Showing papers in "Journal of Advances in Chemistry in 2014"

Determination of Adsorption Isotherm model best fit for methanol leaf extract of Securinega virosa as corrosion inhibitor for corrosion of mild steel in HCl

Abstract: The adsorption isotherm model best fit of the methanol leaf extract of Securinega virosa as corrosion inhibitor for the corrosion of mild steel in 2 M HCl medium was determined with the assistance of the Adejo-Ekwenchi adsorption isotherm. The corrosion inhibition study was carried out using the weight loss method at the temperature range of 301 K to 313 K. The inhibition efficiency, %IE, of the extract was found to increase with increase in both concentration and temperature. On the account of, R 2 this adsorption process well fitted into Langmuir, Freundlich, Temkin isotherm, Flory-Huggins and Adejo-Ekwenchi models. However, through the parameter b of the Adejo-Ekwenchi isotherm, which clearly shows the adsorption process to be chemisorption, the best isotherm fit for the extract has been resolved to be the Langmuir isotherm and Temkin isotherm models.

Geometric-arithmetic Index and Zagreb Indices of Certain Special Molecular Graphs

Abstract: In this paper, we determine the Geometric-arithmetic indexand Zagreb indicesof fan molecular graph, wheel molecular graph, gear fan molecular graph, gear wheel molecular graph, and their r -corona molecular graphs.

Natural areca fiber: surface modification and spectral studies

Abstract: At present natural fibers are gaining tremendous progressive importance as renewable, light weight, strong, environmentally acceptable and biodegradable reinforcement material for composite preparation as automobile industry is currently shifting to “green” outlook, as consumers are looking for environmentally friendly vehicles. An important disadvantage of natural fibers is its polar nature which in turn results in weak interfacial bonding between the fibers and the matrix. This in turn leads to the inferior properties to the natural fiber reinforced polymer composites. This defect can be remedied by chemical modification of natural fibers because this chemical modification will make the natural fibers to become less hydrophilic and thus it gives a strong compatibility between the fiber and matrix. In this research work, areca fibers were subjected to various chemical treatments such as mercerization, permanganate treatment, benzoylation, acrylation and acetylation. The structure and properties of cellulose, hemicellulose, lignin and pectin present in natural fibers have been discussed. Chemical reactions of areca fibers have been discussed and FTIR and SEM images of untreated and chemically treated areca fibers were analyzed.

Protective effect of Ruta Chalepensis L. extract on oxidative stress and liver-kidney function induced by polymicrobial sepsis in rats

Abstract: Sepsis, a systemic inflammatory disease developed after an infectious insult and remains the major cause of death in intensive care units. The aim of this study was to examine the protective effect of the ethanolic extract of Ruta chalepensis L. (ERC) against oxidative stress and liver-kidney functions in cecal and ligation puncture (CLP) rats. In vitro, the results showed that ERC rich in phenolic compounds possessed important antioxidant activity. In vivo, CLP-induced oxidative stress evidenced by the increase of the TBARS and decrease in the enzymatic antioxidants (SOD, CAT, GPX) in liver and kidney. Moreover, CLP induced liver-kidney toxicities showed by an increase in the ALT, AST, PAL, LDH, BUN and creatinine in the plasma. However, the administration of ERC to CLP-rats prevents all these disorders. Positive action of ERC was confirmed by histo-pathological examination. Therefore this study suggests that ERC could be a potential therapeutic agent for sepsis treatment.

New Glass Compositions Based on Calcium-Fluoroaluminosilicate for dental composite

Abstract: The new inorganic Calcium fluoroaluminosilicate samples M1-M10 were prepared and their physical properties such as X-ray, FTIR, BET and SEM were studied and were successfully used in dental filling of light cured composite type. The optimum ratio of the new filler components was also studied to match the comparable properties of the commercial composite filling, the successful application of the prepared fillers together with high tensile strength, high compressive strength and other properties indicate the useful use of this powder mixture in light cured type composite.

In vitro Antidiabetic, anti-obesity and antioxidant proprities of Rosemary extracts

Abstract: Diabetes mellitus is a serious health problem worldwide that has adverse and long-lasting consequences for individuals, families, and communities. Hence, this study sought to investigate the inhibitory potential of rosemary extracts on key-enzymes related to diabetes such as α-amylase and pancreatic lipase activities, as well as to assess their antioxidant properties in vitro. The IC 50 values of Rosemary essential oil, ethyl acetate and methanolic extracts against α-amylase were 28.36, 34.11 and 30.39 µg/mL respectively, and those against pancreatic lipase were 32.25, 36.64 and 34.07 µg/mL, suggesting strong anti-diabetic and anti-obesity effects of Rosemary. The methanolic extract was found to be the highest in levels of phenolic (282.98 µgGAE/mg extract) and flavonoids (161.05 µg QE /mg extract) contents as well as in the antioxidant activity (IC 50 = 15.82 µg/mL) as compared to other extracts ethyl acetate (IC 50 = 32.23 µg/mL) and essential oil (IC 50 = 96.12 µg/mL). Antioxidant efficacy of Rosemary extracts has been estimated in the stabilization of sunflower oil (SFO) at three different concentrations, i.e. 200 (SFO-200), 500 (SFO-500) and 1000 ppm (SFO-1000). Results showed the highest efficiency of SFO-1000. The results obtained in this study demonstrated for the first time that Rosemary is a potent source of natural inhibitors of α-amylase and pancreatic lipase with powerful antioxidants proprieties that might be used in the food stabilization and the prevention of diabetes and obesity complications as a complementary pharmacological drug.

Study of the effect of chemical treatments on the tensile behaviour of abaca fiber reinforced polypropylene composites

Abstract: Abaca fibers were subjected to different chemical treatments like alkali treatment, permanganate treatment, acrylation & benzene diazonium chloride treatment and these chemically treated fibers were used as reinforcements in the preparation of polypropylene composites by hot compression moulding method. Various composites were fabricated with different fiber loadings of 20%, 30%, 40%, 50%, 60%, and 70%. Abaca composites with 40% fiber loadings were found to have optimum properties when tensile tests were carried out and the study also revealed that treated composites were found to have improved tensile properties when compared to untreated composites. Among all the treatments carried out benzene diazonium chloride treated abaca fiber reinforced polypropylene composites showed higher tensile strength. These composites showed 82.38% increase in tensile strength when compared to untreated composites for 40% fiber loading.

Activity and stability of immobilized Candida rugosa lipase on chitosan coated Fe3O4 nanoparticles in aqueous and organic media

Abstract: Fe 3 O 4 (magnetite) nanoparticles were prepared by coprecipitation method, coated by chitosan and functionalized by glutaraldehyde. Lipase enzyme from Candida rugosa was immobilized on the prepared particles via cross linking reaction. Synthesis steps and characterization were examined by XRD, TEM, and FTIR. The immobilization conditions were 10 mL of phosphate buffer (0.1 M, pH 6.5) containing 30 mg of functionalized magnetic chitosan nanoparticles and 2.0 mg·mL -1 of lipase, immobilization temperature of 4 ℃ and immobilization time of 1 h. Under these conditions, lipase was successfully immobilized with loading capacity of 87 mg/g. The immobilized enzyme showed good operational and storage stability, where it remained stable after 30 days of storage at 4◦C.and retained about 61% of its initial activity after twenty repeated uses. Finally enzymatic catalyze synthesis of butyl and hexyl oleate at 40 ◦C with shaking (200 rpm) was realized in n -hexane and confirmed by GC analysis.

The Analytical Applications And Biological Activity of Hydroxamic acids

Abstract: Hydroxamic acids play a vital role in applied chemistry , the present literature review is an investigation on the analytical applications and biological activity of hydroxamic acids . The review includes a survey of the historical background of hydroxamic acids , their general structure , classification , physical properties , stability and occurrence in nature . In addition the review discuss the synthesis and identification of hydroxamic acids ,in which different methods of synthesis and different analytical techniques for identification were outlined . The review also includes the wide use of hydroxamic acids , mainly their analytical applications and a summarized account of the biological activity of hydroxamic acids.

Using Microwave Irradiation for synthesis of Imides consist of Pyromellitimide

Abstract: Bispyromellitimides are an important class of substrates in polymer chemistry as monomers in polyimides or their copolymers synthesis.A fast and efficient microwave-assisted synthetic procedure for the preparation of series of these compounds 3(a-h) from the reaction of pyromellitic anhydride and aniline or its derivatives (a-h) is described. Elemental analysis, FT-IR and 1 H-FT-NMR Spectra revealed the confirmation of these compounds in good agreement.

Study of the influence of the shape and size of the ZnO nanoparticles synthesized from different precursors on the antibacterial activity

Abstract: Three different shapes of ZnO nanoparticles were synthesized using three different precursors. The synthesized samples have been characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). The XRD measurements reveal that the prepared nanomaterials have a hexagonal wurtzite structure. TEM observations showed that the form and the size of nanoparticles depend on the precursor used to prepare ZnO. The antibacterial activities of the different prepared ZnO nanoparticles were tested against Staphilococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria. The results obtained have shown that the antibacterial activities depend on the concentration, shape (agglomerates, hexagonal microrods and hexagonal nanoparticles) and crystallite size of ZnO particles. The minimum concentration of ZnO nanoparticles that inhibits the growth Staphilococcus aureus or Escherichia coli (0.015 mg/ml) is very lower than those reported by many authors indicating that the ZnO nanoparticles agglomerates act efficiently even at very low concentrations and with the same sensitivity against the two types of bacteria.

Effect of the Mg/Al ratio and of the rate of reinforcement on the synthesis of a nanocomposite Cellulose/Hydrotalcite.

Abstract: The objective of this work is to synthesize a nonmaterial by introducing synthetic clay (hydrotalcite) as a nanofiller in a natural polymer matrix (cellulose) and to study the effect of Mg/Al ratio and the rates of reinforcement. Cellulose fibers were extracted from ‘Yucca‘ tree’s leaves by a chemical treatment and Hydrotalcite (MgAlCO3) was synthesized by the method of co-precipitation at fixed pH with a ratio of Mg/Al=2 or 3. The composite materials were elaborated by microwave activation.The Hydrotalcites with an Mg/Al ratio = 2 or 3 were tested as well as various rates of reinforcement (2, 5 or 10% Hydrotalcite) in order to optimize conditions of obtaining a nanomaterial. The structures of obtained materials were characterized by IR spectroscopy, X-ray Diffraction and Transmission Electron Microscopy. The thermal stability was analyzed by TG-DTA analyses. The characterizations carried out on these compounds revealed structural modifications in agreement with the formation of a nanomaterial (cellulose/Hydrotalcite) with the improved thermal properties.

Recent Developments In Chemistry Of 1,3,4-Thiadiazoles

Abstract: The methods of preparation, structure and biological activities of 1,3,4-thiadiazoles are reported.

Electrospun Nanofibers of Acrylonitrile and Itaconic Acid Copolymers and their Stabilization

Abstract: (APS) as an oxidant in the aqueous medium,and nanofibers produced by electrospinning . Electrospun nanofiber mats were by treated heat under air atmosphere to be stabilized. Nanofiber production from AN-IA copolymers and suitability of the nanofiber as carbon nanofiber precursor is discussed. Copolymer are characterized using Fourier Transform Infrared Attenuated Total Reflectance spectrometer (FTIR-ATR), Nuclear Magnetic Resonance Spectroscopy ( 1 H-NMR), differential scanning calorimeter (DSC), thermal gravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The effect of IA content on the spectroscopic and thermal properties of AN-IA copolymers was investigated. Increasing IA content confirmed by spectroscopic methods seriously affects thermal properties which is important for carbon nanofiber production. IA provides a catalytic effect on stabilization process by decreasing initiation cyclization reaction temperature from 202 to 195 o C. Elecrospinning from the AN-IA copolymer solutions in dimethyl foramide (DMF) was performed, morphology of nanofibers was monitored using Scanning Electron Microscopy (SEM). Bead free nanofibers were produced from AN-IA copolymer solutions under same conditions. Average nanofiber diameter decreases from 878±18 to 376±7 nm according to increasing IA content in copolymers. The nanofiber mats produced were treated at high temperature under air atmosphere for oxidative stabilization. Stabilized nanofibers were characterized using FTIR-ATR spectrometer and a new structure was monitored as a result of cyclization reactions. The stabilized nanofibers were also characterized mophologically using SEM. Volume loss occurring after heat treatment calculated based on the nanofiber diameter changes. Consequently, electrospun nanofibers can be suggested as a carbon nanofiber precursor due to suitability for electrospinning and stabilization process.

Adsorption of U(VI) from aqueous solution by Triocthylamine (TOA) functionalized magnetite nanoparticles as a novel adsorbent

Abstract: Adsorption of U (VI) from aqueous solutions was investigated using magnetically assisted chemical separation (MACS) process. In the present study, Triocthylamine (TOA) functionalized magnetite nanoparticles (TOAFMNPs) were applied as a novel adsorbent for adsorption of U (VI) from aqueous solutions. The effects of initial pH, Triocthylamine to magnetite nanoparticles weight ratio, amount of adsorbent, stirring time and initial U(VI) concentration on U(VI) adsorption efficiency were investigated by batch experiments. The adsorption of U(VI) using this adsorbent was pH dependent, and the optimal pH was 5.5. In kinetics studies, the adsorption equilibrium can be reach within 20 min., and the experimental data were well fitted by the pseudo-second-order model. The highest value of U(VI) adsorption (93.8%) was achieved in optimum conditions. The Langmuir isotherm model correlates well with the U(VI) adsorption equilibrium data for the concentration range 10-80 mg/l. The maximum U(VI) adsorption capacity onto adsorbent was 27.5 mg/g at room temperature. Present study suggests that TOAFMNPs could be employed as a potential adsorbent for U(VI) adsorption, and also could provide a simple and fast separation method for removal of U(VI) ion from solutions

SYNTHESIS AND REACTIONS OF SOME NEW MORPHOLINYLPYRROLYL TETRAHYDROTHIENO[2,3-c] ISOQUINOLINE

Abstract: Hydrazinolysis of ethyl-5-morpholin-4-yl-1-(1H-pyrrol-1-yl)-6,7,8,9-tetrahydrothieno[2,3-c]iso- quinoline-2-carboxylate afforded the corresponding carbo- hydrazide which upon condensation with aromatic aldehydes, acetyl acetone and/ or carbon disulfide gave N- arylidinecarbohydrazide, dimethylpyrazolyl methanone, [1,3,4]oxadiazole-2-thiol and its ethyl ester derivatives respectively. Diazotization of the carbohydrazide with nitrous acid afforded the corresponding carboazide which was used for synthesis of carbamates and substituted carboxamides. Boiling of the carboazide in dry xylene afforded the pyrazinone compound which was used for synthesis of other heterocycles containing pyrrolopyrazinothinoisoquinoline moeity.

Crystal Growth and Characterization of the Non-Centrosymmetric Hydrated Co-hexaborate templated by racemic 2-methylpiperazinium (C5H14N2){Co[B6O7(OH)6]2}.2H2O

Abstract: Large single crystals of the non-centrosymmetric hydrated Co-hexaborate (C5H14N2){Co[B6O7(OH)6]2}.2H2O were grown from aqueous solution and characterized by powder and single-crystal XRD methods, IR, UV-Vis and photoluminescence spectroscopy measurements. Single-crystal XRD analyses show that the reported compound crystallizes in the orthorhombic non-centrosymmetric space group Fdd2 and its crystal structure consists of anionic molecular Co-hexaborate units arranged into 3D-supramolecular honey-comb like structure network with the organic cation and water of crystallization occupying large tunnels voids along [110] through strong hydrogen bond interactions. In addition, Its electronic properties have also been investigated showing a considerable important gap energy well proving the semiconductor behavior and the photoluminescent property of reported material.

Synthesis, spectral characterization, cyclic voltammety, molecular modeling and catalytic activity of sulfa-drug divalent metal complexes

Abstract: Complexes of cobalt(II), nickel(II), copper(II), zinc(II) and Hafnium(II) of general composition [M(L) 2 (Cl) 2 ] have been synthesized [L = 4-(phenylphosphinylideneamino-N-thiazolylbenzenesulfonamide]. The elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, IR, UV, NMR, SEM, EDX, thermal and EPR spectral studies of the compounds led to the conclusion that the ligand acts as a bidentate manner. The molar conductance of the complexes in fresh solution of DMSO lies in the range of 7.46–9.13 Ω -1 cm 2 mol ‒1 indicating their non-electrolytic behavior. On the basis of analytical and spectroscopic techniques, octahedral geometry of the complexes was proposed. The ligand acts as bidentate ligand, coordinated through sulfonamide oxygen and thiazole nitrogen atoms. The ligand field parameters were calculated for Co(II), Ni(II) and Cu(II) complexes and their values were found in the range reported for a octahedral structure. The catalytic activities of the divalent metal complexes have been studied in the oxidation of cyclohexane, using environmental friendly oxidant, hydrogen peroxide. Complex with rough surface has shown higher catalytic activity compared to the other complexes. The molecular parameters of the ligand and its Co(II) and Hf(II) complexes have been calculated.

Quantification of residual clove oil, benzocaine and tricaine in fish fillets using SPE and UPLC-DAD

Abstract: Residual quantification of the anesthetics clove oil (CO) – isoeugenol (ISO), eugenol (EUG) and methyleugenol (MET) –, benzocaine (BZN) and tricaine (MS-222) was made in fillets of two fish species: Nile tilapia (Oreochromis niloticus) and a catfish hybrid, cachadia (Pseudoplatystoma reticulatum x Leiarius marmoratus). Samples (n=4) of each fish were evaluated after submitted to anesthesia in five dosages defined based on the induction time of each species after depuration times (0h, 12h, 24h and 48h). Different methodologies of sample preparation were tested and selected according to the better recovery. The quantification of anesthetics was performed by UPLC-DAD. The variance of residual means among anesthetics, dosages and fish species was compared. After anesthesia (0h) both species, tilapia and cachadia, presented residual anesthetics. Fishes depurated during 12h, 24h and 48h did not present detectable values, it means, values were below the limits of detection. BZN presented the highest mean residual concentration for tilapia and cachadia (p=0.01), while MS-222 presented the lowest residual amounts in tilapias and EUG in cachadias, what may be related to the metabolism and carcass composition of each fish species. There were no significant differences among the five dosages, except the lowest MS-222 concentration in tilapias that resulted in higher residual concentrations because low dosages increase the induction time and consequently the permanence of the fish in anesthesia. Ultimately, mean values of residues in cachadia were higher than in tilapia, and MS-222 and EUG presented the lowest residual values for tilapia and cachadia, respectively.

SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL ACTIVITY OF NOVEL PYRAZOLO[3,4-b]PYRIDINES AND THEIR SPIRO-HETEROCYCLIC DERIVATIVES

Abstract: The present work describes the synthesis of a novel series of heterocyclic moieties derived from 5-acetylpyrazolo[3,4-b]pyridine (1). The formation of chalcones (2a-d) was utilized to synthesize pyrazoline, isoxazoline and pyrimidine derivatives (3-10). Thiosemicarbazone and semicarbazone (11, 17) were utilized to synthesize other new triazolethiones, thiadiazole and selenadiazole derivatives (11-19). Some new spiro derivatives (22-25) were synthesized by the reaction of chalcone (21) of 1 and isatine with hydrazines, hydroxyl amines and thiourea. Also, The reaction of 1 with cyanoacetyl hydrazine gave the hydrazide-hydrazone derivative 26, which was allowed to react with aromatic aldehydes and α-cyanocinnamonitrile to afford coumarine and substituted pyridine derivatives (28, 29). The structures of all the new compounds have been established on the basis of their analytical and spectral data. Twenty two of the synthesized compounds were also evaluated for their antibacterial and antifungal activity against various strains of bacteria and fungi and most are found to possess promising antimicrobial activity when compared with Chloramphenicol and Clotrimazole.

Regioselective and facile oxidative thiocyanation of anilines and indoles with trans-3,5‐dihydroperoxy‐3,5‐dimethyl‐1,2‐dioxolane

Abstract: Oxidative potential of trans ‐3,5‐dihydroperoxy‐3,5‐dimethyl‐1,2‐dioxolane (DHPODMDO) has been explored in the facile thiocyanation of anilines and indoles through the efficient and in situ generation of SCN + ion from sodium thiocyanate. The reactions proceed with regioselectivity under mild conditions at room temperature to afford the respective thiocyanate derivatives in excellent yields and low reaction times.

Bentonite/Chitosan Biocomposite as an Adsorbent for Hexavalent Chromium From Aqueous Solutions

Abstract: The present work focuses on the study of the application of abundant and less expensive materials such as chitosan and bentonite/chitosan biocomposite in the removal of hexavalent chromium. Spectroscopic analysis like techniques FTIR, XRD and BET have been used to characterize the adsorbents. The data indicate that the adsorption of chromium proceeds kinetically according to a pseudo-second order model on both samples and the apparent activation energy (Ea) have been measured to be 22.9 kJ.mol −1 and 84.4 kJ.mol −1 for chitosan and 5%Bt/CS, respectively. The adsorption isotherm experiments show that the adsorption capacity depends on the studied chromium adsorption temperature. It has been found that the data could be well described by the Langmuir as well as the Freundlich models. Thermodynamic parameters (i.e., change in the free energy (DG°), the enthalpy (DH°), and the entropy (DS°) have been also, evaluated.

Extraction-Spectrophotometric Studies on the Complex Formation of Iron(III) with 4-(2-Thiazolylazo)Resorcinol and Tetrazolium Salts

Abstract: Four liquid-liquid extraction-chromogenic systems containing Fe(III), 4-(2-thiazolylazo)resorcinol (TAR), tetrazolium salt (TZS), water and chloroform were studied. 2,3,5-Triphenyl-2H-tetrazolium chloride (TTC), 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H-tetrazolium bromide (MTT), 3-(2-naphtyl)-2,5-diphenyl-2H-tetrazolium chloride (TV), and 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (INT) were the examined TZSs. Optimization experiments for iron extraction were performed and the following parameters were found for each system: pH(opt), C TAR (opt), C TZS (opt), shaking time (opt), and l(opt). Under the optimum conditions, the molar ratio of the reacting Fe(III), TAR and TZS is 1:2:2 and the general formula of the extracted species is (TZ + ) 2 [Fe II (TAR 2– ) 2 ]. Some equilibrium constants (constants of association, constants of distribution, and constants of extraction) and analytical characteristics (molar absorptivities, Sandell’s sensitivities, Beer’s law limits, etc.) were calculated. Linear relationships involving the molecular mass of TZ + were discussed.

Synthesis, Characterization and Application of Nano-adsorbent Materials in the Sorption of Pb(II), Ni(II), Co(II), Mn(II), Li(I) from Aqueous Solution

Abstract: In this study, nano-adsorbent materials were synthesized from two different precursors by thermal activation technique. The first was the synthesizing of nano-zinc silicate from chemical reagents of zinc oxide and commercial silica gel. The second was the preparation of nano-pore size activated carbon from different biomass. The synthesized nano-adsorbent materials were characterized by different techniques; Surface Area, FTIR, XRD and SEM. The prepared nano-adsorbent materials were applied in the sorption and separation of some heavy metals from aqueous solution. These metals includes; Pb (II), Ni(II), Co(II), Mn(II) and Li(I). Some factors affecting on the sorption process (e.g. contact time and pH) were investigated. It was found that: the nano-zinc silicate (of ratio 1:1 thermally treated at 700 0 C) and nano-pores activated carbon (prepared from saw dust impregnated with 70% H 3 PO 4 overnight, then heated to 500 0 C in presence of steam for 80 min.) were the best samples for sorption and separation of concerned heavy metals.

Green synthesis of Novel Schiff bases derived from 2, 6 diamino pyridine – Characterization and Biological activity

Abstract: Present work produces an excellent green route for the synthesis of Schiff bases derived from 2, 6 diamino pyridine, by using lemon juice as the catalyst. This method is experimentally simple, quick, clean and high yielding. Purity and yield of the reaction is increased by using lemon juice there by avoided the traditional dehydrating agents like glacial acetic acid. This method was successfully extended for the synthesis of different Schiff bases derived from 2,6 diamino pyridine like N,N´-bis(2-hydroxy-1-napthalene)-2,6-pyridiamine, N,N´-bis(2-methoxy-1-napthalene)-2,6-pyridiamine and N,N´-bis (naphthalene)- 2,6-pyridiamine. These compounds were prepared by using catalytic amount of lemon juice, and found more economical, safe, neat and eco friendly than using other commercially available dehydrating agents. The synthesized compounds were characterized by FT-IR, 1HNMR spectroscopy, CHN analysis and mass. Compounds are screened for their antifungal activity against Aspergillusniger and M.fufur while antibacterial activity was checked against E.coli, Klebsiella, Bacillus cereus and Staphylococcus aureus. Hydroxyl derivative of the compound was showing significant anti bacterial activity against all selected bacteria. Klebsiella was showing a considerable inhibition compared to standard Tetracycline.

Synthesis of chalcones via claisen–schmidt condensation reaction catalyzed by silica-h2so4 under ultrasound irradiation

Abstract: The synthesis of 1,3-diaryl-2-propenones was carried out by using ultrasonic irradiation in the presence of silica-H 2 SO 4 , which was used as a catalyst in solvent-free conditions. The advantages of this process are the high yields (82–98%) it produces, the cost effectiveness of the catalyst, and the simple work-up and purification of products achieved via a non-chromatographic method.

Toxicological Impacts of Gas flaring and Other Petroleum Production Activities in Niger-Delta Environment

Abstract: In this study, the concentrations of inducers of environmental toxicity such as heavy metals and polycyclic aromatic hydrocarbon and biomarkers of environmental toxicants such as oxidative stress enzymes/compounds and liver function enzymes were determined. These parameters were used to assess the pollution status of some Niger-Delta areas; Ebocha/Omoku, Abacheke/Egbema, and Okwuzi/Ohaji, with the aid of two indicator species: cat fish (Ictalurus punctatus) and snakehead fish (Channa argus) from three different water sources; Ebocha/Omoku river, Abacheke river and Okwuzi creek all of which are within the area of oil exploration and production activities in Nigeria. The control fish and water samples were collected from Otamiri River within the Federal University of Technology, Owerri, Nigeria, with no known oil exploration and production activity. The results obtained indicated significant (p < 0.05) differences between the exploited and the unexploited environment and the need to incorporate biochemical markers in environmental impact assessment of aquatic environments to complements the classical chemical monitoring.

Organic Amino Acids Chelates; Preparation, Spectroscopic Characterization and Applications as Foliar Fertilizers

Abstract: Cu(II) complexes of amino acid hydrolyzate soya protein isolate have been prepared. In order to study the mode of coordination in the above chelates and their effect as foliar fertilizer, Mn(II), Co(II), Nil(II), Cu(II), Zn(II) and Cd(II) complexes of L-mino acids have been prepared and characterized by elemental and spectral analyses,( IR, UV-VIS, mass spectra and ESR), electrical conductance, magnetic moments and thermal analyses (DTA and TGA). ESR spectra of copper (II) complexes show isotropic and anisotropic types d(x 2 -y 2 ) with covalent bond character. The amino acids chelates were evaluated as foliar fertilizer by treating plants with micronutrient, amino acid solutions and varying concentrations of micronutrient amino acids chelats. It was found that spraying plant with 2.5% micronutrient amino acids chelats gives the best results regarding: plant height, stem diameter, leaves area, number of flowers, number of branches per plants and total yield per plant.

Heavy Metals Concentrations in the Shell and Tissue of Periwinkle (Tympanotonus fuscatus) and Giant Land Snail (Achatina fulica) in Soku Community of Niger Delta, Nigeria.

Abstract: The pollution of aquatic ecosystem by heavy metals has assumed serious proportions due to their toxicity and accumulative behaviour River dams are especially at risk of contamination by different contaminants from anthropogenic sources including heavy metals since change of sediment regime often occur The accumulation of five heavy metals; chromium (Cr), Cadmium (Cd), Lead (Pb), Copper (Cu) and Arsenic (As) in periwinkle, ( Tympanotonus fuscatus, var, radula ) and giant land snail ( Achatina fulica ) shell and soft tissue collected from Soku Community, Akuku-toru Local Government Area of Rivers State, Nigeria The periwinkle and giant land snail were processed and analyzed for heavy metals presence Results obtained showed that the periwinkles accumulated more of these heavy metals than the snails Copper and arsenic were the highest concentrated heavy metals in the periwinkle shell soft tissue The concentration of copper and arsenic in periwinkles soft tissue was found to be l,612 mg/kg and 240 mg/kg respectively In the giant land snail the soft tissue concentrated more of copper (277 mg/kg) These values exceeded set standards for guidelines on toxicity

Crystal Structure, Charge-Distribution and Bond-Valence-Sum Investigations of a Novel Arsenate Na3.5Cr1.83(AsO4)3

Abstract: The new compound Na 3.5 Cr 1.83 (AsO 4 ) 3 were synthesized by the flux method and characterized by single crystal X-ray diffraction. It crystallized in rhombohedral space group R -3c. The hexagonal unit-cell parameters were determined to be a h = 13.593 (4) A; c h = 18.605 (10) A; V = 2977 (2) A 3 and Z = 12. The title compound framework is built up from Cr 4 O 18 clusters and AsO 4 tetrahedron linked by corners. This arrangement leads to a three-dimensional anionic framework with interconnected cavities where the Na+ cations are located. This structure is closely related to that of II-Na 3 Fe 2 (AsO 4 ) 3 and differs from it by the partially occupied sites of Cr III , associated with an increase in sodium content for charge compensation. The structural formula can be written as Na 3.5 Cr 1.83 □ 0.17 (AsO 4 ) 3 . The structural model is validated by both bond-valence-sum and charge-distribution methods, and the distortion of the coordination polyhedra is analyzed by means of the effective coordination number. Sodium conduction properties are simulated by means of the bond-valence-sum (BVS) model.