Showing papers in "Journal of Advances in Chemistry in 2018"

Studies on Biodiesel Synthesis Using Nanosilica Immobilised Lipase in Inverse Fluidized Bed Bioreactors

Abstract: Biodiesel synthesis from neem oil and methyl acetate using lipase catalyst immobilised in nanosilica particles in a continuous inverse fluidised bed bioreactor of modified design has been analysed. The process has been simulated mathematically by developing a multiparameter software package and subsequently verified through pilot plant tests(experiments).The improved performance characteristics of the bioreactor of proposed design have been highlighted. Graphical data have been presented to illustrate the dependence of reactor performance on system/operating parameters such as substrate flow rate, catalyst loading and molar ratio of oil to acetate in the blend(substrate solution).The downflow mode of operation is an added advantage of these bioreactors which tends to reduce their operating cost. Due to the use of nanoparticles, the effectiveness factor is close to unity and consequently, the global rate of transesterification is more or less equal to the intrinsic rate. This enhances the performance efficiency of the bioreactor.

Direct Spectrophotometric Determination of Cefuroxime Axetil in Pure Form and Pharmaceutical Dosage Forms.

Abstract: A simple, direct and cost-effective spectrophotometric method for determination of cefuroxime axetil (CRXA) in pure and tablet dosage forms was applied. This method is based on formation of ion-pair complex ([CRXA]:[BTB]) between CRXA and bromothymol blue (BTB) in chloroform. Beer’s law in the optimum experimental conditions using [CRXA]:[BTB] complex is valid within a concentration range of 2.00-50.00 ?M (1.021–25.524 ?g.mL-1). The developed method is applied for the determination of CRXA in pure and its commercial tablets without any interference from excipients with average assay of 96.8 to 101.6% and the results are in good agreement with those obtained by the HPLC reference method. Associated drugs (sulbactam and linesolid) with cefuroxime axetil are considered to be interfere, while metronidazole can be considered as non-interfere.

Modification of Acetyl Acetone with Methyl Acrylate

Abstract: Acetyl acetone was modified by a KF/alumina mediated Michael addition reaction under solventless condition with methyl acrylate. Methyl acrylate formed single and double addition with the acetyl acetone. The optimal temperature for this reaction was 393 K. The modified I²-diketones were confirmed using GC-FID and GC-MS. The products could be tested as metal chelating agents and in related applications.

Optimization of 6-Gingerol Extraction Assisted by Microwave From Fresh Ginger Using Response Surface Methodology

Abstract: The present study investigates optimum conditions for Microwave assisted extraction (MAE) of 6-gingerol. Ginger was dried using a cross flow dryer at 55 ± 2 0C for eight hours. Ginger powder was extracted at three different watts (400 W, 500 W, and 600 W), temperatures (50 0C, 60 0C, 70 0C) and time (10, 20, 30 min) for optimum yield. 6-gingerol content was found to be 21.15 ± 0.13 and 18.81 ± 0.15 mg/g in fresh ginger and dried ginger, respectively. Optimized condition obtained by RSM for 6-gingerol was 400 W, 70 0C at 10 min extraction time. The results of MAE are expressed by 2-D contour plot and response surface curve by keeping one variable constant which showed highest yield at 600 W, 70 0C for 30 min extraction time. Microwave assisted extracts exhibited higher antioxidant activity in comparison with conventional extracts.

Direct Spectrophotometric Determination of Glimepiride in Pure Form And Pharmaceutical Formulations Using Bromocresol Purple

Abstract: A simple, direct and accurate spectrophotometric method has been developed for the determination of Glimepiride (GLM) in pure and pharmaceutical formulations by complex formation with bromocresol purple (BCP). The method involves the formation of a yellow ion-pair complex between BCP with glimepiride at pH<3,8; after reacting GLM with Na2CO3 to give C24H33N4H+O5NaS which is extracted by chloroform. The formed complex [GLM]:[ BCP] was measured at lmax 418 nm against the reagent blank prepared in the same manner. Variables were studied in order to optimize the reaction conditions. Molar absorptivity (e) for complex was 20600 L.mol-1.cm-1. Beer’s law was obeyed in the concentration range of 1.226 – 46.608 mg.mL-1 in present of 5.0x10-4 mol/l of BCP with good correlation coefficient (R2= 0.9997). The relative standard deviation did not exceed 3.6%. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.15 and 0.46 mg.mL-1, respectively. The proposed method was validated for specificity, linearity, precision and accuracy, repeatability, sensitivity (LOD and LOQ) and robustness. The developed method is applicable for the determination of GLM in pure and different dosage forms with average assay of 98.8 to 102.0% and the results are in good agreement with those obtained by the RP-HPLC reference method.

Issues on Design of Piled Raft Foundation

Abstract: A piled raft foundation consists of a thick concrete slab reinforced with steel which covers the entire contact area of the structure, in which the raft is supported by a group of piles or a number of individual piles. Bending moment on raft, differential and average settlement, pile and raft geometries are the influencing parameters of the piled raft foundation system. In this paper, a detailed review has been carried out on the issues on the raft foundation design. Also, the existing design procedure was explained.

Aspartic Acid as Corrosion Inhibitor of Mild Steel Corrosion Using Weight Loss, Acidimetry and EIS Measurement

Abstract: Corrosion inhibition characteristics of aspartic acid on mild steel corrosion in 0.5 M H2SO4 was investigated using weight loss, acidimetry, and electrochemical impedance spectroscopy (EIS). Analysis of the metal surface morphology, uninhibited and inhibited, was carried out through scanned electron microscope. The results showed that the inhibition efficiency increased with increase in inhibitors concentration and rise in temperature for all methods used. The highest v efficiency of 32.36 %, 66.26 % and 80.40 % were obtained for weight loss, acidimetry and EIS, respectively. The low value of efficiency for weight loss compared to other methods should signify the limitation for the method. The increase in efficiency with rise in temperature is a feature of chemical adsorption, which was confoirmed by the value of parameter b of the Adejo-Ekwenchi adsorption isotherm (AEI) model. Values of free energy of adsorption, ?Gads were all negative for all the methods, which means the adsorption processes were spontaneous. The heats of adsorption, Qads values were all positive, implying that the processes were endothermic. Values of activation energy were fairly constant, which is an evident to support the proposed chemical adsorption mechanism. The negative sign in the values of entropy of adsorption, ?Sads is an indication that the activated complex in the rate-determining step was associative. The data obtained was tested with several isotherms, but found to best fit into the El-Awady, Freundlich and Tempkin adsorption isotherm models.

The Effect of Sodium Hydroxide Solutions with Different Ph on the Corrosion Of Iron Alloy (C1010) In Industrial Water

Abstract: The effect of increasing pH value in the corrosion of iron alloy type (C1010) was studied in the presence of different pH solutions of sodium hydroxide dissolved in industrial water at 35EsC and it was found that the corrosion rate of iron alloy was less at pH of 9.5 . This result was proved by measuring some thermodynamic parameters such as corrosion current and covered surface area that pertain to corrosion using weight loss electrical (Tafel plot ) methods . Also the effect of temperature on the rate of corrosion at ( 25EsC , 35EsC and 45EsC ) at different pH was studied and it was found that the rate of corrosion is increased with increasing the temperature at the same pH.

The Ongoing Study of the Chemistry of the Marine Inhabitants of The Ramsar Site of Port Royal, Jamaica

Abstract: Research efforts to examine the chemistry of marine organisms collected from the Ramsar site of Port Royal, Jamaica, has led to the isolation of a range of compounds as diverse as the species from which they were derived. Six sponges, two algal species, one ascidian and one soft coral collected from the mangrove area and the shallow coastal reefs were studied to yield compounds including steroids, aromatic compounds and terpenoids.

Removal of Toxic Chemicals and Biological Pollutants from Groundwater Wells Using Modified Downflow Hanging Sponge Reactor

Abstract: Water pollution is one of the most important environmental problems in the world. In developing countries, contaminated water has frequently caused water diseases. Today, water borne toxic chemicals (anions and heavy metal ions) and biological pollutants pose a great threat to the safety of water supplies. Currently, the quality of groundwater with respect to pollutants is of great concern. Modified Downflow Hanging Sponge (DHS) reactor will be a good groundwater treatment technology in the near future, it is used for excellent removal of heavy metals, anions, organic pollutants and harmful microbes, and also the reactor has advantages like low cost, easy to apply and satisfaction level. In order to achieve these objectives, treatment scheme has been investigated. It consists of mixing organic chelator with impure groundwater in different concentrations followed by a downflow hanging sponge (DHS) reactor. In the presence of 0.5 g/L of the chelator, the average removal of total NO3 and NO2 and (total dissolved solids) TDS are respectively 72%, 62% and 75%. The results show that, when Cd treated with chelator, the amount decreases from 0.0063 to 0.0 mgL -1 (100%) after 1 h, Cu decreases from 0.0023 to 0.0 mgL -1 (100%) after 1 h, Fe decreases from 0.4 to 0.0 mgL -1 (100%) after 1 h, Mn decreases from 0.3 to 0.0 mgL -1 (100%) after 1 h and Zn decreases from 0.012 to 0.0 mgL -1 (100%) after 1 h. Also, the results show removal of fecal coliform . Decreased from 50 to 0 and the overall removal efficiency of fecal coliform is (100%).

Detection and Classification of Leukemia using MPFCM Segmentation and Random Forest with Boosting Techniques

Abstract: Identification of blood disorders is through visual inspection of microscopic blood cell images. From the identification of blood disorders lead to classification of certain diseases related to blood. We propose an automatic segmentation method for segmenting White blood cell images. Firstly, modified possibilistic fuzzy c-means algorithm is proposed to detect the contours in the image. The GLCM features are extracted and features are selected by MRMR. Adaptive boosting and LS Boosting has been utilized to classify blast cells from normal lymphocyte cells. Comparison performance of classification accuracy was carried out. The effectiveness of the classification system is tested with the total of 80 samples collected. The evaluated results demonstrate that our method outperformed the existing systems with an accuracy of 88 %.

Synthesis , Characterization and Biological activity of new derivatives of Chromen-2-one

Abstract: We report the organic syntheses of new derivatives from Chromen-2-one and their antibacterial activity. Compounds 4-[Acetyl-(2-oxo-2H-chromen-4-yl)-amino]- benzenesulfonyl chloride 1a, 4-[Acetyl-(2-oxo-3-phenylsulfamoyl-2H-chromen-4-yl)-amino]-benzenesulfonyl chloride 2a , 2-{4-[Acetyl-(4-chlorosulfonyl-phenyl)-amino]-2-oxo-3-phenylsulfamoyl-2H-chromen-7-ylamino}-benzoic acid 3a. All Structures have been synthesized and characterized using melting points , IR spectra , 1H-NMR, 13C-NMR spectra , and elemental analyses . The purified synthesized compounds (1a,2a,3a), at contcentrations 2,3,5 mg/ml was tested for their antibacterial activity against three bacterial cultures ;Staphylococcus aureus, Escherchia coli and Bacillus cereus. The antibacterial activity of synthesized compounds are compared with antibacterial activity of standard antibiotics cephalexine and streptomycine. The compounds (1a,2a,3a) shows different bacteriostatic and bacteriocidal activity.

Differential Pulse Anodic Stripping Voltammetric Analysis for Determination Selenium (IV) in Bulk and in Dosage Formulations Using Multi-Modified Gold Electrode With a Mixture of O-Phenylenediamine and 2,3-Diaminonaphthalene-Nafion

Abstract: The effect of gold electrode modified with 2,3-Diaminonaphthalene (GEMDANN) or multi-modified or a mixture 2,3-diaminonaphthalene and o-phenylenediamine -nafion (GEMDAN-OPDAN) on determination of selenium (IV) using differential pulse anodic stripping voltammetric analysis (DPASVA) has been studied. Various parameters (electrolyte, deposition time, pulse duration, pulse amplitude, etc.) are affecting determination of the Se(IV) in HClO4 (0.2 M) at pH 0.22 were examined. Under the optimum conditions, liner calibration graph, Ip=f(CSe4+), were obtained in the concentration ranges of 5x10-8 - 1x10-6 M (3.948 -78.96 ng.mL-1 ) with relative standard deviations (RSD) 4.2% and detection limit 0.056 ng.mL-1, and 1x10-9 -1x10-6 M (0.07896 -78.96 ng.mL-1 ) with relative standard deviations (RSD) 4.9% and detection limit was 0.014 ng.mL-1 on GEMDANN and GEMDAN-OPDAN, respectively. This method showed a good accumulation efficiency for selenium and good resistance to interferences from metal ions as well as those associated with selenium in pharmaceuticals. The results for the determination of Se4+ using GEMDAN-OPDAN (multi-modified) were more sensitive (about 50 times) than that obtained using GEMDANN.

Textiles Printing Using Microencapsulated Pigments in Biodegradable Thickeners

Abstract: Micro-encapsulated pigments were formulated into biodegradable printing pastes and their properties were analyzed. The pigment was used as the core material and polylactic-based biodegradable thickener was used as the wall-former. Cotton/polyester blend fabric was printed with micro-encapsulated pigment using screen-printing technique without dispersing agents, penetrating agents, leveling agents or other auxiliaries. Micro-encapsulated pigment has been characterized in terms of average particle size and size distribution, morphological structure and elemental composition using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The variations in viscosity and paste stability were observed upon storing over 7 days at ambient temperature. For permanence, the micro-encapsulation process afforded better colorfastness properties against light, washing, rubbing, and perspiration.

Adsorption Of No3--N And Po43--P in Aqueous Solution Using Granular Activated Charcoal (Gac)

Abstract: In this study, adsorption of NO3- -N and PO43--P on granular activated charcoal (GAC) was investigated depending on pH, agitation time, GAC dosage, adsorption capacity and adsorption isotherms by employing batch adsorption type. The GAC was characterized by thermogravimetric analysis (TG-DTA), scanning electron micrograph coupled with energy-dispersive X-ray spectroscopy (SEM-EDX) and BET surface area analyzer. The GAC exhibited nearly similar adsorption equilibrium time. Both NO3--N and PO43—P appeared to approach equilibrium after approximately 4 h of agitation time. In the adsorption equilibrium, the removal efficiencies of NO3- -N and PO43--P were found to be 14.6-66.0 % and 52.4-99.0 %, respectively. The adsorption data for NO3--N and PO43--P was correlated to Freundlich and Langmuir isotherm model and the equilibrium data was fitted well to the Langmuir isotherm model due to their higher correlation coefficient (R2) value. The Langmuir adsorption capacity was 1.54 and 2.56 mg g-1 for NO3--N and PO43--P, respectively, which suggests that the GAC is a good adsorbent for removal of NO3--N and PO43—P from water.

Thermal Decomposition of 3,6-Diphenyl-1,2,4,5-Tetroxane in Nitromethane Solution

Abstract: The thermal decomposition reaction of benzaldehyde diperoxide (DFT; 0.001 mol L-1) in nitromethane solution studied in the temperature range of 130.0-166.0 °C, follows a first-order kinetic law up to at least 60% DFT conversion. The organic products observed were benzaldheyde and benzoic acid. A stepwise mechanism of decomposition was proposed where the first step is the homolytic unimolecular rupture of the O-O bond. The activation enthalpy and activation entropy for DFT in nitromethane were calculated (DH# = 106.3 ± 1.0 kJ mol-1 and DS# = -58.6 ± 1.1 J mol-1K-1) and compared with those obtained in other solvents to evaluate the solvent effect.

Comparison Of Fe(II) And Fe(III)-Hydralazine Complexes, A Potentiometric And Spectrophotometric Studa

Abstract: Iron in oxidation states (+2 and +3) is very essential element for human body, and its concentration significantly altered in cardio vascular disease. So the aim of the present work is to study the interaction of Fe(II) and Fe(III) with very commonly used antihypertensive drug hydralazine through potentiometric and spectrophotometric methods. The objectives of the work is to study the stoichiometry, behavior of the complexes in aqueous solution, effect of pH and behavior of this drugs towards both oxidation states of Iron. Both methods show that hydralazine forms a stable complex with both oxidation states of the metal, but the nature of complex changes with change in pH, ligand concentration and with time span. Both methods confirms 1:2 stoichiometry for Fe(II)-Hydralazine while 1:3 for Fe(III)-Hydralazine. Stabilities of both complexes were also calculated. For Fe(II)-Hydralazine complex values of log β1 and log β2 were found to be 4.99 and 7.58 respectively. For Fe(III)-Hydralazine complex log β1, log β2 and log β3 values were found to be 2.74, 7.39 and 11.32 respectively. At high ligand concentration hydralazine also show reducing properties. The study suggests a strong interaction of hydralazine with iron; however the nature of interaction is different with both oxidation states of iron.

New Compounds Measured by Fluorescence Spectroscopy. Amino-Fluorene-Thiophene Derivatives to Be Proposed as Polarity Indicators.

Abstract: The solvatochromic effect is high in conjugate compounds and easy to observe by the colour change emitted when the solutions are exposed to UV light. It was found in a series of aminofluorene thiophene derivatives, previously synthesized, that irradiating at different wavelengths, the same pattern is obtained, i.e. a dual behaviour in the solvatochromism of the studied compounds. For each one, a bathochromic and hypsochromic effect exists, in polar and nonpolar solvents, respectively. Wavelength vs. polarity index plots clearly showed the abovementioned dual behaviour as well as the improved linearity in its plots. Amidst the wavelengths at which each compound is excited in each solvent, 280 nm was selected as the fixed wavelength for the measurements; (E)-9,9-diethyl-N-hexyl-N-phenyl-7-(2-(thiofen-2-yl)vinyl)-9H-fluoren-2-amine (M6-6) exhibits better linearity as compared to the other studied compounds, being the best to be proposed as polarity sensor or indicator.

Sorption of Ni(II) and Cr(III) ions by the Chironomus yoshimatsui larvae from wastewater

Abstract: In this study, Chironomus yoshimatsui larvae were applied to remove Ni(II) and Cr(III) ions from wastewater. The sorption studies were carried out using laboratory-reared C. y. larvae. It was found that C. y. larvae are very susceptible to Cr(III) as compared to Ni(II). The survival capacity of C. y. larvae was sharply reduced when exposed to even low Cr(III) concentration. Sorption isotherm and kinetics of C. y. larvae for Ni(II) were determined by means of controlled experiments in a batch system. It was observed that sorpyion efficiency of Ni(II) was largely concentration dependent and more effective at lower concentration. At each equilibrium, Ni(II) was removed up to roughly 44∼80 %. Sorption data were better fitted to the Langmuir isotherm model because of its correlation coefficient R2 value greater than that of the Freundlich isotherm model. The sorption kinetics by C. y. larvae for Ni(II) was well described a pseudo-first-order rate expression. C. y. larvae have enormous potential for application in wastewater treatment technologies because they are widespread and abundant all around the world and can be easily kept in culture.

The Spectroscopic and theoretical investigations of complex formation of (3E,3'E)-7,7'-(carbonylbis(azanediyl))bis(3-(2-(2-hydroxyphenyl)hydrazono)-4-oxo-3,4-dihydronaphthalene-2-sulfonic acid) with metal cations

Abstract: A novel azo-dye was isolated by a diazo-coupling reaction and characterized by the elemental analysis, mass spectra, IR and UV-VIS spectroscopy. The processes of complex formation of H4L with some mono-, bis-, and trivalent metal cations were studied by spectrophotometric titration and theoretical modeling. The NBO effective charge calculations indicate a strong covalent character of the coordination bonds at complexation.

Differential Pulse Polarographic Behavior and Quantification of the Flucloxacillin in Pure and Pharmaceutical Dosage Forms Using a Static Mercury Drop Electrode

Abstract: Differential pulse polarographic analysis (DPPA) by using static mercury drop electrode (SMDE) for quantification of flucloxacillin (FLUX) in pure and pharmaceutical dosage forms was studied. The optimum conditions for the polarographic signal were determined and a study was made of the different parameters affecting the electrochemical process. The best definition of the analytical signals was found in Britton–Robinson buffer (0.06 M) at pH 4.0 . Under the optimum conditions, liner calibration graph, Ip=f(CFLUX) was obtained in the concentration ranges of 0.1 mM (0.0494 ?g.mL-1) to 26 mM (12.8414 ?g.mL-1) at -940 to -1000 mV (versus Ag/AgCl) with relative standard deviations (RSD) did not exceed 2.4% for the concentrations of FLUX (0.0494 ?g.mL-1). Regression analysis showed a good correlation coefficient (R2=9998) between Ip and concentration over the mentioned range. The limit of detection (LOD) and the limit of quantification (LOQ) were to be 0.0040 and 0.0120 ?g.mL-1, respectively. The proposed method was validated for linearity, precision and accuracy, repeatability, sensitivity (LOD and LOQ), robustness and specificity. The developed method is applicable for the determination of FLUX in pure and different dosage forms in presence a same amount of amoxicillin (AMOX) with average recovery of 99.4 to 102.2 % and the results are in good agreement with those obtained by the HPLC reference method.

Physicochemical Parameters Of Effluents From A Lubricating Oil Company And Metal Analysis Of The Sediment Of The Receiving Stream In Osogbo Osun State, Nigeria

Abstract: Effluent and its receiving sediment samples were collected on seasonal basis, comprising of three months (August to October, 2014) in the wet season and three months (December 2014 to February 2015) in the dry season. Five sampling points around the lubricating oil company were marked for the study. Physicochemical parameters of the effluent samples such as pH, temperature, conductivity, total dissolve solids were determined in situ. Dissolved oxygen and biochemical oxygen demand were determined by Winkler´s method. Digestion of the sediments was carried out by acid dissolution. The heavy metals (Mn, Ni, Co, Cd and Pb) level was determined using Flame Atomic Absorption Spectrophotometer. The results revealed that the physicochemical parameters ranged between (27.40 to 29.860C) for temperature, pH (6.89 to 7.88), electrical conductivity (92.27 to 292.84µs/cm), total dissolve solids, dissolved oxygen (2.58 to 7.01mg/L), biochemical oxygen demand (5.00 to 14.00mg/L) for the sampling periods. The overall total metal was in similar order: Mn > Ni > Co > Cd > Pb for both seasons. Most of the results were within the recommended limit required except for the levels of biochemical oxygen demand which exceeded the recommended value of 10mg/L in dry season by WHO, (2006). Statistically, no significant difference at p ≤ 0.05 between the parameters obtained in both seasons. The study concluded that the effluents discharged from the lubricating oil company in osogbo was polluted based on the results of biochemical oxygen demand and the Cd concentrations in the sediment samples.