Applied Chemistry

Ultrasonic velocity, density and viscosity for binary liquid mixture of fatty acid ester Ethyl Oleate with toluene have been measured at 2 MHz ultrasonic frequency within the temperature range of 303.15K to 318.15k. Thermo-acoustic parameters like adiabatic compressibility, acoustic impedance and intermolecular free length are calculated. The results are interpreted for interaction studies among the molecules of the mixtures.

The crystal structure of the title organic-inorganic hybrid material [C₃H₆N₃S₂]H₂PO₄, has been determined by single crystal X-ray diffraction. The compound crystallizes in the noncentrosymmetric orthorhombic space group Pna2₁ with the lattice parameters a = 7.662 (1), b = 26.553 (3), c =  4.4258 (6) Å, V = 900.4 (2) Å3, and Z = 4. The framework is built upon layers parallel to (0 1 0) made up from H₂PO₄^- entities associated by O---H...O strong hydrogen bonds. The organic cations are located between the layers and connect them via N-H…O and C-H…O hydrogen bonding network. The exocyclic C-N bond length reveals the presence of the imine and enamine tautomers in the starting reagent. Results from solid state ¹H, ³¹P, ¹³C and ¹⁵N spectroscopy are in good agreement with the X-ray structure. Density functional theory calculations allowed for the assignment of the carbon and nitrogen peaks to the independent crystallographic sites.

The physicochemical parameters and some contaminants of crude oil samples from the Jubilee oil field at Cape Three Points, western region and Saltpond oil field in Central region of Ghana were analyzed to classify and assess the quality of the crude oils. The physicochemical parameters determined were density, specific gravity, API, pour point, total sulphur content, salt in crude, total acid number, viscosity, reid vapour pressure and ash weight whereas the contaminants measured were water and sediments. Results from the physicochemical parameters for both samples showed a perfect Pearson’s correlation (r ?1). Low water and sediments levels (<1%) were recorded for both crude oils. This is an indication of low or minimal microbial growth and reduced ability of both crude oils to serve as a collector of water soluble metals and salts. This enhances the quality of the crude oils making them less fouling and corrosion resistant at high temperatures. High API values (API>30), coupled with low specific gravity, viscosity and pour point for both crude oils make them light crude oils. The sulphur concentration for both samples were low and within globally accepted range of 0.1-0.5 wt. % for sweet crude oil.

Cold extraction method was used extract the crude solvent extracts of leaf of Chrysophyllum albidum. The structural elucidation by spectroscopic methods (1H and 13C NMR) of a fraction of ethyl acetae extract of C. albidum yielded a new compound characterized as decyl heptadecanoate, C27H54O2. A similar compound Decyl-8-hydroxyl heptadecanoate has also been isolated from Ziziphus mauritiana leaves and has been synthesized via utilization of microwave energy using available starting compounds. Quantum chemical calculations have been carried out on the isolated compounds. Optimized geometry, IR frequencies, bond distances, bond angles and other parameters have been computationally determined for the isolated compound from the quantum chemical calculations using the GAUSSIAN 09 suite of programs. The experimentally measured and the computationally obtained IR frequencies are in good agreement.

The crystal structure of the title organic-inorganic hybrid material C7H7N2•NO3 has been determined by single crystal X-ray diffraction. The compound crystallizes in the noncentrosymmetric orthorhombic space group Pca21 with the lattice parameters a = 15.824 (1), b = 6.5461 (4), c = 16.215 (1) (6) Å, V = 1679.64 (18) Å3, and Z = 8. The framework is built upon layers parallel to (0 0 1) made up from the nitrate anions and the ammonium groups associated by N---H...O and N---H...N hydrogen bonds. The organic entities are interconnected via weak C-H…N hydrogen bonds involving the nitrogen atoms of the nitrile groups, leading to an infinite one-dimensional chains running along the a-axis. These chains are located alternatively on either side of the ionic layers. Results from solid state 1H, 13C and 15N spectroscopy are in good agreement with the X-ray structure. Density functional theory calculations allowed for the assignment of some carbon and nitrogen peaks to the independent crystallographic sites. The IR spectrum is dominated by the antisymmetric stretching mode of NO3-, which splits into two components indicating that the symmetry of the nitrate anion is lowered by interaction with the ammonium group.

An expedious one pot, synthesis of bis (indolyl) methane was achieved in quantative yield, utilizing indole and substituted aromatic aldehyde using 5-SulphoSalicyclic Acid as a catalyst at room temperature within a short period of time.

this present study, adsorption capacity of groundnut shell activated carbon coated with Fe3O4 as a low cost adsorbent for removal of cationic dye, Rhodamine B (RDB) from aqueous solution was explored. The surface morphology and functional groups present were investigated by scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy. The effect of various parameters such as contact time, pH, adsorbent dosage and concentration of adsorbate were studied at ambient temperature. Equilibrium data were analysed using Langmuir, Freundlich and Temkin isotherm models. Kinetic data were studied using Pseudo-first and Pseudo-second order kinetic models and the mechanism of adsorption was described by intraparticle diffusion model.

Presently a stability indicating RP-HPLC method was developed for the estimation of Sitagliptin Phosphate monohydrate in pharmaceutical dosage forms . A 0.1 M KH2 PO4 solution was used as the buffer solution .Buffer and acetonitrile were mixed in the ratio 50:50 ,the resulting solution was sonicated to dissolve and degassed by vacuum filtration through 0.4 µ membrane filter and the resulting solution was used as mobile phase and diluent. Chromatograms were recorded using Inertsil ODS, C18 ,150 mm x 4.6 mm , 5 µ column at a temperature of 300 C with isocratic elusion .The detection wave length was 268 nm at a flow rate of 1.0 mL per minute .Each injection volume was 20 µL. The retention times for Sitagliptin Phosphate standard and sample were 3.613 and 3.618 min respectively. Linear calibration curve was obtained over the concentration range of 2.5 -15.0 µg /mL with a slope, intercept, Standard deviation and correlation coefficient of respectively 35792,10262,669649.4 and 0.999 respecively. The present method was validated as per ICH guidelines for Specificity, Linearity, Accuracy ,Precision, Ruggedness and found suitable for the determination of Sitagliptin Phosphate .The stability indicating studies under different stress conditions revealed that the drug was stable and the % of degradation of the drug was in the range 4.75 -11.57 % .The limit of detection was 61.74 µg-mL and limit of quantification was187.09 µg – mL . The present method was rapid and sensitive for the determination of Sitagliptin Phosphate monohydrate.

A carbon based (Graphene) working electrode containing enzyme alkaline phosphatase, cellulose acetate and Poly Vinyl Pyrolidone (PVP), Ferrocene, Horseradish peroxidise and aq. KOH was specially designed and fabricated. It is then combined with Ag/AgCl reference and a platinum electrode to form a three electrode based amperometric biosensor for the electrochemical detection of Enterobacter aerogenes as biological warfare agent (BWA) in the presence and absence of Fe3O4 nanoparticles. Fe3O4 nanoparticles were synthesized by sol-gel technique and were characterized by UV-visible, FTIR, TEM and XRD techniques. Change in current response and OCP values helps in the detection of BWA in presence and absence of Fe3O4 nanoparticles. Effects of temperature, stirring and Fe3O4 nanoparticles on the BWA have also been investigated.

Several substituted N-Phenyl maleimide were prepared and their mass spectra in EI mode were recorded. The effects of substituents on the mass spectral fragmentation of compounds under investigation are interpreted by correlating log Z/Z0 with simple and extended Hammett equations. The log Z/Z0 values in all the cases were subjected to multiple linear regression analysis using two sets of biparametric equations (Taft and Swain equations). The results of the multiple linear regression analysis are found to be good in the cases.