European Journal of Chemistry

A method is presented to enable the preparation of superhydrophobic polymer/tungsten (VI) oxide (WO₃) nanocomposite coatings on glass substrates. WO₃ nanoparticles were incorporated via the swell-encapsulation-shrink method into superhydrophobic silicone polymer films deposited on glass via aerosol-assisted chemical vapour deposition (AACVD) to produce the novel nanocomposite films. The technique overcomes the limitations of previous methods for nanoparticle incorporation to provide a synthetic route to previously unattainable materials. The nanocomposite films retain the properties of the superhydrophobic polymer while the presence of the nanoparticles is clearly evident. As such, the films have a range of potential applications including high surface area photocatalysis and self-cleaning photochromic or electrochromic coatings. The two-stage synthesis is shown to be flexible and suggests great scope for producing any number of future novel materials. The thin films were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, X-ray photoelectron spectroscopy (XPS), infra-red (FTIR) spectroscopy, X-ray diffractometry (XRD) and water droplet contact angle measurements.

A number of reactive azo dyes based on chromene moiety were prepared through two inversed routes using 2-amino-7-hydroxy-4-phenyl-4H-chromene-3-carbonitrile, which when coupled to different diazonium salts, yielded the corresponding dyes which were then further reacted with cyanuric chloride. The structures of the prepared dyes were elucidated from their spectral data, elemental analyses and colour measurements. Dyeing of cellulosic and nylon fibers using the prepared dyes was done under suitable conditions. Some properties of the prepared dyes such as fastness properties (washing, rubbing and perspiration) and colour measurements were investigated. The dyes showed very good fastness to washing properties when attached to nylon fibers but poor fastness to light properties were shown.

A new series of aryl clonazepam derivatives (11-16) have been synthesized by employing Suzuki Cross-coupling reaction, which includes the reaction of clonazepam with suitable derivative boronic acid at the presence of Pd(PPh₃)₄ as catalyst, and Na₂CO₃ as a base. The structures of the newly synthesized compounds were assigned by ¹H, ¹³C and 2D NMR spectroscopic techniques.

A simple, rapid, and sensitive spectroflourimetric method was developed for the determination of menbutone. The method is based on measuring the native fluorescence of the alkaline aqueous methanolic solution of the cited drug at its optimum excitation and emission wavelengths at λ_em 378 nm, upon excitation at λ_ex 300 nm. The method showed good linearity over the range of 0.2-2.0 µg/mL with a detection and quantitation limits of 7.25 and 24.15 ng/mL, respectively. The suggested method was successfully applied to the analysis of menbutone in its commercial veterinary formulations and the results obtained were in good agreement with those given with the manufacturer method. The method was further extended to the determination of menbutone residues in bovine meat and milk, and the results were satisfactory. The recoveries obtained were in the 98.50-102.25% range. No organic solvents were used in the extraction procedures, therefore, the proposed method can be considered as a type of 'green' chemical process.

Four simple and specific spectrophotometric methods were developed and validated for the simultaneous determination of binary mixture of ibuprofen and famotidine, using unified regression equation. The proposed spectrophotometric procedures including, derivative ratio, ratio subtraction, dual wavelength and mean centering of ratio spectra do not require any separation steps. Accuracy, precision and linearity ranges of the proposed methods were determined and the specificity was assessed by analysing synthetic mixtures of both drugs. The methods were applied to a pharmaceutical formulation and the results obtained showed that there is no significant difference between the proposed methods and the reported one regarding both accuracy and precision.

The reaction paths of the C-C and C-H bond cleavage in the anthracene and phenanthrene aromatic molecules are studied by applying the ab-initio DFT method. It is found that the C-C bond cleavage proceeds via a singlet aromatic transition state, compelled through a disrotatoric ring opening reaction. A suprafacial H atom shift follows the transition state, leading to the formation of a methylene -CH₂ and an acetylenic or allenic moiety. The calculated activation energies for anthracene range from 158.81-208.90 kcal/mol and the reaction energies from 96.106-156.976 kcal/mol. For phenanthrene, the energy values are 157.39-202.34 kcal/mol and 62.639-182.423 kcal/mol, respectively. For the C-H cleavage reactions, the calculated reaction energies for all C-H bonds in both molecules are almost similar, 116-117 kcal/mol. The activation energy values for anthracene and phenanthreneare 149.75-161.27 and 161.24-163.00 kcal/mol, respectively.

Carbon dioxide is the major content of greenhouse gases, which is released by many industries such as paper, cement and steel industries etc. Removal or separation of CO₂ from the atmosphere is a challenging task for the researchers as it related to the human health and affects environment. Many methods and techniques have been tried for the removal of CO₂, among them sorption method was found to be more simple and economical. Majority of research work related to CO₂ sequestration was carried out using Thermo Gravimetric Analysis (TGA). In the present study an attempt was made to study high temperature CO₂ sorption using self-fabricated packed bed column in pilot scale. In this work the absorption column was designed to utilize the flue gas temperature for effective sorption of carbon dioxide using Calcium hydroxide [Ca(OH)₂] as a sorbent. The Ca(OH)₂ was made into cylindrical extrudates. The gas mixture containing nitrogen and carbon dioxide was heated and subjected to CO₂ sorption using Ca(OH)₂. The sorption process for various temperatures was studied at a constant flow rate and fixed bed height. Concentration of CO₂ was measured using a flue gas analyzer (NDIR sensors). The temperature was found to be major factor affecting sorption process. The optimum temperature was found to be 300 °C. Increase in the temperature above 300 °C, resulted in sintering and weight loss of the sorbent. The conversion of Ca(OH)₂ to CaCO₃ is confirmed by FT-IR, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis(EDAX) and XRD.

This paper discusses the impact of the structure and properties of three different polymer binders: polyvinylidene fluoride, sodium carboxymethyl cellulose and polyvinyl alcohol, on the electrochemical properties of spherical graphite anodes for Li-ion batteries. Electrochemical tests indicate that the nature of polyvinylidene fluoride contributes in decreasing the cycle life of graphite electrodes in contrast to effective water-based binders. This study demonstrates the possibility of manufacturing graphite-based electrode for Li-ion batteries that cycle longer and use water in the processing, instead of hazardous organic solvents like N-methylpyrrolidone, thereby improving performance, reducing cost and protecting the environment.

The adsorption of C₁₀, C₁₁ and C₁₈ fatty acids from aqueous solution is a phenomenon of major importance in flotation, geochemistry and oceanography. There is an approach that allows identifying the origin of the formation of aggregates of condensed molecules and the filling mechanism of the adsorbed layer. The different homogeneous domains of the surface are filled by decreasing energetic order. The size of different homogeneous domains controls the size of the lamellar aggregates to one layer and two layers for high concentration. Fatty acid adsorption was investigated at the calcite surface by infrared spectroscopy, atomic force microscopy and X-ray diffraction studies. The adsorption process was studied for different fatty acids in acid medium created by phosphoric acid at pH = 4.8-5.0.

Podophyllotoxin has captured the attention of chemists all over the world for its biological activity. It was isolated from many plants of Podophyllum species such as Podophyllum emodi, Podophyllum peltatum and others. It mainly exhibits anticancer, antimitotic, antimalarial, anti-aids and other activities. Its use is restricted due to its toxicity and unfavourable solubility. It was aimed to synthesize some new heterocyclic analogues of podophyllotoxin by changing the substituents by changing lactone ring with pyrazoline ring and substituents in ring C with hydrogen and methoxy group. Chalcones were prepared by Claisen-Schmidt reaction of 1,3-methylene dioxyacetophenone with benzaldehyde and p-anisaldehyde. The reaction of chalcone with trimethylsulphoxonium iodide in presence of sodium hydride gave cyclopropyl ketone. Intramolecular cyclization reaction of cyclopropyl ketone gave tetralone intermediates of podophyllotoxin. They are obtained in good yields. The structure of all the products was confirmed by spectral data.

Reaction of 2-amino-5-nitrophenylmercuric chloride with 3-nitro benzaldehyde gave 2-(3-nitrobenzylideneamino)-5-nitrophenylmercuric chloride (1). Reaction of the mercurated Schiff bases 1 with tellurium tetrabromide in 2:1 mole ratio gave the tellurated Schiff bases, bis[2-(3-nitrobenzylidineamino)-5-nitrophenyl] tellurium dibromide (2). Reduction of compound 2 by hydrazine hydrate gave the corresponding telluride, bis[2-(3-nitro benzylideneamino)-5-nitrophenyl]telluride (3). Complexation reactions of equilibrium mole ratios compound 3 with MnCl₂.4H₂O, CoCl₂.6H₂O and NiCl₂.6H₂O gave the corresponding complexes, i.e compounds 4-6, respectively. All the prepared compounds were characterized by elemental analysis, conductivity measurements and ¹H and ¹³C NMR, FT-IR and UV-visible spectroscopic data. These data suggested that the compound 3 coordinate with metal ions as tridentate ligand. The molar conductivity study indicated compounds 1-3 are neutral and behave as non-electrolytes in DMSO solvent at room temperature while compounds 4-6 behave as 1:1 electrolytes in the same conditions. The molar ratio method was used to determine metal-ligand ratio, which was found as 1:1, metal: ligand. The thermal analysis of compounds 2 and 3 were also investigated and discussed.

A new sensitive, simple, rapid, accurate and precise spectrofluorimetric method for determination of diflunisal and its impurity is developed. Determination of diflunisal is based on first derivative spectrofluorimetric method, while its impurity can be determined by zero order spectrofluorimetric method. Diflunisal was measured at zero-crossing wavelength 394nm (zero crossing point with its impurity) which was selected for quantification of diflunisal. The impurity was measured directly at 334 nm, using 0.05 M phosphate buffer (pH = 9) as solvent. The analytical signal resulting from first derivative and zero order spectra were measured for diflunisal and its impurity, respectively. Linearity was over the range of 0.1-0.9 μg/mL for both with detection limit of 0.02 and 0.03 μg/mL and quantitation limit of 0.07 and 0.09 μg/mL for diflunisal and its impurity, respectively. The proposed method was validated as per ICH guidelines.The accuracy was checked by applying the proposed method for the determination of the drug and its impurity, the mean percentage recoveries were found to be 99.61±0.911 and 100.41±1.373 for diflunisal and its impurity, respectively. RSD values for repeatability testing were 0.268 and 0.569 and for intermediate precision were 0.224 and 0.259 for diflunisal and its impurity, respectively. The proposed method was effectively applied to analysis of studied drug in its tablet formulation. The results obtained by it were statistically compared with the reported method revealing high accuracy and good precision.

A series of new cholesterol derivatives have been prepared via Mitsunobu reaction. The reaction was monitored by thin-layer chromatography (TLC) technique. All new compounds were characterized by melting points, elemental analysis, FT-IR, ¹H, ¹³C and 2D-NMR spectroscopy. The antibacterial and antifungal activity of these derivatives was also determined. The phase transitions of the prepared derivatives were measured with the aid of differential scanning calorimetry. The textures of the mesophases have been determined with a hot stage equipped polarizing microscope, also the electrical conductivity of the solutions of these liquid crystals measured by electrical conductivity meter. The analysis showed that these prepared derivatives were liquid crystals.

Selective and sensitive ultra-performance liquid chromatography-tandem mass spectrometric technique (UPLC-MS/MS) was investigated for simultaneous determination of acemetacin (ACM) in presence of its metabolite (indomethacin) and degradation products in 3 min run time. The column employed was a Hypersil gold 50 mm × 2.1 mm (1.9 μm) with an isocratic mobile phase consisted of 0.1% formic acid aqueous solution and acetonitrile (10:90, v:v)  with flow rate 250 µL/min. Detection of the cited drug was carried out using multiple reaction monitoring (MRM) mode on a triple quadrupole mass spectrometer coupled with electrospray ionization (ESI) m/z 416.44 → 139.24 for ACM and m/z 256.31 → 167.00 for diphenhydramine internal standard. Various parameters were studied; mobile phase composition, flow rate, rate of fragmentation, rate of collision and mode of ionization. Good linear relationship was obtained in concentration range 8.0-500.0 ng/mL (r = 0.9994). The method was validated (linearity, range, precision, accuracy, limit of quantification and limit of detection) according to ICH guidelines and there is no significance difference between the proposed method and the reference HPLC method regarding accuracy and precision. The simplicity and sensitivity of this method allows its use as stability indicating method.

The use of renewable chemicals has become one of the most rapidly developing trends in chemical synthesis. Numerous naturally occurring compounds become green alternatives for traditional oleochemicals due to the fact that they exhibit a wide range of attractive properties. Substances such as pelargonic (nonanoic) acid, which are obtained as secondary metabolites from plants or microorganisms, play a major role in their defense systems by protecting them from diseases, herbivores or predators. Therefore, due to their unique biological properties, the natural chemicals are potential components of ionic liquids (ILs). In this study, the synthesis and properties of ammonium ILs with nonanoate anion are presented. The reactions were conducted in a short time under ambient temperature and pressure. The products were obtained with high yields. The synthesized ILs were characterized by good surface active properties. Didecyldimethylammonium nonanoate reduced the surface tension of water to 21.86 mN/m. The feeding deterrence activity of the obtained nonanoates was also examined and the studied ILs exhibited high feeding deterrence activity, comparable to natural occurring antifeedants, azadirachtin. Additionally, the synthesized ILs were also active towards rods, cocci and fungi. The obtained results allowed to link surface properties with biological activity of synthesized ILs.

New compounds of phosphorus fluorinated 2,4,6-trimethylphenylazo pyridines (4a-c) have been synthesized in high yields via adding n-butyl lithium in hexane to a stirred solution of methyldiphenylphosphine oxide in dry THF at 0 °C, then cooled to around -78 °C, treated with azo-pyridines(2a-c) and then allowed to warm at room temperature over 2 h. The isomers of (E)-((5-chloro-3,6-difuoro-4-(mesityldiazenyl)pyridin-2-yl)methyl)diphenyl phosphine oxide (4b) and (E)-((3,6-difuoro-4-(mesityldiazenyl)5-methoxypyridin-2-yl)methyl)diphenyl phosphine oxide (4c) can be separated on analytical HPLC: Chiralcel OD-H column, hexane:2-PrOH, (9:1, v:v) mobile phase, flow-rate, 1.0 mL/min, 25 °C, λ = 254 nm and polarimetric detection, 20 µL injection volume. The resolution of this isomers were 2.12, 1.84, respectively.

Reaction of 4-phenyldiazenyl /or 4-(p-tolyldiazenyl)-1-naphthol (1) with various substituted α-cyanocinnamonitriles (2a-h) and ethyl α-cyanocinnamates (2i-p) afforded 2-amino-4-(aryl)-6-(phenyldiazenyl /or p-tolyldiazenyl)-4H-naphtho[1,2-b]pyrano-3-carbonitrile (3a-h) and ethyl 2-amino-4-(aryl)-6-(phenyldiazenyl /or p-tolyldiazenyl)-4H-naphtho[1,2-b]pyrano-3-carboxylate (3i-p). Reaction of compound 3a with Ac₂O or PhCOCl and formic acid afforded N-acetylamino or N,N-dibenzoylamino and naphthopyranopyrimidine derivatives (4-8), respectively. The structures of these compounds were established on the basis of IR, UV, ¹H NMR, ¹³C NMR, and MS data.

The aim of this work was to develop and validate a simple, sensitive and rapid method for the quantitation of levetiracetam (LEV) in plasma using LC-Tandem mass spectrometry. Plasma samples were prepared by simple protein precipitation using acetonitrile; atenolol was used as internal standard (IS). Chromatographic separation was done on Luna 5 µm C18(2) (Phenomenex) 50 × 2.0 mm using gradient flow using solvent A (0.1% formic acid) and solvent B (0.1% formic acid in acetonitrile: water, 95:5, v:v). The positive-ion mass spectrometric detection method utilized electrospray ionization and the multiple reaction monitoring (MRM) mode. The MRM ion transitions were170.9 → 140.8 and 267.3 → 145.1 for levetiracetam and atenolol, respectively. The retention time of levetiracetam and atenolol is 3.24 and 2.96 min, respectively. The total run time was 5 min. The assay was validated over a concentration range from 1 to 100 µg/mL. The method was robust (minimal matrix effect), sensitive (LOQ, 1 µg/mL) metabolites and reproducible (The precision and accuracy for both intra- and inter-day were acceptable <15%). The method can be done on traditional LC-MS equipment. The method was effectively applied to single case study receiving toxic dose of LEV.

Treatment and disposal of emission gases used for fertilizer production are among the most pressing issues in the modern fertilizer industries. Associations such as the European Manufacturer Association are developing new techniques, i.e., best available techniques, to resolve such problems. Best available techniques have been developed by the European Manufacturer Association to standardize the solutions to common problems encountered in the fertilizer industry, such as optimization of pH, pressure, temperature, nitrogen content, and fertilizer particle size. The best available techniques aim at minimizing greenhouse gas emissions in the fertilizer industry as well as wastewater treatment and waste management. The high operation and investment costs in the fertilizer industry have prompted manufacturers to consider the application of the best available techniques.

Direct and selective carbon-hydrogen bond functionalization has attracted enormous attention because it provides more efficient strategies for preparing valuable functional molecules from easily available substrates. Significant and exciting developments in functionalization of un-activation Csp³-H bonds have continuously been made over the past few decades. This review mainly summarizes recent advances on direct Csp³-H bond functionalization for the formation of C-C and C-heteroatom bond under transition-metal-catalysed and metal-free conditions.