Classical chemical sciences
3-Formylisocoumarin condensed with aromatic primary amines to give Schiff bases (2a-2d). These Schiff bases are then reacted with acid chlorides in the presence of base in toluene to give 1,3,4-substituted 2-azetidinones.
Keywords: 3-Formylisocoumarin, aromatic amines, acid chlorides, tri-n-butylamine, 2-azetidinones
The inhibition of the corrosion of carbon steel in sea water by diethylene triamine pentamethylene phosphonic acid (DTPMP) and Ni2+ has been investigated using weight loss and electrochemical measurements. The results show that 70% inhibition efficiency is achieved with binary system consisting of 250 ppm of DTPMP and 50 ppm of Ni2+.Polarization curves indicate that the system functioned as a cathodic inhibitor. AC impedance spectra reveal that a protective film is formed on the metal surface. The protective film has been analysed by FTIR spectra. The surface morphology and the roughness of the metal surface have been analysed by atomic force microscopy.
Keywords: corrosion inhibition; carbon steel; electrochemical techniques; atomic force microscopy; diethylenetriamine pentamethylenephosphonic acid
Densities and viscosities of binary mixtures of hexyl acetate with chlorobenzene, bromobenzene, fluorobenzene and nitrobenzene have been measured at (298.15, 303.15, 308.15 and 313.15) K over the entire composition range. Speeds of sound of these binary liquid mixtures have also been measured at 303.15 K. From the experimental density and viscosity data, the values of excess molar volume VE , free energy of activation for viscous flow ΔGE, while from the speed of sound data the isentropic compressibility KS, intermolecular free length Lf, internal pressure πi, free volume Vf, and specific acoustic impedance Z have been calculated. The excess molar volumes for these binary mixtures were negative over the whole composition range at all temperatures. The viscosity values were correlated using Frenkel and McAllister (four-body) models.
Keywords: density, viscosity, excess molar volume, speed of sound, hexyl acetate; halobenzenes; nitrobenzene
A simple and satisfactory environment friendly procedure for synthesis of some antimicrobial azo-Schiff bases is presented. The condensation of o-hydroxy azoaldehydes and diaminomaleonitrile in the presence of a catalytic amount of acetic acid produced desired Schiff bases in high yields.
Keywords: Schiff base, azo dye, diaminomaleonitrile, salicylaldehyde, antimicrobial, o-hydroxy azoaldehydes
The present work deals with the reaction of 4-(4-acetylaminophenyl-4-oxobut-2-enoic acid (1) with sulfur reagents, e.g. thiophenol at different acidity of medium, phenol in the presence of concd. sulfuric acid, and phosphorous pentachloride to afford the corresponding adducts 2-6. Reaction of the latter compounds with different electrophilic and nucleophilic reagents yields some important heterocyclic derivatives.
Keywords: (E)-4-aryl-4-oxo-2-butenoic acid, thiophenone, furanone, benzofuranone, thiadiazole, pyridazinone, 1,2-oxazolone, benzoxazinone, quinazolinone, pyrrole, pyrazole, 1,2,4-triazine
A series of new thiourea derivatives containing quinazoline-4(3H)-one framework (3a-d) was successfully synthesized and characterized by IR, 1H NMR, 13C NMR spectroscopy, ESI mass spectrometry and elemental analysis. Variation in the functional group at the phenyl ring led to set of compounds bearing quinazoline-4(3H)-one accommodated substituted phenyl thioureas.
Keywords: Heterocyclic thiourea derivatives, quinazolin-4(3H)-one moiety, phenyl isothiocyanates
An aqueous extract of Aloe vera (L) Burm f. (Liliaceae) has been used as a corrosion inhibitor in controlling corrosion of carbon steel immersed in sea water. Weight loss method reveals that 4ml of the extract provide 98% inhibition efficiency. The protective film has been analyzed using Fourier transform infrared (FTIR) spectroscopy and fluorescence spectroscopy. Electrochemical studies such as potentiodynamic polarization and alternating current impedance spectra have been used to find the mechanistic aspects of corrosion inhibition.
Keywords: carbon steel, corrosion inhibition, plant extract, aleovera, seawater, green inhibitor
A simple and efficient protocol has been reported for the synthesis of 5-ethoxycarbonyl-6-methyl-4-aryl-3,4-dihydropyrimidin-2(1H)- ones using nanoparticulate ferrite composite as recyclable catalyst for one pot three component Biginelli reaction to afford the corresponding product in excellent yields.
Keywords: 3, 4-Dihydropyrimidin-2(1H)-ones, Ferrite composite, Multicomponent reaction
Spectrophotometric studies were carried out to investigate the charge-transfer reaction between cinnarizine and dipicrylamine (DPA) or 2,6-dinitrophenol (DNP). Simple and rapid spectrophotometric methods were suggested for the determination of cinnarizine (CN) in pure and in its pharmaceutical dosage forms. The colored products are quantified spectrophotometrically at 430 and 440 nm for cinnarizine complexes with DPA in a mixture of 15% dioxane in dichloroethane (I) and 15% ethyl acetate in chloroform (II), respectively. On the other hand, cinnarizine complexes formed with DNP in acetonitrile (III) and in a mixture of 30% dichloroethane in ethyl alcohol (IV) were quantified at 460 and 430 nm, respectively. The proposed procedures were successfully utilized for the determination of the drug in its pharmaceutical formulation using standard addition and calibration curve methods. Beer's law was obeyed in the concentration ranges 1.00- 22.00, 1.50-36.80, 1.50-36.80 and 3.60-36.80 μg mL-1 cinnarizine with molar absorpitivities of 1.64×104, 1.43×104, 5.16×104 and 3.60×104 (L mol-1 cm-1), for CN-DPA in mixture (I), CN-DPA in mixture (II), CN-DNP in acetonitrile (III) and CN-DNP in mixture (IV), respectively. The relative standard deviations are less than 1.02%. The results of analysis of commercial tablets (Cinnarizine-25) showed that there is no interference from any excipient. Statistical comparison of the results was performed with regard to accuracy and precision using student's t-test and F-ratio at 95% confidence level.
Keywords: Spectrophotometric determination, Cinnarizine, Charge-transfer complexes, Polynitrobenzene π-acceptors
Materials and environmental chemistry
The copper(II) complex of N-[ethyl(butyl)carbamothioyl]-3,5-dinitrobenzamide (1) has been synthesized and characterized by elemental analysis, IR spectroscopy and atmospheric pressure chemical ionization-mass spectrometry (MS-APCI). Thermogravimetric analysis shows the complex (2) decomposes in two-step to form copper sulfide. The complex was used as single-source precursor for the deposition of copper sulfide thin film by aerosol assisted chemical vapour deposition (AA-CVD) at 350 oC. Powder X-ray diffraction (p-XRD) pattern of thin film of complex showed the deposition of monoclinic roxbyite Cu7S4 and orthorhombic anilite Cu7S4 phases at 350 oC with spherical crystallites. The degree of film surface roughness was determined by atomic force microscopy (AFM). The scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) results showed the uniform distribution of copper sulfide in the film, which makes it useful semiconducting material on a structured surface.
Keywords: Copper complex; copper sulphide (Cu7S4); thin film; aerosol assisted chemical vapour deposition (AA-CVD); SEM; powder XRD; N-[ethyl(butyl)carbamothioyl]-3,5-dinitrobenzamide ligand
Variations in mineral element and heavy metal contents of some edible herbs grown on crude oil post remediated agricultural soil was carried out after four weeks of growth on the bioaugmented and natural attenuated soils. The result showed a slight decrease in all the mineral elements analyzed. However, Potassium had the highest concentration 5.5020+0.1056 % and 4.7007+0.6510 % for Tallinium triangulare and Amarantus hybridus planted on the bioaugmented site. Heavy metals concentration increased in all the vegetables after 4 weeks of growth with highest values of 0.0803+0.0006 %, 0.0813+0.0012 % and 0.8170+0.0015 % for Telfeiria occidentalis, Tallinium triangulare, and Amarantus hybridus planted on the natural attenuated site respectively.
Keywords: Bioaccumulation; mineral elements; heavy metals, vegetables; soil
The present study deals with the feasibility of removal of basic dye Rhodamine-B (RB) from aqueous solutions by using a low cost natural adsorbent lignin. Batch adsorption studies were conducted to evaluate various experimental parameters such as, contact time, initial concentration of the adsorbate, adsorbent dosage, pH and temperature. Pseudo first order and pseudo second order were used to fit the experimental data. Pseudo second order kinetics described of adsorption reasonably well. The experimental isotherms data were also modelled by the Langmuir and Freundlich equation of adsorption. Equilibrium data fitted well with the Freundlich isotherm. Lignin was shown to be a promising material for adsorption of RB from aqueous solutions.
Keywords: kinetics, adsorption, Lignin, Rhodamine-B, dye
This investigation studies the adsorption of Pt2+ and Au3+ ions from nitrate solutions using nanoparticles of magnetite (Fe3O4) synthesized in this work. The study is carried out by the analysis of the adsorption of Pt2+ and Au3+ ions on the surface of the nanoparticles by modifying several variables: contact time, solution pH, and initial Pt2+ and Au3+ ion concentration. The highly crystalline nature of the magnetite structure with a diameter of around 10 nm was characterized with transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The surface area was determined to be 117.5 m2·g–1. The surface functional groups were investigated with Fourier transforminfrared spectroscopy (FTIR) as well. Batch experiments were carried out to determine the adsorption kinetics and mechanism of Pt2+ and Au3+ by these magnetite nanoparticles. The adsorption process was found to be pH dependent. The adsorption process better followed the pseudo-second-order equation and Freundlich isotherm. It has been found that the equilibrium can be attained in less than 5 min. Immersion microcalorimetry was explored as a new tool to establish the adsorption capacity of the ions under study with promising results.
Keywords: adsorption, Langmuir, Freundlich, magnetite, heavy metals, immersion calorimetry.
The tannery effluent collected at monthly interval from January 2011 to December 2011 and analyzed for its characteristics. Samples were collected from one of the tannery from Jajmau area of Kanpur city of India. Results of the analysis showed that presence of addition chemical load like iron, calcium, magnesium, carbonate, bicarbonate, chloride and BOD were found in the discharged effluent of the above stated tannery. The analysis of various physical and chemical characteristics of tannery effluents showed variations according to month and results reveals that these are certain relationships between physico-chemical characteristics of effluents both positive and negative.
Keywords: tannery, pollution, BOD, industry, potassium permanganate (KMnO4)
Modified unsaturated polyester (MUPE) was blended with Cellulose (Cls) and with ethyl cellulose (ECls) at ambient conditions in the presence of ethyl methyl ketone peroxide (EMKP) as hardener. The blends containing different weight percentages (5-25 %) of Cls or ECls. Mechanical properties (impact strength, hardness, and bending) and dielectric constant were determined. The results observed that Cls increases the impact strength, hardness, and dielectric constant and decreases the bending of the MUPS, while ECls causes an increase in the three mechanical behaviours and a decrease in the dielectric constant of the MU-PS.
Keywords: unsaturated polyester, resins, mechanical, dielectric constant; cellulose and ethyl cellulose blends
It has long been known that the absorption of terrestrial energy by water molecules is the largest one (60-75 %), comparing with the lower value (20-24 %) of carbon dioxide molecules. The other gases with greenhouse effect absorb this energy in much smaller extent (8-12 %). In the last 360 years, considering from the industrial revolution, the amount of water vapor resulting on the basis of eight types of major processes, by direct and indirect human activities, and getting into the atmosphere was continuously growing. These are determined, by the appearance of very numerous human activities originated water-vapor/steam generators, the continuous increase of the greenhouse effect and the climate change. The following levels of special and extraordinary behavior of the atmospheric water vapor can be distinguished: 1) molecular, 2) associative (cluster) level, 3) condensation level which can be joined to phase transformations - mainly in the clouds, 4) the level of precipitate formation followed by intense moisture transport, 5) the level of firm difference existing between the atmospheric relations of the Northern and the Southern Hemisphere, mainly due to human activities. The atmosphere near the Earth's surface (in the troposphere) has such a well delimited temperature and pressure domain, in which water with its unique property occurs in all three phases. Water vapors condense easily. The triple point of the other atmospheric components is not achieved. This unique and extraordinary feature of the water plays a determining role in the meteorological processes of the Earth and the development of the climatic relations. All this warming, among other things, is manifested in the melting of the ice of the North Pole and the elevation of the snow altitude line. The primary task is the stopping of the warming of the North Pole Region and the promotion of its cooling. Global solutions appear as mandatory needs, which are very costly to start because extensive investments are required.
Keywords: global warming, greenhouse effect, atmospheric water vapor (AWV), greenhouse gases, carbon-dioxide, human activities originated water vapor generators, absorption of long wave radiation, precipitate formation and transport
the absence and presence of Zn2+has been evaluated by weight loss method. The formulation consisting of 250 ppm CMC and 50 ppm Zn2+ has 98 % IE. A synergistic effect exists between CMC and Zn2+. Synergism has been confirmed by synergism parameter. AC impedance spectra confirm the formation of protective film on the metal surface. The nature of the protective film has been characterized by scanning electron microscopy (SEM).
Keywords: Carboxymethyl cellulose, carbon steel, ground water, SEM, AFM, F-Test, corrosion inhibition
In this paper, application of sawdust prepared from Narra wood (SD) modified with cationic surfactant of cetyltrimethylammonium bromide (SD/CTAB) was used for removal of two typical acid dyes commercially named as Acid Green 25 (AG25) and Acid Red 14 (AR14) from aqueous solutions. The effects of experimental variables, such as pH, initial dye concentration, adsorbent dose, contact time and temperature were investigated in order to find out the optimized conditions for removal of selected test dyes. Langmuir and Freundlich Isotherms were used to analyse the experimental adsorption data. Pseudo- first and second order models suggested by Lagergren, Ho and McKay were used for kinetic study. The van 't Hoff equation employed for obtaining of thermodynamic parameters. It was found that upon simple treatment of sawdust with a cationic surfactant, the adsorption capacity of sawdust for uptake of anionic dyes is improved considerably. The monolayer maximum adsorption capacity of SD/CTAB toward AG25 and AR14 dyes calculated using Langmuir isotherm model was 17.5 and 18.9 mg g−1 at 298 K, respectively. Based on kinetics and thermodynamic studies, it was found that adsorption process using SD/CTAB follows pseudo second-order rate equation and the adsorption investigated system is spontaneous and endothermic in nature. Exhausted adsorbent can also be regenerated for reuse with high performance. It was found that via simple treatment of agricultural wastes such as wood sawdust with cationic surfactants it is possible to improve the sorption capacity of sawdust for removal of anionic dyes from aqueous wastes considerably.
Keywords: Removal, acidic dyes, modified sawdust, cationic surfactant, isotherm, kinetic, thermodynamic
Biochemistry, molecular biology and biotechnology
Variations in nutritional potentials of some edible vegetables grown on crude oil post remediated agricultural soil was carried out after four weeks of growth on the bioaugmented and natural attenuated soils. The result showed variations in both the vitamin content and proximate composition of the vegetables. Telfairia occidentalis grown on bioaugmented site had the highest concentration of vitamins B2, B3 and E with an increase of 16.5425 % for vitamin B2 and decrease of 7.8747 % and 6.6143 % for vitamins B3 and E, while Tallinium triangulare grown on natural attenuated site had the highest concentration of vitamins A, B1, B2, B3, B6, C and E with decrease of 12.7558 %, 5.3239 %, 6.2900 %, 2.4000 %, 2.8834 %, 0.1508 %, and 21.4117 %. Moreover Amarantus hybridus grown on the natural attenuated site had the highest increase in vitamins A, B1, B6, C and E with decrease of 5.4216 %, 16.2200 %, 4.7159 %, 1.7580 % and 3.5965 %. Proximate composition of the vegetables showed that Telfairia occidentalis grown on bioaugmented site had the highest concentration of lipid, carbohydrate, moisture, and crude fibre with increase of 125.1487 %, 3.0111 %, 3.0600 % and 6.2500 % respectively, while Tallinium triangulare grown on bioaugmented site had the highest concentrations of lipid, carbohydrate and ash with increase of 430.0000 %, 27.7592 % and 31.2846 % respectively. However, Amarantus hybridus also grown on bioaugmented site had the highest concentrations of lipid, carbohydrate and moisture with increase of 349.9631%, and 1.4593% for lipid and moisture, while carbohydrate had a decrease of 12.4762% when compared to their respective controls.
Keywords: Bioremediation, Proximate composition, Vitamins, vegetables
Industrial and engineering chemistry
The gray model and the genetic algorithm for predicting natural gas yield have been introduced in the present article. Two new methods for forecasting the yield of natural gas in China have also been pointed out based on the gray model and the genetic algorithm. The experimental results show that both models can predict the yield of natural gas and the experimental data are in agreement with the quantitative analytical conclusions drawn from the calculated data. This proves that two types of new models can be used to predict the yield of natural gas. It results in good economic and social benefits in China.
Keywords: prediction, natural gas, China, gray model, genetic algorithm