Applied Chemistry

Alkylation reactions of phenol with dimerization products of devinylated C4-fraction obtained by the pyrolysis of low-octane gasoil were studied in the presence of KU-23 catalyst. Alkylation reaction was carried out on the continuous unit. As a result of alkylation reaction, it was studied the influence of temperature, time, initial components mol ratios and catalyst amount on the yield and selectivity. From the results of the researches it’s evident that alkylation of phenol pyrolysis process with dimerization products of C4-fraction in the presence of KU-23 catalyst are carried out under the following conditions: tempe¬rature 120°C, mole ratio of phenol to the fraction - 1:2, reaction time - 5 hours and catalyst amount - 10%. In this case the yield of the target product on phenol was 80.4%, and selectivity on the target pro¬duct was 95.7%.

Solvent extraction of lanthanum(III) and vanadium(V) from their aqueous solutions with chloroform solution of 1-phenyl-3-methyl-4-butanoylpyrazol-5-one (the ligand) was studied. The effects of ligand (extractant) concentrations and the pH of the metal aqueous solutions on the solvent extraction were evaluated in terms of their distribution coefficients (D) and the equilibrium constants (Kex) were determined. The values of the slopes of the plots of log D versus log [HBPy(org)] and that of log D versus pH showed that approximately 3 moles of the HBPy ligand reacted with one mole of La3+ while 2 moles of the same ligand reacted with VO2+ during the extraction process. The average logarithms of the equilibrium constant (Kex) values obtained for the metals at the different HBPy concentrations and buffer 4 are -7.40 (La) and -5.14 (V); while those obtained at the different pH and a constant extractant concentration of 0.02 M are La(BPy)3 = -0.49; and VO2(BPy)2 = -1.39; showing that the ligand is an efficient extractant for V(V) and La(III) ions from their aqueous solutions. The study has shown that separation of the La(III) and V(V) ions in their mixture is possible by the adjustment of the extractant concentrations and the pH of the aqueous solution of such mixture.

A simple method to pre-concentrated Citalopram on C18 modified carbon nanotubes in column has been applied as stationary phase which is used to measure the concentration of Citalopram in water samples by means of solid-phase extraction. To measure 250 mL water samples and 250mg C18 modified carbon nanotubes could be applied. Next step is to measure the Citalopram by injecting them to the gas chromatography with flame ionization. The advantages of applying HPLC with SPE in presence C18 modified carbon nanotubes are high sensitivity, High speed transformation of Citalopram and improving ration standard for river waters with Citalopram in the range of ppb or those with less than 10% of LOD. The quantity of extraction could be affected by sample's pH, amount of solvent, washing liquid type, solvent and flow rates of the sample solutions. The percentage recovery by SPE was 98.00 and the validation parameters proved the precision of the method and its applicability for the determination of citalopram in human plasma.

Simple chemical bonding method to synthesize cyclodextrin–chitosan/nano graphene oxide (CCGO) was reported. The adsorption behaviors of Cu(II) in aqueous solution on CCGO were systematically investigated. The procedure is based on the selective formation of Cu(II) at optimum pH by elution with organic eluents and determination by flame atomic absorption spectrometry. The method is based on complex formation on the surface of the ENVI-18 DISKTM disks modified cyclodextrin–chitosan/nano graphene oxide (CCGO) followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution is efficient and quantitative. The effect of potential interfering ions, pH, CCGO amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to about 1000mL providing a preconcentration factor of 600. The maximum capacity of the disks was found to be 398± 3 µg for Cu2+.The limit of detection of the proposed method is 5ng per 1000mL.The method was applied to the extraction and recovery of copper in different water samples.

Setting a conventional cement plug is nearly unsuccessful when there is any wellbore flow especially for the zechstein formations. As such, the used of sodium silicate remain the common option. The silicate polymerization and gelation has been used in well formation to plug holes and reduce the catastrophic flow which cause a lot of production looses. This is usually encountered during drilling rocks zone producing large amount of water or brine. This could result in large volume of the drilling fluid lost into the formation and consequently reduce the effectiveness of the drilling operations. A well designed silicate/cement material forms an impermeable plug and reduces the adverse of the flow also the in-situ gelation of the process is better understood when the chemistry of the process and the chemical evolution of the brine formation is given due consideration.

A novel and selective method for the fast determination of trace amounts of Co(II) ions in water samples has been developed. The procedure is based on the selective formation of Co(II) ions using mesoporous organo-silicas mesoporous silica at different pH followed by elution with organic eluents and determination by atomic absorption spectrometry The preconcentration factor was 100 (1 ml elution volume) for a 100 ml sample volume. The limit of detection of the proposed method is 1.0 ng ml?1. The maximum sorption capacity of sorbent under optimum conditions has been found to be 5mg of Co per gram of sorbent. The relative standard deviation under optimum conditions was 3.0% (n = 10). Accuracy and application of the method was estimated by using test samples of natural and synthetic water spiked with different amounts of Co(II) ion.

Citrullus lanatus, Cucumeropsis edulis and Lagenaria siceraria are three species of squash widely cultivated and used in food in Benin. The aim of this study is to determinate the physicochemical characteristic and antimicrobial activities of their seeds oil. Oils were obtained by Soxhlet extraction; their quality index were evaluated according to the methods listed in the ‘’AFNOR’’. The oil yield of the seeds of the three cucurbits ranged from 36.23 to 42.28%, the moisture contents of the seeds oils ranged from 0.47 and 0.98%. In terms of quality index, the values are between: 5.04-14.58 mg/g for acid value, 31.70 - 31.86 % for iodine, 1.65 - 8.42 meqO2/Kg-oil for peroxide value, 50.49 - 75.73 mg KOH/g-oil saponification and for ester 40.39 - 70.68%. Their calculated calorific value varies between 44611.05 and 45717.65 Kj /Kg-oil). AAS revealed that these oils had low content of Iron, Manganese and Potassium and do not contain Sodium at all. HPLC showed that the three oils are good sources of fat-soluble vitamins (A, E and K1) with 6.18 mg/100g vitamin E in Citrullus lanatus seeds oil and K1 (0.83 mg / 100g). They were all bacteriostatic and fungistatic on the strains explored but Citrullus lanatus and Cucumeropsis edulis oils had an antibiotic power on Escherichia coli and Staphylococcus aureus.

A novel method for analytical detection of H2O2 based on ruthenium nanoparticles (RuNPs) functionalized chemically reduced graphene (CRGR) nanocomposite is developed. The RuNPs/CRGR nanocomposite was characterized employing different techniques, such as transmitted electron microscope (TEM), cyclic voltammetry (CV) and chronoamperometry (CA). The RuNPs/CRGR nanocomposite sensor exhibits higher catalytic effect to H2O2 by greatly enhancing the reduction peak current and completely eliminating the interference of other species as compared with a bare electrode. A fast amperometric response was observed by the RuNPs/CRGR electrode with a linear range from 10 to 170 µM and lower detection limit of 0.16±0.01 µM as compared to some other reports. The high reproducibility, specificity as well as long time stability obtained with the proposed sensor indicated that the present method is an effective for H2O2 determination.

A reverse phase high performance liquid chromatographic method was developed for the determination of Belinostat in bulk and pharmaceutical dosage form. The separation was affected on a Altima ODS C18 column (150 mm x 4.6 mm,5µ) using a mobile phase mixture of buffer and acetonitrile in a ratio of 40:60 v/v at a flow rate of 1.0mL/min. The detection was made at wave length of 210 nm. Calibration curve was linear over the concentration range of 25 – 150 µg/mL of Belinostat. The proposed method was validated as per International Conference on Harmonization (ICH) guidelines. The method was accurate, precise, specific , rapid and found to be suitable for the quantitative analysis of the drug and dosage forms. Forced degradation studies have been carried out under different conditions.

Heavy metals may be harmful to humans through ingestion of medicinal plants containing metals through atmospheric pollution, pesticides and chemical fertilizers root uptake, ingestion of plants splashed with contaminated soil. Metals of concern are arsenic (As), cadmium (Cd), copper (Cu), Mercury (Hg) and lead (Pb). Removal of the heavy metal ions from contaminated medicinal plants Indigofera tinctoria and Acalypha indica by adsorption technique. It is the best, economically viable and efficient method. It, therefore, becomes necessary to remove these heavy metals from medicinal plants by an appropriate treatment before consuming.