Journal of Applied Chemical Research
Year:2016 | Volume:10 | Issue:3|Papers Count:12

A simple, inexpensive and sensitive three-phase hollow fiber liquid-phase microextraction (HFLPME) coupled with high performance liquid chromatography (HPLC) with UV detection was successfully developed for determination of trace level of an anti-Histamine drug, fexofenadine, in human plasma and urine. The analyte was extracted into n-octanol that was immobilized in the wall of a porous hollow fiber from 15 mL of aqueous sample, with pH 4 (donor phase), and was back extracted into the acceptor phase with pH 9 located in the lumen of the hollow fiber. The extraction occurred due to a pH gradient between the sides of the hollow fiber. Several parameters affecting the extraction process such as type of extraction solvent, pH, salt concentration, extraction time, and stirring speed were optimized. Under the optimized conditions enrichment factor of 65, linear dynamic range (LDR) of 1.8-200 ng/mL and limit of detection (LOD) 0.6 ng/mL were obtained. The percent relative intraday and interday standard deviations (RSD%) based on 3 replicate determinations were 7.1% and 7.6% respectively.

A novel, convenient and efficient multi-component reaction for synthesis of phosphonate derivatives from activated acetylenic compounds with 2-hydroxyacetophenone in the presence of phosphites in water lead to the formation of phosphonates in good yields.

Calcium carbonate is a cheap and readily available filler used in rubber industry. This material is not compatible with rubber matrix, so many researchers have tried to modify its surface with various materials in order to increase its hydrophobicity and improve compatibility with the rubber matrix. In this effort, surface modification of calcium carbonate was carried out by 1.5%, 3% and 4% stearic acid to achieve the technical knowledge of preparation method. The surface adjustments were investigated by Fourier transform infrared spectroscopy (FTIR), thermal analysis (TA), and scanning electron microscopy (SEM) and were compared with imported surface modified calcium carbonate (ISMCC) used in the rubber industry. Results showed surface modifications have been accomplished successfully. Furthermore, efficiencies of the prepared surface modified calcium carbonates (SMCCs) were investigated as fillers in the NR/SBR-based compounds. Cure characteristics and physico-mechanical properties of the compounds were considered and compared with reference compound that contained ISMCC. Using calcium carbonate modified by 3% stearic acid as a filler (SMCC (2)) not only preserved compound properties but also improved tensile properties, shortened the cure time and improved aging resistance in comparison with ISMCC.

A highly efficient and simple protocol for the synthesis of 2-amidoalkylphenols has been described. The one-pot multi-component condensation of phenols with aromatic aldehydes and amides in the presence of catalytic amount of SO3H-functionalized phthalimide (SFP) under solvent-free conditions afford the title compounds in high yields and relatively short reaction times. It is noteworthy that the reaction between phenols, arylaldehydes and amides has been scarcely studied in the literature (in spite of the condensation of 2-naphthol with arylaldehydes and amides, which has been extensively reported).

Polyvinyl alcohol/ glycerin- magnetic iron oxide nanoparticles (PVAGLPs) have been synthesized successfully by hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectra (FTIR). The adsorbed activities of the polyvinyl alcohol/ glycerin- magnetic iron oxide nano particles (PVAGLPs) were carried out varying parameters for adsorption Cr (III) and Hg (II) ions. Adsorption experiments were carried out varying parameters such as initial metal ion concentration (10-100 ml/g), pH (1-9), contact time (10-120 min) and weight of adsorbents (0.1-0.6 g). The increase in metal uptake with increase in dose of adsorbent from 0.1 – 0.6g was due to the increase in surface area and number of active sites for the adsorption. Shows that the adsorbent of metal ions increased from 65 to 92% and 54 to 82% for Hg (II) and Cr (III) respectively. Optimum conditions for the removal of Cr (III) and Hg (II) with PVAGLPs are: 0.4 g of adsorbent, concentration 50 ppm, at 25oC and at pH 5.0 for Cr (III) and 4.0 for Hg (II).

Polyaniline/Fe3O4 magnetic nanoparticles were synthesized and employed as a sorbent for the magnetic solid phase extraction (MSPE) of seven triazine herbicides from environmental water samples. The properties of the prepared magnetic sorbent were characterized using field emission-scanning electron microscopy (FE-SEM), fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA) methods. Effect of the different parameters influencing the MSPE efficiency, such as sample pH, sorbent amount, and extraction time were investigated and optimized. The amount of enrichment factors for triazines using proposed method were found in the range of 26-49. Calibration curves of triazines showed linearity in the range of 1-1000, 2-1000 and 5-1000 mg/L for analytes. In addition, the detection limits for the analytes were in the range of 0.2-0.9 mg/L. The values of relative standard deviation (RSD%) for n=5 at the concentration level of 10 mg/L were obtained lower than 3.1% for all analytes. Capability of polyaniline/Fe3O4 magnetic nanoparticles in extraction of triazines was compared with naked Fe3O4 and polyaniline. The proposed method was also successfully applied to the extraction of triazine herbicides from environmental samples and satisfactory relative recoveries were obtained.

Modafinil (Diphenyl methyl Sulfinyl acetamid) is used clinically in the treatment of narcolepsy and sleeping disorders. The synthesis of R-modafinil, have started with the reaction of benzhydrol and thioglycolic acid in trifluoroacetic acid to afford benzhydryl sulfanyl acetic acid. The reaction of acid with thionyl chloride in benzene followed by treatment with ammonium hydroxide gave acetamide. The process occurs at room temperature in toluene as a solvent and in the presence of a bidendate diethyltartarate–titanium isopropoxide complex as chiral catalyst. The reaction using this catalyst exhibits very good yield and appropriate enantioselectivity. The obtained products were characterized with FT-IR, 1H NMR, 13C NMR, and mass spectral. The ee of the obtained sulphoxide has been determined by high performance liquid chromatography (HPLC).

N- (2H- [1, 2, 4] thiadiazolo [2, 3-a] pyridine-2-ylidene) benzamide was used as a selective sensing material in the PVC membrane to construction of a new chromium ion selective electrode. This liquid membrane electrode worked well with a Nernstian response of 19.7±0.4 mV decade-1 of Cr (III) in a wide dynamic concentration range of 8.0´10-6-1.0´10-1 M. The electrode had relatively short response time (about 5 s), and it was found to produce stable responses for more than 60 days. The effects of some factors such as internal solution, pH, life time and selectivity were investigated. The electrode has a useful working pH range of 3.5–8. Selectivity coefficients determined with match potential method. The selectivity coefficients indicate high selectivity towards Cr (III) ions. The practical utility of the Cr (III) ion sensor has been demonstrated by using it as an indicator electrode in potentiometric titration of Cr (III) with EDTA and for direct determination of Cr (III) in tea and Cocoa powder samples.

An efficient approach to the synthesis of 1, 2, 3-trisubstituted indolizines is described via one-pot reactions of pyridine and dialkyl acetylendicarboxylate in the presence of ethyl 2-chloroacetoacetate in MeOH at room temperature. The corresponding 1, 2, 3-trisubstituted indolizines may be useful building blocks for the construction of complex indolizine derivatives.

A simple and ecofriendly method was developed for the synthesis of arylmethylene [bis (5, 5- dimethyl-3-hydroxy-2-cyclohexene-1-ones)] from the reaction of 5, 5-dimethylcyclohexane- 1, 3-dione and aromatic aldehydes in an aqueous media without any catalyst via Knoevenagel condensation followed by rapid Michael addition. No cyclization product was down to convert these enolic forms to xanthene derivatives. Diverse aromatic aldehyde including electron-withdrawing (such as nitro group) groups or electron-donating groups (methoxy group) was used to give the corresponding dienolic forms successfully. This method provided several advantages such as simple work-up procedure, high yield, short reaction time and environmentally friendly nature.

Some new coordination compounds of tin (IV) having general formula [SnBu2 (L)2] (where L=carbohydrazone ligand) have been synthesized by the reaction of dibutyltin oxide with carbohydrazone ligands with the ratio of 1: 2 (metal- ligand) using dry benzene as a reaction medium. The newly synthesized complexes were characterized by elemental analysis, molecular weight determinations, conductivity measurement and spectral analysis viz., IR, UV-Vis and NMR (1H, 13C and 119Sn). A distorted octahedral geometry of these complexes has been assigned on the basis of spectral studies. The biological activities of carbohydrazones and their Sn (IV) complexes have been screened in vitro against some bacterial and fungal strain to assess their growth inhibitory potency. Most of the metal complexes exhibit more antibacterial and antifungal activities than the free carbohydrazone ligands against these organisms.

In this study simple catalytic test experiment was performed in a flask of rotary evaporator for dechlorination of nitrochlorobenzene (NCB) over two samples of Ni/LaAl2O3 nanocatalysts (C1 and C2). In the reaction, Ni acts as a catalyst to collect hydrogen gas in aqueous solution and dissociate it to produce active hydrogen atoms for replacing the chlorine. The catalysts were characterized by scanning electron microscope (SEM), X-ray fluorescence (XRF), X-ray diffraction (XRD), BET specific surface area, and particle size analysis (PSA) techniques. The Ni/La-Al2O3 catalyst prepared by aluminium nitrate exhibits greater specific surface area and higher dechlorination efficiency compared to sample prepared through aluminium triisopropoxide precursor.