthoxylum have significant potential to be developed into natural repellents to control insects in grains, food, and traditional Chinese medicinal materials. Wen-Juan Zhang, Zhe Zhang, Zhen-Yang Chen, Jun-Yu Liang, Zhu-Feng Geng, Shan-Shan Guo, Shu-Shan Du, and Zhi-Wei Deng Copyright © 2017 Wen-Juan Zhang et al. All rights reserved. Physicochemical Characterization of Polysaccharides with Macrophage Immunomodulatory Activities Isolated from Red Ginseng (Panax ginseng C. A. Meyer) Wed, 23 Aug 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/3276430/ In this study, four polysaccharide fractions designated as RGP1, RGP2, RGP3, and RGP4 were isolated from red ginseng by DEAE-52 cellulose chromatography, and their macrophage immunomodulatory activities were investigated. The results revealed that the proliferation, NO production, and neutral red phagocytosis of RAW 264.7 macrophage cells in groups treated with RGP1 and RGP2 in vitro were increased significantly compared to RGP3 and RGP4. In addition, the level of TNF-α in RAW 264.7 cells was significantly increased in RGP1 and RGP2 groups. All the results consistently indicated that polysaccharide fractions RGP1 and RGP2 had strong macrophage immunomodulatory activities. Furthermore, RGP1 and RGP2 were purified by Sephadex G-100 column and RGP2 was further fractionated into a homogeneous fraction RGP2-1, with the molecular weight of 2.16 × 104 Da. The analysis of monosaccharide composition revealed that RGP1 was composed of arabinose, glucose, and galactose with a relative molecular ratio of 0.02 : 0.88 : 0.10. RGP2-1 was composed of rhamnose, arabinose, glucose, and galactose with a relative molecular ratio of 0.02 : 0.10 : 0.77 : 0.11. These results provided evidences that the neutral polysaccharide fractions RGP1 and RGP2 possessed significant immunomodulatory activity and could be explored as a promising natural immunomodulating agent applied in functional foods or medicines. Liang Zheng, Mengyue Wang, Ying Peng, and Xiaobo Li Copyright © 2017 Liang Zheng et al. All rights reserved. The Topological Variable Computation for a Special Type of Cycloalkanes Tue, 22 Aug 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/6534758/ As an efficient theoretical tool, graph theory is widely used in computing chemistry. In terms of index computation on molecular graphs, the researchers can learn the potential properties of chemical compounds, including drugs, materials, and organics. In this paper, by means of distance computation, we study the eccentric version indices of cycloalkanes which occur quite frequently in the chemical drugs and other compounds. The promising prospects of the application for the physical, chemical, medical, and pharmacy engineering are illustrated by theoretical conclusions obtained in this article. Wei Gao, Yaojun Chen, and Weifan Wang Copyright © 2017 Wei Gao et al. All rights reserved. Electrocoagulation-Adsorption to Remove Anionic and Cationic Dyes from Aqueous Solution by PV-Energy Mon, 21 Aug 2017 09:17:14 +0000 http://www.hindawi.com/journals/jchem/2017/5184590/ The cationic dye malachite green (MG) and the anionic dye Remazol yellow (RY) were removed from aqueous solutions using electrocoagulation-adsorption processes. Batch and continuous electrocoagulation procedures were performed and compared. Carbonaceous materials obtained from industrial sewage sludge and commercial activated carbons were used to adsorb dyes from aqueous solutions in column systems with a 96–98% removal efficiency. The continuous electrocoagulation-adsorption system was more efficient for removing dyes than electrocoagulation alone. The thermodynamic parameters suggested the feasibility of the process and indicated that the adsorption was spontaneous and endothermic ( and −0.009 for MG and RY, resp.). The value further indicated that the adsorption process was spontaneous (−6.31 and −10.48;  K). The kinetic electrocoagulation results and fixed-bed adsorption results were adequately described using a first-order model and a Bohart-Adams model, respectively. The adsorption capacities of the batch and column studies differed for each dye, and both adsorbent materials showed a high affinity for the cationic dye. Thus, the results presented in this work indicate that a continuous electrocoagulation-adsorption system can effectively remove this type of pollutant from water. The morphology and elements present in the sludge and adsorbents before and after dye adsorption were characterized using SEM-EDS and FT-IR. J. Castañeda-Díaz, T. Pavón-Silva, E. Gutiérrez-Segura, and A. Colín-Cruz Copyright © 2017 J. Castañeda-Díaz et al. All rights reserved. Synthesis, Characterization, and Antibacterial Activity of Diethyl 1-((4-Methyl-2-phenyl-4,5-dihydrooxazol-4-yl)methyl)-1H-1,2,3-triazole-4,5-dicarboxylate Sun, 20 Aug 2017 07:46:58 +0000 http://www.hindawi.com/journals/jchem/2017/4238360/ The compound, diethyl 1-((4-methyl-2-phenyl-4,5-dihydrooxazol-4-yl)methyl)-1H-1,2,3-triazole-4,5-dicarboxylate 2, was synthesized in high yield, through 1,3-dipolar cycloaddition reaction of 4-(azidomethyl)-4-methyl-2-phenyl-4,5-dihydrooxazole and diethyl but-2-ynedioate in the absence of a solvent. The structure of the synthesized compound was established on the basis of NMR spectroscopy (1H, 13C), X-ray crystallography, and MS data. The prepared compound was also tested in vitro for its antibacterial activity against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). The calculation of MBC/MIC ratio showed that this triazole derivative 2 had a bactericidal effect on the two strains tested. S. Boukhssas, Y. Aouine, H. Faraj, A. Alami, A. El Hallaoui, and H. Bekkari Copyright © 2017 S. Boukhssas et al. All rights reserved. Synthesis, Characterization, and Catalytic Studies of Mn(III)-Schiff Base-Dicyanamide Complexes: Checking the Rhombicity Effect in Peroxidase Studies Wed, 16 Aug 2017 07:52:14 +0000 http://www.hindawi.com/journals/jchem/2017/5465890/ The condensation of 3-methoxy-2-hydroxybenzaldehyde and the diamines 1,2-diphenylendiamine, 1,2-diamine-2-methylpropane and 1,3-propanediamine yielded the dianionic tetradentate Schiff base ligands N,N′-bis(2-hydroxy-4-methoxybenzylidene)-1,2-diphenylendiimine (H2L1), N,N′-bis(2-hydroxy-4-methoxybenzylidene)-1,2-diamino-2-methylpropane (H2L2) and N,N′-bis(2-hydroxy-4-methoxybenzylidene)-1,3-diaminopropane (H2L3) respectively. The organic compounds H2L1 and H2L2 have been characterized by elemental analysis, IR, 1H and 13C NMR spectroscopies and mass spectrometry electrospray (ES). The crystal structure of H2L2 in solid state, solved by X-ray crystallography, is highly conditioned in the solid state by two N-H•••N intramolecular interactions. The synthesis of three new manganese(III) complexes 1–3, incorporating these ligands, H2L1–H2L3, and dicyanamide (DCA), is reported. The complexes 1–3 have been physicochemically characterized by elemental analysis, IR and paramagnetic 1H NMR spectroscopy, ESI mass spectrometry, magnetic moment at room temperature and conductivity measurements. Complex 1 has been crystallographically characterized. The X-ray structure shows the self-assembly of the Mn(III)-Schiff base-DCA complex through µ-aquo bridges between neighbouring axial water molecules and also by stacking interactions, establishing a dimeric structure. The manganese complexes were also tested as peroxidase mimics for the H2O2-mediated reaction with the water-soluble trap ABTS, showing complexes 1-2 relevant peroxidase activity in contrast with 3. The rhombicity around the metal ion can explain this catalytic behaviour. Manuel R. Bermejo, Rocío Carballido, M. Isabel Fernández-García, Ana M. González-Noya, Gustavo González-Riopedre, Marcelino Maneiro, and Laura Rodríguez-Silva Copyright © 2017 Manuel R. Bermejo et al. All rights reserved. Effect of Propane and NaCl-SDS Solution on Nucleation Process of Mine Gas Hydrate Tue, 15 Aug 2017 06:59:38 +0000 http://www.hindawi.com/journals/jchem/2017/1059109/ In order to explore the method of accelerating hydration separation process to recover methane from mine gas, propane hydrate phase equilibrium was used to measure the equilibrium points of three kinds of mine gas in NaCl solution. Driving force was set as 1 MPa on this basis and high-pressure experimental apparatus of mine gas hydrate was used to carry out the nucleation kinetics experiments of mine gas hydrate for three gas samples in different concentrations of sodium chloride (NaCl) and sodium dodecyl sulfate (SDS) compound systems, which was to study the effect of propane and NaCl-SDS solution on nucleation process of mine gas hydrate. The results showed that induction time of multicomponent mine gas hydrate formation was shortened with the decrease of methane concentration and increase of propane concentration. The induction time of mine gas hydrate formation was shortened with the reduction of NaCl concentration and the increase of SDS concentration. It was found that methane and propane in multicomponent mine gas nucleated collaboratively, which simplified its nucleation process compared with the single component. NaCl has two kinds of functions. Qiang Zhang, Qiang Wu, and Hui Zhang Copyright © 2017 Qiang Zhang et al. All rights reserved. Application of Central Composite Design in the Adsorption of Ca(II) on Metakaolin Zeolite Thu, 10 Aug 2017 09:05:10 +0000 http://www.hindawi.com/journals/jchem/2017/7025073/ Metakaolin zeolite-A was synthesized from thermally activated kaolin clay and characterized by Fourier Transform Infrared Spectroscopy and X-Ray Diffraction Spectroscopy. The effects of pH (2–10), contact time (10–180 min), initial concentration (5–120 mgL−1), and dosage (0.1–2 g) and their interactions were investigated using response surface methodology following a central composite design. Optimum removal (87.70%) was obtained at pH 6, contact time 180 min, initial concentration 40.0 mgL−1, and adsorbent dosage 1.0 g by Excel Solver using the GRG solving method. The adsorption data fitted best to the Langmuir model with correlation coefficient and Chi-square value . The Freundlich isotherm gave a correlation coefficient and . The adsorption process followed the pseudo-second-order model. The calculated thermodynamic parameters showed that the adsorption process was endothermic and not thermodynamically spontaneous. The studied zeolite-A can therefore be used as a promising adsorbent for the removal of Ca(II) ions from aqueous solutions. Upenyu Guyo, Lycenter Yard Phiri, and Fidelis Chigondo Copyright © 2017 Upenyu Guyo et al. All rights reserved. Treatment and Recycling of the Process Water in Iron Ore Flotation of Yuanjiacun Iron Mine Tue, 08 Aug 2017 08:20:31 +0000 http://www.hindawi.com/journals/jchem/2017/9187436/ Coagulating sedimentation and oxidation treatment of process water in iron ore flotation of Yuanjiacun iron mine had been studied. The process water of this mine carried residual polyacrylamide (PAM), poly(diallyldimethylammonium chloride) (PDADMAC), and Ca2+ from the flotation and caused decrease of the iron flotation recovery or grade of the concentrate. The studies on high-intensity magnetic separation (HIMS) tailings for coagulating sedimentation showed that the settling performance of coagulant (named CYH) was better than that of PDADMAC. The analyses of FTIR spectra and zeta potential demonstrated that CYH is adsorbed mainly through electrostatic attraction onto HIMS tailings. Sodium hypochlorite was adopted to oxidize the residual organics in tailings wastewater. When sodium hypochlorite is at the dosage of 1.0 g/L, reaction temperature is of 20°C, and reaction time is of 30 minutes, the removal rates of PAM, COD, and Ca2+ were 90.48%, 83.97%, and 85.00%, respectively. Bench-scale flotation studies on the treated tailings wastewater indicated that the iron recovery and grade of concentrate were close to those of freshwater. Wen-li Jiang and Hai-feng Xu Copyright © 2017 Wen-li Jiang and Hai-feng Xu. All rights reserved. Ion Diffusion Behavior between Fracturing Water and Shale and Its Potential Influence on Production Mon, 07 Aug 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/5725720/ Water imbibition, conductivity measurements, and ion identification were performed to investigate ion diffusion behavior between slick water and shale for large-scale hydraulic fracturing. The results indicated that there was strong ion exchange between water and shale. The ion concentration in water increases with fracture complexity and is dependent on the salinity of fracturing fluids. This implies that fracturing effects could be forecast from flow-back fluid ion concentrations after large-scale slick water fracturing. Higher levels of ion diffusion imply the presence of larger fracturing areas and higher level of fracture density for a similar reservoir. The mechanism of ion diffusion and the corresponding effects on IOR (increased oil recovery) based on a field example are discussed. Yinghao Shen, Zhaopeng Zhu, Peng Shi, Hongkui Ge, and Zhihui Yang Copyright © 2017 Yinghao Shen et al. All rights reserved. Application and Validation of Simple Isocratic HPLC-UV-DAD Method with Dual Wavelength Detection for Ivabradine Determination and Its Application in the Study of Stress Degradation Mon, 07 Aug 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/2069571/ Ivabradine is a modern drug that selectively lowers the heart rate, improves cardiac energy balance, and reduces heart’s demands for oxygen and energy. Due to the chemical nature of ivabradine, which absorbs light at 207 nm and 286 nm, its detection was performed at two wavelengths. A Knauer C8 column was used to develop the RP-HPLC method for determination of ivabradine. The proposed method was linear from 5 to 100 µg/ml () for both wavelengths and limits of detection (LOD) and limits of quantification (LOQ) were 0.33 and 1.09 µg/ml for 207 nm and 1.19 and 3.97 µg/ml for 286 nm, respectively. After validation, the investigated method was applied to a stress degradation study. Numerous degradation products were formed from ivabradine solutions through alkaline and acid hydrolysis, oxidation, and photolysis. The largest numbers of degradation products were found in the sample exposed to 24 h radiation and alkaline hydrolysis (eight and six products, resp.). Finally, the simple method using HPLC-UV-DAD was developed and validated. Its usefulness for the monitoring of possible degradation products was demonstrated. Joanna Nowakowska, Piotr Pikul, Marcin Marszałł, and Krzesimir Ciura Copyright © 2017 Joanna Nowakowska et al. All rights reserved. Trace-Level Screening of Chemicals Related to Clandestine Desomorphine Production with Ambient Sampling, Portable Mass Spectrometry Tue, 01 Aug 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/8571928/ Desomorphine is a semisynthetic opioid that is responsible for the psychoactive effects of a dangerous homemade injectable mixture that goes by street name “Krokodil.” Desorption electrospray ionization (DESI) and paper spray ionization (PSI) are implemented on a portable mass spectrometer for the direct analysis of desomorphine and precursor reagent codeine from multiple substrates of potential relevance to clandestine drug laboratory synthesis and paraphernalia seizure. Minimal sample preparation required for analysis and portability of the instrument suggest the potential for rapid, on-site analysis of evidence, a highly desired benefit for forensic science and law enforcement practitioners. Both DESI-MS and PSI-MS can generate spectra consistent with preceding data obtained using traditional ionization methods, while demonstrating detection limits in the low- to sub-ng levels. Seth E. Hall, Adam E. O’Leary, Zachary E. Lawton, Alessandra M. Bruno, and Christopher C. Mulligan Copyright © 2017 Seth E. Hall et al. All rights reserved. Stability of Epidoxorubicin Hydrochloride in Aqueous Solutions: Experimental and Theoretical Studies Sun, 30 Jul 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/8107140/ The first-order degradation kinetics of epidoxorubicin were investigated as a function of pH, temperature, and buffers concentrations. The degradation was followed by HPLC. Buffer catalysis was observed in acetate and phosphate buffers. The pH-rate profiles were obtained at 333, 343, 353, and 363 K. The pH-rate expression was , where , , and are the second-order rate constants (mol−1 L s−1) for hydrogen ion activity and for hydroxyl ion activity, respectively, and and are the first-order constants (s−1) for spontaneous reaction under the influence of water. Epidoxorubicin demonstrates the greatest stability in the pH range 3–5. The electrostatic molecular potential orbitals HOMO-LUMO were also defined in order to determine the cause of the reactivity of particular epidoxorubicin molecule domains in solutions with various pH values. Agnieszka Sobczak, Monika A. Lesniewska-Kowiel, Izabela Muszalska, Artur Firlej, Judyta Cielecka-Piontek, Szymon Tomczak, Bolesław Barszcz, Irena Oszczapowicz, and Anna Jelińska Copyright © 2017 Agnieszka Sobczak et al. All rights reserved. Determination of Selected Polycyclic Aromatic Compounds in Particulate Matter Samples with Low Mass Loading: An Approach to Test Method Accuracy Thu, 27 Jul 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/3517457/ A miniaturized analytical procedure to determine selected polycyclic aromatic compounds (PACs) in low mass loadings (<10 mg) of particulate matter (PM) is evaluated. The proposed method is based on a simple sonication/agitation method using small amounts of solvent for extraction. The use of a reduced sample size of particulate matter is often limiting for allowing the quantification of analytes. This also leads to the need for changing analytical procedures and evaluating its performance. The trueness and precision of the proposed method were tested using ambient air samples. Analytical results from the proposed method were compared with those of pressurized liquid and microwave extractions. Selected PACs (polycyclic aromatic hydrocarbons (PAHs) and nitro polycyclic aromatic hydrocarbons (NPAHs)) were determined by liquid chromatography with fluorescence detection (HPLC/FD). Taking results from pressurized liquid extractions as reference values, recovery rates of sonication/agitation method were over 80% for the most abundant PAHs. Recovery rates of selected NPAHs were lower. Enhanced rates were obtained when methanol was used as a modifier. Intermediate precision was estimated by data comparison from two mathematical approaches: normalized difference data and pooled relative deviations. Intermediate precision was in the range of 10–20%. The effectiveness of the proposed method was evaluated in PM aerosol samples collected with very low mass loadings (<0.2 mg) during characterization studies from turbofan engine exhausts. Susana García-Alonso, Rosa María Pérez-Pastor, Víctor Archilla-Prat, David Sanz-Rivera, Enrique Rojas-García, Gaizka Aragón-Urrengoetxea, and Jesús Javier Rodríguez-Maroto Copyright © 2017 Susana García-Alonso et al. All rights reserved. Seasonal Changes and Spatial Variation in Water Quality of a Large Young Tropical Reservoir and Its Downstream River Wed, 26 Jul 2017 10:22:53 +0000 http://www.hindawi.com/journals/jchem/2017/8153246/ This study examined the water quality of the large young tropical Bakun hydroelectric reservoir in Sarawak, Malaysia, and the influence of the outflow on the downstream river during wet and dry seasons. Water quality was determined at five stations in the reservoir at three different depths and one downstream station. The results show that seasons impacted the water quality of the Bakun Reservoir, particularly in the deeper water column. Significantly lower turbidity, SRP, and TP were found during the wet season. At 3–6 m, the oxygen content fell below 5 mg/L and hypoxia was also recorded. Low -N, -N, and SRP and high BOD5, OKN, and TP were observed in the reservoir indicating organic pollution. Active logging activities and the dam construction upstream resulted in water quality deterioration. The outflow decreased the temperature, DO, and pH and increased the turbidity and TSS downstream. Elevated organic matter and nutrients downstream are attributable to domestic discharge along the river. This study shows that the downstream river was affected by the discharge through the turbines, the spillway operations, and domestic waste. Therefore, all these factors should be taken into consideration in the downstream river management for the health of the aquatic organisms. Teck-Yee Ling, Norliza Gerunsin, Chen-Lin Soo, Lee Nyanti, Siong-Fong Sim, and Jongkar Grinang Copyright © 2017 Teck-Yee Ling et al. All rights reserved. Tuning of Activated Carbon for Solvent-Free Oxidation of Cyclohexane Wed, 26 Jul 2017 09:14:13 +0000 http://www.hindawi.com/journals/jchem/2017/5732761/ Activated carbon (AC) was prepared from carbonization of phosphoric acid soaked peanut shell at 380°C under inert atmosphere followed by activation with hydrogen peroxide. The AC was characterized by SEM, EDX, FTIR, TGA, and BET surface area and pore size analyzer. The potential of AC as a catalyst for solvent-free oxidation of cyclohexane to cyclohexanol and cyclohexanone (the mixture is known as KA oil) in the presence of molecular oxygen at moderate temperature was investigated in a self-designed double-walled three-necked batch reactor. The effect of different reaction parameters/additive was optimized. The maximum productivity value (2.14 mmolg−1 h−1, without base, and 4.85 mmolg−1 h−1, with 0.2 mmol NaOH) of the desired product was achieved under optimal reaction parameters: vol 12.5 mL, cat 0.4 g, time 14 h, oxygen flow 40 mL/min (pO2 760 Torr), stirring 1100 rpm, and temp 75°C. The AC shows recyclability for multiple runs without any significant loss in activity. Thus, the AC can be an efficient catalyst, due to low cost, ease of synthesis, easy recovery, nonleaching, and recyclability for multiple uses for the solvent-free oxidation of cyclohexane. Mohammad Sadiq, Mashooq Khan, Muhammad Numan, Razia Aman, Saddam Hussain, M. Sohail Ahmad, Saima Sadiq, Muhammad Abid Zia, Haroon Ur Rashid, and Rahmat Ali Copyright © 2017 Mohammad Sadiq et al. All rights reserved. Effect of Surfactant on Growth of ZnO Nanodumbbells and Their Characterization Tue, 25 Jul 2017 08:58:55 +0000 http://www.hindawi.com/journals/jchem/2017/1728345/ We report the controlled synthesis of dumbbell shaped ZnO micro/nanostructures using anionic surfactant sodium dodecyl sulphate (SDS) by simple one-step hydrothermal method. The morphology changes of ZnO were characterized by using scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy. It is found that the size of the dumbbell increased with increase in concentration of SDS. Systematic growth mechanism with increase of concentration of SDS polymer is studied. Our results will help in the growing face selective ZnO for many functional applications. Sunil Babu Eadi, Sungjin Kim, and Soon Wook Jeong Copyright © 2017 Sunil Babu Eadi et al. All rights reserved. Synthesis and Anticancer Activities of 4-[(Halophenyl)diazenyl]phenol and 4-[(Halophenyl)diazenyl]phenyl Aspirinate Derivatives against Nasopharyngeal Cancer Cell Lines Tue, 25 Jul 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/6760413/ Aspirin and azo derivatives have been widely studied and have drawn considerable attention due to diverse biological activities. In this study, a series of 4-[(halophenyl)diazenyl]phenyl aspirinate derivatives were synthesized from the reaction of aspirin with 4-[(halophenyl)diazenyl]phenol via esterification, in the presence of DCC/DMAP in DCM with overall yield of 45–54%. 4-[(Halophenyl)diazenyl]phenol was prepared prior to esterification from coupling reaction of aniline derivatives and phenol in basic solution. All compounds were characterized using elemental analysis, FTIR, and 1H and 13C NMR spectroscopies. All compounds were screened for their anticancer activities against nasopharyngeal cancer (NPC) HK-1 cell lines and the viability of cultured cells was determined by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxylmethoxylphenyl)-2-(4-sulfophenyl)-2H-tetrazolium]-based colorimetric assay. 4-[(E)-(Fluorophenyl)diazenyl]phenol showed the highest anticancer activity against NPC HK-1 cell lines compared to other synthesized compounds. 4-[(Halophenyl)diazenyl]phenyl aspirinate showed low cytotoxicity against NPC HK-1 cell lines compared to 4-[(halophenyl)diazenyl]phenol but better anticancer activity than aspirin alone. Boon Kui Ho, Zainab Ngaini, Paul Matthew Neilsen, Siaw San Hwang, Reagan Entigu Linton, Ee Ling Kong, and Boon Kiat Lee Copyright © 2017 Boon Kui Ho et al. All rights reserved. Antifungal Activity of New Eugenol-Benzoxazole Hybrids against Candida spp. Mon, 24 Jul 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/5207439/ Eugenol is a natural allylphenol responsible for a wide range of biological activities, especially antimicrobial. Benzoxazoles are heterocycles with recognized antimicrobial activities. This paper describes the design, synthesis, and the biological results for benzoxazole type derivatives of eugenol as antifungal agents. The products were obtained in good yields by a four-step synthetic sequence involving aromatic nitration, nitroreduction, amide formation, and cycle condensation. They were evaluated against species of Candida spp. in microdilution assays, and four products (5a, 5b′, 5c, and 5d′) were about five times more active than eugenol against C. albicans and C. glabrata. Two of them (5b′ and 5d′) showed good activity against C. krusei, a species which is naturally resistant to fluconazole. Furthermore, the active products were more selective than eugenol against human blood cells, showing that they are interesting substances for further optimization. Larissa Incerti Santos de Carvalho, Dalila Junqueira Alvarenga, Letícia Cruz Ferreira do Carmo, Lucas Gomes de Oliveira, Naiara Chaves Silva, Amanda Latércia Tranches Dias, Luiz Felipe Leomil Coelho, Thiago Belarmino de Souza, Danielle Ferreira Dias, and Diogo Teixeira Carvalho Copyright © 2017 Larissa Incerti Santos de Carvalho et al. All rights reserved. Novel Thiazole Derivatives of Medicinal Potential: Synthesis and Modeling Mon, 24 Jul 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/4102796/ This paper reports on the synthesis of new thiazole derivatives that could be profitably exploited in medical treatment of tumors. Molecular electronic structures have been modeled within density function theory (DFT) framework. Reactivity indices obtained from the frontier orbital energies as well as electrostatic potential energy maps are discussed and correlated with the molecular structure. X-ray crystallographic data of one of the new compounds is measured and used to support and verify the theoretical results. Nour E. A. Abdel-Sattar, Abeer M. El-Naggar, and M. S. A. Abdel-Mottaleb Copyright © 2017 Nour E. A. Abdel-Sattar et al. All rights reserved. Response Surface Methodology for Biodiesel Production Using Calcium Methoxide Catalyst Assisted with Tetrahydrofuran as Cosolvent Wed, 19 Jul 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/4190818/ The present study was performed to optimize a heterogeneous calcium methoxide (Ca(OCH3)2) catalyzed transesterification process assisted with tetrahydrofuran (THF) as a cosolvent for biodiesel production from waste cooking oil. Response surface methodology (RSM) with a 5-level-4-factor central composite design was applied to investigate the effect of experimental factors on the percentage of fatty acid methyl ester (FAME) conversion. A quadratic model with an analysis of variance obtained from the RSM is suggested for the prediction of FAME conversion and reveals that 99.43% of the observed variation is explained by the model. The optimum conditions obtained from the RSM were 2.83 wt% of catalyst concentration, 11.6 : 1 methanol-to-oil molar ratio, 100.14 min of reaction time, and 8.65% v/v of THF in methanol concentration. Under these conditions, the properties of the produced biodiesel satisfied the standard requirement. THF as cosolvent successfully decreased the catalyst concentration, methanol-to-oil molar ratio, and reaction time when compared with biodiesel production without cosolvent. The results are encouraging for the application of Ca(OCH3)2 assisted with THF as a cosolvent for environmentally friendly and sustainable biodiesel production. Nichaonn Chumuang and Vittaya Punsuvon Copyright © 2017 Nichaonn Chumuang and Vittaya Punsuvon. All rights reserved. Adsorptive Removal of Benzene and Toluene from Aqueous Environments by Cupric Oxide Nanoparticles: Kinetics and Isotherm Studies Tue, 18 Jul 2017 00:00:00 +0000 http://www.hindawi.com/journals/jchem/2017/2069519/ Removal of benzene and toluene, as the major pollutants of water resources, has attracted researchers’ attention, given the risk they pose to human health. In the present study, the potential of copper oxide nanoparticles (CuO-NPs) in eliminating benzene and toluene from a mixed aqueous solution was evaluated. For this, we performed batch experiments to investigate the effect of solution pH (3–13), dose of CuO-NPs (0.1–0.8 g), contact time (5–120 min), and concentration of benzene and toluene (10–200 mg/l) on sorption efficiency. The maximum removal was observed at neutral pH. By using the Langmuir model, we measured the highest adsorption capacity to be 100.24 mg/g for benzene and 111.31 mg/g for toluene. Under optimal conditions, adsorption efficiency was 98.7% and 92.5% for benzene and toluene, respectively. The sorption data by CuO-NPs well fitted into the following models: Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich model. The experimental information well fitted in the Freundlich for benzene and Langmuir for toluene. Based on the results, adsorption followed pseudo-second-order kinetics with acceptable coefficients. The findings introduced CuO-NPs as efficient compounds in pollutants adsorption. In fact, they could be used to develop a simple and efficient pollutant removal method from aqueous solutions. Leili Mohammadi, Edris Bazrafshan, Meissam Noroozifar, Alireza Ansari-Moghaddam, Farahnaz Barahuie, and Davoud Balarak Copyright © 2017 Leili Mohammadi et al. All rights reserved.