Applied Chemistry

The reignited research on biodiesel production has witnessed, in recent decades, so much momentum to lead a great revolution in world energy in the near future. This great resurgence is stimulated in one part by the anxiety of the uncertainty of the supply life span of conventional fuels and in the other by the numerous advantages that biodiesel offer over petroleum diesel fuel. Biodiesel, amongst other benefits, is renewable, biodegradable, environmentally benign, energy efficient, and by far a major role-player in the league of biofuels that will sustain the energy future. Starting from history to present, this work presents a comprehensive review of major advance in biodiesel production. The five basic ways of making biodiesel: direct use and dilution, microemulsions, thermal cracking and transesterification are reviewed with emphasis on heterogeneous catalyst transesterification. Progresses in research into other methods such as enzyme catalysed, non-catalytic supercritical and ultrasound aided transesterification, biox co-solvent and in situ processes as well as production from microalgae are detailed. The factors affecting the yield of the different processes are identified and recommendations are presented for optimum production yield. Evaluation of the economic viability of biodiesel production shows the major challenges as the cost of production and limited availability of fat and oil resources. Microalgae prove to be the economical choice for biodiesel production, because of the availability, high productivity and low cost. Therefore, research should be geared towards the improvement and optimization of biodiesel production from algae.

Treatment and disposal of oily wastewater, presently is one of the serious environmental problems contributors. Numerous methods have been used to remove residual oil from wastewater, such as adsorption, flocculation, electrocoagulation and flotation. The focus of this research was to prepare and investigate the using of chitosan as an oil adsorbent and coagulant of the excessive residue oil droplets from an oily wastewater. In this respect, shrimp waste (shell) was treated with 9% (w/w) NaOH at 65oC for 90 min to obtain a purified crab chitin, and then 1g of purified crab chitin was treated with (w/w) 50% sodium hydroxide solution at 136oC for 1h to obtain pure chitosan. The prepared chitin and chitosan were characterized by the FT-IR spectrometry, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The FT-IR spectrum shows three characteristic absorption bands of chitosan one of them was very strong and appeared at about 3306 cm-1 this for stretching vibration bands of (N-H and O-H), the second strong one appeared at about 1593.54 cm-1 that assigned for (-CONH-) and the third band at 1054.90 cm-1 for (C-O-C). The XRD patterns of chitosan show two characteristics crystalline peaks at 2? of 9.24° and 19.2° indicates the formation of chitosan from chitin. The surface morphology of chitosan before and after oil adsorption was examined using SEM. Then, the percentage of oil droplets removal was evaluated by HPLC.

The adsorption and inhibition of Aluminium corrosion in 1.0 M HCl using different concentrations of extracts of Baissea axillaris was investigated at 303 and 323K using weight loss technique. Weight loss and corrosion rate increased with increase in temperature both for the free acid and inhibited solutions, with marked reluctance to increase in both observable in for the presence of the extracts, varying with the extract concentration. Inhibition efficiency increased with increase in the concentration of the extract. The maximum inhibition efficiency of 86.3% was obtained for 10 µg/L extract but decreased to 68.4 % on increasing the temperature from 303 K to 323 K. The adsorption was best described by the Temkin and Langmuir adsorption isotherm from where negative Gibbs free energy change was obtained indicating spontaneous adsorption while negative heat of adsorption was obtained indicating exothermicity. Activation Energy was deduced from the Arrhenius equation while thermodynamic approach yielded the heat of adsorption.

The photocatalytic activity was studied under UV light using AC-Cd/TiO2 prepared via precipitation method and characterized by powder X-ray diffraction (XRD) , high resolution scanning electron micrographs (HR-SEM) with energy dispersive X-ray analysis (EDX), photoluminescence (PL) and Fourier transform Raman analysis (FT-RAMAN). The enhanced photo catalytic activity of the AC-Cd/TiO2 is demonstrated through photodegradation of methylene blue under UV light radiation at 365 nm. The mechanism of photocatalytic effect of AC-Cd/TiO2 Nano composite material has been discussed Further its antibacterial activity against two gram positive and two gram negative bacterial strain is studied.

The measurement of ultrasonic velocity in pure liquids and mixtures is an important tool to study the physico-chemical properties and also explain the nature of molecular interactions. The study of thermodynamic parameters to explain molecular interaction of drugs in aqueous or non-aqueous medium provides useful information in medicinal and pharmaceutical chemistry. In present work molecular interaction of aqueous solution of Gabpentin (2-[1-(amino methyl) cyclohexyl] acetic acid) at various concentrations and different temperatures such as 303, 308, 313, 318, 323K was studied by measuring ultrasonic velocity, density and viscosity of the solution. The ultrasonic parameters such as adiabatic compressibility, free volume, free length, acoustic impedance, absorption coefficient, viscous relaxation time, available volume, and Lenard Jones Potential were calculated. These parameters explained formation of hydrogen bond and molecular interaction existing in the solution.

Ab initio and Density functional theory with three basis sets have been used to study seventeen isomers comprising of six thioaldehydes and eleven thioketones, relative stabilities of the isomers and electronic properties of the molecules are reported. The results revealed that there is an increase in C=S bond length as the number of carbon atoms increases, although C=S bond lengths for thioaldehydes are shorter than that of the corresponding thioketones analogues. Generally, thioketone isomers are more thermodynamically stable than that of the corresponding thioaldehydes. The rearrangement of thioaldehydes to thioketones would be feasible and exothermic since both ?G? and ?H? have negative values. 13C NMR of thiocarbonyl carbon atoms and UV-visible absorption (?max) showed similar trend when plotted against C=S bond length, thus the electronic properties and chemical reactivities of the molecules would be predominantly governed by C=S group.

A rapid, sensitive reversed phase stability-indicating high-performance liquid chromatographic (HPLC) assay method was developed and validated for quantitative determination of carmustine in bulk drugs and the degradation products generated from forced degradation. A gradient, reversed phase HPLC method was developed to separate the drug from the degradation products, using an YMC ODS-A C18 (250mm x 4.6) mm,5u column and the Mobile phase-A 0.01 M Potassium dihydrogen phosphate in water, adjust PH 3.2 with orthophosphuric acid and mobile phase-B methanol was used as mobile phase. The detection was carried out at wavelength 230 nm and 205 nm. The chromatographic resolution between its degraded products was found to be greater than two. The carmustine was subjected to stress conditions of acid, base, oxidation (30 % H2O2), thermal degradation and photolytic degradation. The degradation was observed for carmustine in alkali, acid and in thermal hydrolysis. The mass balance was close to 100 in all the stress conditions. The degraded products were well resolved from main peak. The developed method was validated with respect to linearity, accuracy, recovery, precision, system suitability, selectivity, robustness and forced degradation studies prove the stability indicating ability of the method.

An isocratic reversed phase stability-indicating high-performance liquid chromatographic (HPLC) assay method was developed and validated for quantitative determination of Nicardipine hydrochloride in bulk drugs and the degradation products generated from forced decomposition. An isocratic, reversed phase HPLC method was developed to separate the drug from the degradation products, using an Waters Symmetry shield C18 (250 x 4.6)mm,5u column and the mobile phase containing the of mixture of triethylamine-phosphoric acid buffer (pH-3.5 by orthophosphoric acid, acetonitrile (35:65,v/v). The detection was carried out at wavelength 353 nm. The Nicardipine hydrochloride was subjected to stress conditions of hydrolysis (acid, base), oxidation (50 % H2O2).The degradation was observed for buclizine hydrochloride in base and negligible degradation observed 50 % H2O2. The mass balance was close to 100 in all the stress conditions. The degraded products were well resolved from main peak. The developed method was validated with respect to linearity, accuracy (recovery), precision, system suitability, selectivity, robustness and forced degradation studies prove the stability indicating ability of the method.

Statistics show that the consumption of plastics has been increasing every year. To reduce environment waste plastic they must be recycled. Among the various types of recycling, pyrolysis in general, offers an environmentally attractive method to decompose wide spectrum of wastes, including waste plastics. Pyrolysis of plastic waste results in char, pyro oil and pyro gases. The derived oils may be used directly as fuel or added to petroleum refinery feed stock. The gases are also useful as fuel and solid char may be used as either smokeless and fuel or activated carbon or can be gasified for production of fuel gases. In this paper a detailed literature of pyrolysis of waste plastic materials is reviewed and the effect of process parameters on the yield of pyrolysis products was discussed.

In the title compound, C22H19ClN4, the pyrrole and pyrimidine rings form a dihetrocyclic fused pyrrolo-pyrimidine ring system which is almost co-planar; dihedral angle between two ring planes is 6.2º, to which five membered pyrrolidine ring is substituted, which is puckered to attain half chair conformation. Two other rings chloro-phenyl and phenyl are substituted at the 7 and 9 positions respectively in the fused ring system. Chloro-phenyl ring also shares the plane of fused ring system. (Dihedral angle between two ring system is 12.4º.) Crystal packing is stabilized due to ?-? interaction observed between pyrrole and chloro-phenyl ring of its symmetry related molecules (centroid-centroid distance: 3.8641 Å). Intramolecular C-H…N hydrogen bond is also observed in the molecular structure.